Processed on 2024-03-04 12:50:22 PST.


Disclaimer: Data presented here come from a variety of sources and do not represent official EPA measurements. Please visit AirNow for official measurements.


Cumulative exposure to smoke is an important public health metric. This report summarizes the cumulative number of days air quality monitors in California spent in each AQI category during the the month of August.

The tables below include only permanent monitors measuring PM2.5 and show cumulative exposure under existing NAAQS (National Ambient Air Quality Standards) and under the 2024 revised standards for PM2.5.

In the tables and plots below, ‘Old’ designates cumulative days calculated using the 2023 PM2.5 NAAQS while ‘New’ is calculated using the 2024 revised PM2.5 NAAQS. The impact of the NAAQS revision is quite clear.

August in California

August 2014 – 116 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1496 300 3 1 0 0 152
New 1158 638 3 1 0 0 152

August 2015 – 136 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1380 715 27 15 9 2 156
New 959 1136 26 15 9 3 156

August 2016 – 264 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1687 655 6 7 0 0 301
New 1145 1197 6 7 0 0 301

August 2017 – 165 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1511 1348 16 9 0 0 188
New 837 2021 16 10 0 0 188

August 2018 – 289 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1020 1483 202 100 9 0 258
New 571 1922 210 91 19 1 258

August 2019 – 166 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 2709 282 0 0 0 0 241
New 2154 837 0 0 0 0 241

August 2020 – 362 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1635 829 203 222 14 4 389
New 1211 1241 212 204 29 10 389

August 2021 – 220 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1669 1248 252 233 35 22 253
New 1086 1822 257 223 43 28 253

August 2022 – 237 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 2977 512 14 16 3 0 222
New 2321 1167 15 14 3 2 222

August 2023 – 437 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 3235 680 21 12 1 0 307
New 2435 1477 24 10 2 1 307