Processed on 2024-03-04 12:50:09 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 July.

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.

July in California

July 2014 – 116 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1528 235 7 2 0 0 116
New 1223 540 7 2 0 0 116

July 2015 – 136 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1906 182 0 0 0 0 152
New 1570 518 0 0 0 0 152

July 2016 – 264 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1771 418 2 2 0 0 399
New 1357 832 2 2 0 0 399

July 2017 – 165 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1959 817 15 8 0 0 273
New 1251 1525 15 8 0 0 273

July 2018 – 289 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1970 837 63 38 4 0 192
New 1397 1409 64 31 10 1 192

July 2019 – 166 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 2642 446 3 3 0 0 170
New 2003 1085 3 3 0 0 170

July 2020 – 362 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 2532 434 10 6 0 0 218
New 1932 1034 9 6 1 0 218

July 2021 – 220 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 2698 607 32 26 4 2 311
New 1929 1375 33 25 5 2 311

July 2022 – 237 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 3391 309 7 10 1 0 378
New 2792 908 7 10 0 1 378

July 2023 – 437 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 2999 913 10 12 1 0 353
New 2152 1760 10 11 2 0 353