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Home My WebLink AboutAir PM Results April 2025Tuesday, April 1, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. ** Data gap due to instrument malfunction Very Unhealthy Hazardous (355 to 424) (425-504) Location Columbus Square Park Period Ending 04/01/2025 8 AM Matter 8 Level of Concern Good Hangar Fenceline - E Side 04/01/2025 8 AM 10 Good Hangar Fenceline - N Center 04/01/2025 8 AM 7 Good Hangar Fenceline - N Corner 04/01/2025 8 AM 6 Good Hangar Fenceline - NE Corner 04/01/2025 8 AM 8 Good Hangar Fenceline - S Side 04/01/2025 8 AM 10 Good Hangar Fenceline - SW Corner 04/01/2025 8 AM 9 Good Hangar Fenceline - SW Side 04/01/2025 8 AM 5 Good Hangar Fenceline - W Side 04/01/2025 8 AM 4 Good Legacy Road 04/01/2025 8 AM ** ** Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health VIE effects is increased for everyone. 425 to 07.. emergency FM . . . everyone more likely ..- affected. Wednesday, April 2, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. ** Data gap due to instrument malfunction Very Unhealthy Hazardous (355 to 424) (425-504) Location Columbus Square Park Period Ending 04/02/2025 8 AM Matter 13 Level of Concern Good Hangar Fenceline - E Side 04/02/2025 8 AM 14 Good Hangar Fenceline - N Center 04/02/2025 8 AM 10 Good Hangar Fenceline - N Corner 04/02/2025 8 AM 11 Good Hangar Fenceline - NE Corner 04/02/2025 8 AM 11 Good Hangar Fenceline - S Side 04/02/2025 8 AM 13 Good Hangar Fenceline - SW Corner 04/02/2025 8 AM 13 Good Hangar Fenceline - SW Side 04/02/2025 8 AM 7 Good Hangar Fenceline - W Side 04/02/2025 8 AM 7 Good Legacy Road 04/02/2025 8 AM 8 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health VIE effects is increased for everyone. 425 to 07.. emergency FM . . . everyone more likely ..- affected. Thursday, April 3, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. Very Unhealthy Hazardous (355 to 424) (425-504) Columbus Square Park PeriodLocation 24-Hour Ending 04/03/2025 8 AM Particulate Matter 11 Level of Concern Good Hangar Fenceline - E Side 04/03/2025 8 AM 13 Good Hangar Fenceline - N Center 04/03/2025 8 AM 10 Good Hangar Fenceline - N Corner 04/03/2025 8 AM 9 Good Hangar Fenceline - NE Corner 04/03/2025 8 AM 10 Good Hangar Fenceline - S Side 04/03/2025 8 AM 13 Good Hangar Fenceline - SW Corner 04/03/2025 8 AM 12 Good Hangar Fenceline - SW Side 04/03/2025 8 AM 6 Good Hangar Fenceline - W Side 04/03/2025 8 AM 7 Good Legacy Road 04/03/2025 8 AM 7 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health VIE effects is increased for everyone. 425 to 07.. emergency FM . . . everyone more likely ..- affected. Friday, April 4, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. Very Unhealthy Hazardous (355 to 424) (425-504) Columbus Square Park PeriodLocation 24-Hour Ending 04/04/2025 8 AM Particulate Matter 15 Level of Concern Good Hangar Fenceline - E Side 04/04/2025 8 AM 12 Good Hangar Fenceline - N Center 04/04/2025 8 AM 10 Good Hangar Fenceline - N Corner 04/04/2025 8 AM 13 Good Hangar Fenceline - NE Corner 04/04/2025 8 AM 11 Good Hangar Fenceline - S Side 04/04/2025 8 AM 8 Good Hangar Fenceline - SW Corner 04/04/2025 8 AM 15 Good Hangar Fenceline - SW Side 04/04/2025 8 AM 7 Good Hangar Fenceline - W Side 04/04/2025 8 AM 12 Good Legacy Road 04/04/2025 8 AM 11 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. 425 to 17• • - •- • • • • • - likely • be -• Saturday, April 5, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. Very Unhealthy Hazardous (355 to 424) (425-504) Columbus Square Park PeriodLocation 24-Hour Ending 04/05/2025 8 AM Particulate Matter 11 Level of Concern Good Hangar Fenceline - E Side 04/05/2025 8 AM 13 Good Hangar Fenceline - N Center 04/05/2025 8 AM 10 Good Hangar Fenceline - N Corner 04/05/2025 8 AM 10 Good Hangar Fenceline - NE Corner 04/05/2025 8 AM 11 Good Hangar Fenceline - S Side 04/05/2025 8 AM 14 Good Hangar Fenceline - SW Corner 04/05/2025 8 AM 15 Good Hangar Fenceline - SW Side 04/05/2025 8 AM 8 Good Hangar Fenceline - W Side 04/05/2025 8 AM 7 Good Legacy Road 04/05/2025 8 AM 8 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. 425 to /74 . • emergency • • • • • - likely tobe affected. Sunday, April 6, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. ** Data gap due to instrument malfunction Very Unhealthy Hazardous (355 to 424) (425-504) Location Columbus Square Park Period Ending 04/06/2025 8 AM Matter 6 Level of Concern Good Hangar Fenceline - E Side 04/06/2025 8 AM 9 Good Hangar Fenceline - N Center 04/06/2025 8 AM 7 Good Hangar Fenceline - N Corner 04/06/2025 8 AM 8 Good Hangar Fenceline - NE Corner 04/06/2025 8 AM 9 Good Hangar Fenceline - S Side 04/06/2025 8 AM 12 Good Hangar Fenceline - SW Corner 04/06/2025 8 AM 12 Good Hangar Fenceline - SW Side 04/06/2025 8 AM 6 Good Hangar Fenceline - W Side 04/06/2025 8 AM 6 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. azardous 425 to 504 Health warning of emergency conditions: ever. . - likely ..- affected. Monday, April 7, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. Very Unhealthy Hazardous (355 to 424) (425-504) Columbus Square Park PeriodLocation 24-Hour Ending 04/07/2025 8 AM Particulate Matter 12 Level of Concern Good Hangar Fenceline - E Side 04/07/2025 8 AM 17 Good Hangar Fenceline - N Center 04/07/2025 8 AM 14 Good Hangar Fenceline - N Corner 04/07/2025 8 AM 12 Good Hangar Fenceline - NE Corner 04/07/2025 8 AM 15 Good Hangar Fenceline - S Side 04/07/2025 8 AM 16 Good Hangar Fenceline - SW Corner 04/07/2025 8 AM 20 Good Hangar Fenceline - SW Side 04/07/2025 8 AM 12 Good Hangar Fenceline - W Side 04/07/2025 8 AM 10 Good Legacy Road 04/07/2025 8 AM 13 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. 425 to 17• • - •- • • • • • - likely • be -• Tuesday, April 8, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. ** Data gap due to instrument malfunction. Very Unhealthy Hazardous (355 to 424) (425-504) Location Columbus Square Park Period Ending 04/08/2025 8 AM Matter ** Level of Concern ** Hangar Fenceline - E Side 04/08/2025 8 AM 17 Good Hangar Fenceline - N Center 04/08/2025 8 AM 14 Good Hangar Fenceline - N Corner 04/08/2025 8 AM 13 Good Hangar Fenceline - NE Corner 04/08/2025 8 AM 15 Good Hangar Fenceline - S Side 04/08/2025 8 AM 16 Good Hangar Fenceline - SW Corner 04/08/2025 8 AM 20 Good Hangar Fenceline - SW Side 04/08/2025 8 AM 11 Good Hangar Fenceline - W Side 04/08/2025 8 AM 10 Good Legacy Road 04/08/2025 8 AM 12 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health VIE effects is increased for everyone. 425 to 07.. emergency FM . . . everyone more likely ..- affected. Wednesday, April 9, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate Unhealthy for Unhealthy Very UnhealthyHazardous (0 to 54) (55 to 154) Sensitive Groups 155 to 254) (255 to 354) (355 to 424) (425-504) �( See below for further category descriptions. Columbus Square Park PeriodLocation 24-Hour Ending 04/09/2025 8 AM Particulate Matter 15 Level of Concern Good Hangar Fenceline - E Side 04/09/2025 8 AM 21 Good Hangar Fenceline - N Center 04/09/2025 8 AM 19 Good Hangar Fenceline - N Corner 04/09/2025 8 AM 15 Good Hangar Fenceline - NE Corner 04/09/2025 8 AM 19 Good Hangar Fenceline - S Side 04/09/2025 8 AM 17 Good Hangar Fenceline - SW Corner 04/09/2025 8 AM 25 Good Hangar Fenceline - SW Side 04/09/2025 8 AM 13 Good Hangar Fenceline - W Side 04/09/2025 8 AM 11 Good Legacy Road 04/09/2025 8 AM 16 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. 425 to /74 . • emergency • • • • • - likely tobe affected. Thursday, April 10, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. Very Unhealthy Hazardous (355 to 424) (425-504) Columbus Square Park PeriodLocation 24-Hour Ending 04/10/2025 8 AM Particulate Matter 16 Level of Concern Good Hangar Fenceline - E Side 04/10/2025 8 AM 21 Good Hangar Fenceline - N Center 04/10/2025 8 AM 19 Good Hangar Fenceline - N Corner 04/10/2025 8 AM 16 Good Hangar Fenceline - NE Corner 04/10/2025 8 AM 19 Good Hangar Fenceline - S Side 04/10/2025 8 AM 18 Good Hangar Fenceline - SW Corner 04/10/2025 8 AM 26 Good Hangar Fenceline - SW Side 04/10/2025 8 AM 14 Good Hangar Fenceline - W Side 04/10/2025 8 AM 12 Good Legacy Road 04/10/2025 8 AM 17 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health VIE effects is increased for everyone. 425 to 07.. emergency FM . . . everyone more likely ..- affected. Friday, April 11, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. ** Data gap due to instrument malfunction. Very Unhealthy Hazardous (355 to 424) (425-504) Location Columbus Square Park Period Ending 04/11/2025 8 AM Matter 19 Level of Concern Good Hangar Fenceline - E Side 04/11/2025 8 AM 24 Good Hangar Fenceline - N Center 04/11/2025 8 AM 22 Good Hangar Fenceline - N Corner 04/11/2025 8 AM 19 Good Hangar Fenceline - NE Corner 04/11/2025 8 AM 22 Good Hangar Fenceline - S Side 04/11/2025 8 AM 20 Good Hangar Fenceline - SW Corner 04/11/2025 8 AM 31 Good Hangar Fenceline - SW Side 04/11/2025 8 AM 16 Good Hangar Fenceline - W Side 04/11/2025 8 AM 15 Good Legacy Road 04/11/2025 8 AM 19 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. 425 to 17• • - •- • • • • • - likely • be -• Saturday, April 12, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate Unhealthy for Unhealthy Very Unhealthy • • (0 to 54) (55 to 154) Sensitive Groups 155 to 254) (255 to 354) (355 to 424) (425-504) �( See below for further category descriptions. ** Data gap due to instrument malfunction. Location Columbus Square Park 24-Hour Period Ending 04/12/2025 8 AM 17 Good Hangar Fenceline - E Side 04/12/2025 8 AM 23 Good Hangar Fenceline - N Center 04/12/2025 8 AM 21 Good Hangar Fenceline - N Corner 04/12/2025 8 AM 17 Good Hangar Fenceline - NE Corner 04/12/2025 8 AM 21 Good Hangar Fenceline - S Side 04/12/2025 8 AM 19 Good Hangar Fenceline - SW Corner 04/12/2025 8 AM 29 Good Hangar Fenceline - SW Side 04/12/2025 8 AM 15 Good Hangar Fenceline - W Side 04/12/2025 8 AM 14 Good Legacy Road 04/12/2025 8 AM 20 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. 425 to 17• • - •- • • • • • - likely • be -• Sunday, April 13, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. ** Data gap due to instrument malfunction. Very Unhealthy Hazardous (355 to 424) (425-504) Location Columbus Square Park Period Ending 04/13/2025 8 AM Matter ** Level of Concern ** Hangar Fenceline - E Side 04/13/2025 8 AM 28 Good Hangar Fenceline - N Center 04/13/2025 8 AM 26 Good Hangar Fenceline - N Corner 04/13/2025 8 AM 24 Good Hangar Fenceline - NE Corner 04/13/2025 8 AM 26 Good Hangar Fenceline - S Side 04/13/2025 8 AM 25 Good Hangar Fenceline - SW Corner 04/13/2025 8 AM 40 Good Hangar Fenceline - SW Side 04/13/2025 8 AM 19 Good Hangar Fenceline - W Side 04/13/2025 8 AM 20 Good Legacy Road 04/13/2025 8 AM 22 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health VIE effects is increased for everyone. 425 to 07.. emergency FM . . . everyone more likely ..- affected. Monday, April 14, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. ** Data gap due to instrument malfunction. Very Unhealthy Hazardous (355 to 424) (425-504) Location Columbus Square Park Period Ending 04/14/2025 8 AM Matter ** Level of Concern ** Hangar Fenceline - E Side 04/14/2025 8 AM 22 Good Hangar Fenceline - N Center 04/14/2025 8 AM 20 Good Hangar Fenceline - N Corner 04/14/2025 8 AM 16 Good Hangar Fenceline - NE Corner 04/14/2025 8 AM 20 Good Hangar Fenceline - S Side 04/14/2025 8 AM 20 Good Hangar Fenceline - SW Corner 04/14/2025 8 AM 27 Good Hangar Fenceline - SW Side 04/14/2025 8 AM 14 Good Hangar Fenceline - W Side 04/14/2025 8 AM 13 Good Legacy Road 04/14/2025 8 AM 17 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. 425 to 17• • - •- • • • • • - likely • be -• Tuesday, April 15, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. Very Unhealthy Hazardous (355 to 424) (425-504) Columbus Square Park PeriodLocation 24-Hour Ending 04/15/2025 8 AM Particulate Matter 16 Level of Concern Good Hangar Fenceline - E Side 04/15/2025 8 AM 21 Good Hangar Fenceline - N Center 04/15/2025 8 AM 19 Good Hangar Fenceline - N Corner 04/15/2025 8 AM 16 Good Hangar Fenceline - NE Corner 04/15/2025 8 AM 19 Good Hangar Fenceline - S Side 04/15/2025 8 AM 19 Good Hangar Fenceline - SW Corner 04/15/2025 8 AM 26 Good Hangar Fenceline - SW Side 04/15/2025 8 AM 13 Good Hangar Fenceline - W Side 04/15/2025 8 AM 13 Good Legacy Road 04/15/2025 8 AM 15 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. 425 to 17• • - •- • • • • • - likely • be -• Wednesday, April 16, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. Very Unhealthy Hazardous (355 to 424) (425-504) Columbus Square Park PeriodLocation 24-Hour Ending 04/16/2025 8 AM Particulate Matter 16 Level of Concern Good Hangar Fenceline - E Side 04/16/2025 8 AM 21 Good Hangar Fenceline - N Center 04/16/2025 8 AM 19 Good Hangar Fenceline - N Corner 04/16/2025 8 AM 16 Good Hangar Fenceline - NE Corner 04/16/2025 8 AM 19 Good Hangar Fenceline - S Side 04/16/2025 8 AM 19 Good Hangar Fenceline - SW Corner 04/16/2025 8 AM 26 Good Hangar Fenceline - SW Side 04/16/2025 8 AM 13 Good Hangar Fenceline - W Side 04/16/2025 8 AM 13 Good Legacy Road 04/16/2025 8 AM 15 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. 425 to 17• • - •- • • • • • - likely • be -• Thursday, April 17, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate Unhealthy for Unhealthy Very Unhealthy • • (0 to 54) (55 to 154) Sensitive Groups 155 to 254) (255 to 354) (355 to 424) (425-504) �( See below for further category descriptions. ** Data gap due to instrument malfunction. Location Columbus Square Park 24-Hour Period Ending 04/17/2025 8 AM 7 Good Hangar Fenceline - E Side 04/17/2025 8 AM 11 Good Hangar Fenceline - N Center 04/17/2025 8 AM 11 Good Hangar Fenceline - N Corner 04/17/2025 8 AM 8 Good Hangar Fenceline - NE Corner 04/17/2025 8 AM 11 Good Hangar Fenceline - S Side 04/17/2025 8 AM 12 Good Hangar Fenceline - SW Corner 04/17/2025 8 AM ** ** Hangar Fenceline - SW Side 04/17/2025 8 AM 6 Good Hangar Fenceline - W Side 04/17/2025 8 AM 6 Good Legacy Road 04/17/2025 8 AM 10 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health VIE effects is increased for everyone. 425 to 07.. emergency FM . . . everyone more likely ..- affected. Friday April 18, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. ** Data gap due to instrument malfunction. Very Unhealthy Hazardous (355 to 424) (425-504) Location Columbus Square Park Period Ending 04/18/2025 8 AM Matter 5 Level of Concern Good Hangar Fenceline - E Side 04/18/2025 8 AM 9 Good Hangar Fenceline - N Center 04/18/2025 8 AM 11 Good Hangar Fenceline - N Corner 04/18/2025 8 AM 6 Good Hangar Fenceline - NE Corner 04/18/2025 8 AM 9 Good Hangar Fenceline - S Side 04/18/2025 8 AM 11 Good Hangar Fenceline - SW Corner 04/18/2025 8 AM 5 Good Hangar Fenceline - SW Side 04/18/2025 8 AM 5 Good Hangar Fenceline - W Side 04/18/2025 8 AM 5 Good Legacy Road 04/18/2025 8 AM 10 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health VIE effects is increased for everyone. 425 to 07.. emergency FM . . . everyone more likely ..- affected. Saturday, April 19, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. Very Unhealthy Hazardous (355 to 424) (425-504) Columbus Square Park PeriodLocation 24-Hour Ending 04/19/2025 8 AM Particulate Matter 10 Level of Concern Good Hangar Fenceline - E Side 04/19/2025 8 AM 14 Good Hangar Fenceline - N Center 04/19/2025 8 AM 17 Good Hangar Fenceline - N Corner 04/19/2025 8 AM 10 Good Hangar Fenceline - NE Corner 04/19/2025 8 AM 13 Good Hangar Fenceline - S Side 04/19/2025 8 AM 14 Good Hangar Fenceline - SW Corner 04/19/2025 8 AM 8 Good Hangar Fenceline - SW Side 04/19/2025 8 AM 9 Good Hangar Fenceline - W Side 04/19/2025 8 AM 8 Good Legacy Road 04/19/2025 8 AM 15 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health VIE effects is increased for everyone. 425 to 07.. emergency FM . . . everyone more likely ..- affected. Sunday, April 20, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. Very Unhealthy Hazardous (355 to 424) (425-504) Columbus Square Park PeriodLocation 24-Hour Ending 04/20/2025 8 AM Particulate Matter 15 Level of Concern Good Hangar Fenceline - E Side 04/20/2025 8 AM 21 Good Hangar Fenceline - N Center 04/20/2025 8 AM 25 Good Hangar Fenceline - N Corner 04/20/2025 8 AM 16 Good Hangar Fenceline - NE Corner 04/20/2025 8 AM 19 Good Hangar Fenceline - S Side 04/20/2025 8 AM 19 Good Hangar Fenceline - SW Corner 04/20/2025 8 AM 15 Good Hangar Fenceline - SW Side 04/20/2025 8 AM 15 Good Hangar Fenceline - W Side 04/20/2025 8 AM 13 Good Legacy Road 04/20/2025 8 AM 22 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. 425 • 04 Health warning.emergencyT— more conditions:• - is likely • be affected. Monday, April 21, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. Very Unhealthy Hazardous (355 to 424) (425-504) Columbus Square Park PeriodLocation 24-Hour Ending 04/21/2025 8 AM Particulate Matter 22 Level of Concern Good Hangar Fenceline - E Side 04/21/2025 8 AM 29 Good Hangar Fenceline - N Center 04/21/2025 8 AM 34 Good Hangar Fenceline - N Corner 04/21/2025 8 AM 21 Good Hangar Fenceline - NE Corner 04/21/2025 8 AM 26 Good Hangar Fenceline - S Side 04/21/2025 8 AM 24 Good Hangar Fenceline - SW Corner 04/21/2025 8 AM 21 Good Hangar Fenceline - SW Side 04/21/2025 8 AM 20 Good Hangar Fenceline - W Side 04/21/2025 8 AM 18 Good Legacy Road 04/21/2025 8 AM 30 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. 425 • 04 Health warning.emergencyT— more conditions:• - is likely • be affected. Tuesday, April 22, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. ** Data gap due to instrument malfunction. Very Unhealthy Hazardous (355 to 424) (425-504) Location Columbus Square Park Period Ending 04/22/2025 8 AM Matter 19 Level of Concern Good Hangar Fenceline - E Side 04/22/2025 8 AM 24 Good Hangar Fenceline - N Center 04/22/2025 8 AM 29 Good Hangar Fenceline - N Corner 04/22/2025 8 AM 19 Good Hangar Fenceline - NE Corner 04/22/2025 8 AM 22 Good Hangar Fenceline - S Side 04/22/2025 8 AM 21 Good Hangar Fenceline - SW Corner 04/22/2025 8 AM 17 Good Hangar Fenceline - SW Side 04/22/2025 8 AM 17 Good Hangar Fenceline - W Side 04/22/2025 8 AM 15 Good Legacy Road 04/22/2025 8 AM 26 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. 425 • 04 Health warning.emergencyT— more conditions:• - is likely • be affected. Wednesday, April 23, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. Very Unhealthy Hazardous (355 to 424) (425-504) Columbus Square Park PeriodLocation 24-Hour Ending 04/23/2025 8 AM Particulate Matter 13 Level of Concern Good Hangar Fenceline - E Side 04/23/2025 8 AM 17 Good Hangar Fenceline - N Center 04/23/2025 8 AM 23 Good Hangar Fenceline - N Corner 04/23/2025 8 AM 14 Good Hangar Fenceline - NE Corner 04/23/2025 8 AM 17 Good Hangar Fenceline - S Side 04/23/2025 8 AM 18 Good Hangar Fenceline - SW Corner 04/23/2025 8 AM 12 Good Hangar Fenceline - SW Side 04/23/2025 8 AM 13 Good Hangar Fenceline - W Side 04/23/2025 8 AM 12 Good Legacy Road 04/23/2025 8 AM 21 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. 425 to 17• • - •- • • • • • - likely • be -• Thursday, April 24, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. ** Data gap due to instrument malfunction. Very Unhealthy Hazardous (355 to 424) (425-504) Location Columbus Square Park Period Ending 04/24/2025 8 AM Matter ** Level of Concern ** Hangar Fenceline - E Side 04/24/2025 8 AM 11 Good Hangar Fenceline - N Center 04/24/2025 8 AM 19 Good Hangar Fenceline - N Corner 04/24/2025 8 AM 9 Good Hangar Fenceline - NE Corner 04/24/2025 8 AM 11 Good Hangar Fenceline - S Side 04/24/2025 8 AM 13 Good Hangar Fenceline - SW Corner 04/24/2025 8 AM 7 Good Hangar Fenceline - SW Side 04/24/2025 8 AM 8 Good Hangar Fenceline - W Side 04/24/2025 8 AM 8 Good Legacy Road 04/24/2025 8 AM 16 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health VIE effects is increased for everyone. 425 to 07.. emergency FM . . . everyone more likely ..- affected. Friday, April 25, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. Very Unhealthy Hazardous (355 to 424) (425-504) Columbus Square Park PeriodLocation 24-Hour Ending 04/25/2025 8 AM Particulate Matter 11 Level of Concern Good Hangar Fenceline - E Side 04/25/2025 8 AM 15 Good Hangar Fenceline - N Center 04/25/2025 8 AM 23 Good Hangar Fenceline - N Corner 04/25/2025 8 AM 12 Good Hangar Fenceline - NE Corner 04/25/2025 8 AM 15 Good Hangar Fenceline - S Side 04/25/2025 8 AM 16 Good Hangar Fenceline - SW Corner 04/25/2025 8 AM 10 Good Hangar Fenceline - SW Side 04/25/2025 8 AM 11 Good Hangar Fenceline - W Side 04/25/2025 8 AM 10 Good Legacy Road 04/25/2025 8 AM 19 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health VIE effects is increased for everyone. 425 to 07.. emergency FM . . . everyone more likely ..- affected. Saturday, April 26, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. Very Unhealthy Hazardous (355 to 424) (425-504) Columbus Square Park PeriodLocation 24-Hour Ending 04/26/2025 8 AM Particulate Matter 6 Level of Concern Good Hangar Fenceline - E Side 04/26/2025 8 AM 7 Good Hangar Fenceline - N Center 04/26/2025 8 AM 17 Good Hangar Fenceline - N Corner 04/26/2025 8 AM 6 Good Hangar Fenceline - NE Corner 04/26/2025 8 AM 8 Good Hangar Fenceline - S Side 04/26/2025 8 AM 11 Good Hangar Fenceline - SW Corner 04/26/2025 8 AM 4 Good Hangar Fenceline - SW Side 04/26/2025 8 AM 5 Good Hangar Fenceline - W Side 04/26/2025 8 AM 5 Good Legacy Road 04/26/2025 8 AM 12 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health VIE effects is increased for everyone. 425 to 07.. emergency FM . . . everyone more likely ..- affected. Sunday, April 27, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. ** Data gap due to instrument malfunction. Very Unhealthy Hazardous (355 to 424) (425-504) Location Columbus Square Park Period Ending 04/27/2025 8 AM Matter 5 Level of Concern Good Hangar Fenceline - E Side 04/27/2025 8 AM 6 Good Hangar Fenceline - N Center 04/27/2025 8 AM ** ** Hangar Fenceline - N Corner 04/27/2025 8 AM 4 Good Hangar Fenceline - NE Corner 04/27/2025 8 AM ** ** Hangar Fenceline - S Side 04/27/2025 8 AM 10 Good Hangar Fenceline - SW Corner 04/27/2025 8 AM 2 Good Hangar Fenceline - SW Side 04/27/2025 8 AM 4 Good Hangar Fenceline - W Side 04/27/2025 8 AM 4 Good Legacy Road 04/27/2025 8 AM 10 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health VIE effects is increased for everyone. 425 to 07.. emergency FM . . . everyone more likely ..- affected. Monday, April 28, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. Very Unhealthy Hazardous (355 to 424) (425-504) Columbus Square Park PeriodLocation 24-Hour Ending 04/28/2025 8 AM Particulate Matter 4 Level of Concern Good Hangar Fenceline - E Side 04/28/2025 8 AM 6 Good Hangar Fenceline - N Center 04/28/2025 8 AM 5 Good Hangar Fenceline - N Corner 04/28/2025 8 AM 5 Good Hangar Fenceline - NE Corner 04/28/2025 8 AM 7 Good Hangar Fenceline - S Side 04/28/2025 8 AM 10 Good Hangar Fenceline - SW Corner 04/28/2025 8 AM 3 Good Hangar Fenceline - SW Side 04/28/2025 8 AM 4 Good Hangar Fenceline - W Side 04/28/2025 8 AM 4 Good Legacy Road 04/28/2025 8 AM 12 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. 425 to 17• • - •- • • • • • - likely • be -• Tuesday, April 29, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate Unhealthy for Unhealthy Very Unhealthy • • (0 to 54) (55 to 154) Sensitive Groups 155 to 254) (255 to 354) (355 to 424) (425-504) �( See below for further category descriptions. ** Data gap due to instrument malfunction. Location Columbus Square Park 24-Hour Period Ending 04/29/2025 8 AM 10 Good Hangar Fenceline - E Side 04/29/2025 8 AM 12 Good Hangar Fenceline - N Center 04/29/2025 8 AM 12 Good Hangar Fenceline - N Corner 04/29/2025 8 AM 10 Good Hangar Fenceline - NE Corner 04/29/2025 8 AM ** ** Hangar Fenceline - S Side 04/29/2025 8 AM ** ** Hangar Fenceline - SW Corner 04/29/2025 8 AM 8 Good Hangar Fenceline - SW Side 04/29/2025 8 AM 9 Good Hangar Fenceline - W Side 04/29/2025 8 AM 8 Good Legacy Road 04/29/2025 8 AM 17 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health effects is increased for everyone. 425 to 17• • - •- • • • • • - likely • be -• Wednesday, April 30, 2025 North Hangar Fire Incident I City of Tustin Air Quality Updates: Particulate Matter Air monitoring and sampling locations have been set up around the perimeter of the hangar and in surrounding communities to provide real-time information on Particulate Matter (PM) in the air. While the units are in place, an average reading for the last 24 hours will be provided for the public's reference. Any questions regarding these numbers should be directed to the call center at 714-426-2444. Monitoring Air Quality for Sensitive Individuals An environmental group contracted by the U.S. Navy is monitoring the air quality around the incident for any readings above 154 micrograms per cubic meter (ug/m3), which may cause individuals in sensitive groups to experience health effects. This is a moderate threshold that is less likely to affect the general public. What is Particulate Matter? "Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets that exists in the environment including pollen, dust, and soil. Typical particulate matter for the area ranges from 3 to 67 ug/m3. The concentration range is based on sampling results collected by South Coast AQMD in Anaheim, CA, which was the closest available dataset in proximity to the site. For more information about air quality and monitoring, visit the AirNow website at www.airnow.gov. Good Moderate (0 to 54) (55 to 154) Unhealthyfor Wnhealthy Sensitive Groups (255 to Unhealthy EL(155 to 254)354) See below for further category descriptions. Very Unhealthy Hazardous (355 to 424) (425-504) Columbus Square Park PeriodLocation 24-Hour Ending 04/30/2025 8 AM Particulate Matter 16 Level of Concern Good Hangar Fenceline - E Side 04/30/2025 8 AM 18 Good Hangar Fenceline - N Center 04/30/2025 8 AM 17 Good Hangar Fenceline - N Corner 04/30/2025 8 AM 15 Good Hangar Fenceline - NE Corner 04/30/2025 8 AM 20 Good Hangar Fenceline - S Side 04/30/2025 8 AM 19 Good Hangar Fenceline - SW Corner 04/30/2025 8 AM 15 Good Hangar Fenceline - SW Side 04/30/2025 8 AM 14 Good Hangar Fenceline - W Side 04/30/2025 8 AM 13 Good Legacy Road 04/30/2025 8 AM 23 Good Category Descriptions Color Green Good 0 to 54 Air quality is satisfactory, and air pollution poses little or no risk. Yellow Moderate 55 to 154 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. Orange Unhealthy for Sensitive 155 to 254 Members of sensitive groups may Groups experience health effects. The general public is less likely to be affected. Red Unhealthy 255 to 354 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. Purple Very Unhealthy 355 to 424 Health alert: The risk of health VIE effects is increased for everyone. 425 to 07.. emergency FM . . . everyone more likely ..- affected.