EnviroNearby

Solano County, California air quality history

Daily Air Quality Index summaries from EPA monitors in Solano, California, 1980–2025.

99%
Good days in 2025
33
Median daily AQI, 2025
0
Days above 100 in 2025
356
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Solano, California on 356 days. 353 of those days (99%) were in the Good range, and the median daily AQI was 33. That median is lower than the typical monitored county in California (median 45.5 across 46 counties), and lower than the typical monitored U.S. county (40). The main pollutant was ozone on 355 days. Across the years with fuller monitoring, the share of Good days rose: an average of 77% in 1980–1982 versus 84% in 2023–2025.

How the days broke down each year

Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.

Share of monitored days in each AQI category, by year0%25%50%75%100%1980: Good 263 of 366 days1980: Moderate 86 of 366 days1980: Unhealthy for Sensitive Groups 12 of 366 days1980: Unhealthy 4 of 366 days1980: Very Unhealthy 1 of 366 days19801981: Good 288 of 365 days1981: Moderate 68 of 365 days1981: Unhealthy for Sensitive Groups 8 of 365 days1981: Unhealthy 1 of 365 days1982: Good 290 of 365 days1982: Moderate 63 of 365 days1982: Unhealthy for Sensitive Groups 11 of 365 days1982: Unhealthy 1 of 365 days1983: Good 313 of 365 days1983: Moderate 42 of 365 days1983: Unhealthy for Sensitive Groups 9 of 365 days1983: Unhealthy 1 of 365 days1984: Good 273 of 366 days1984: Moderate 78 of 366 days1984: Unhealthy for Sensitive Groups 11 of 366 days1984: Unhealthy 4 of 366 days1985: Good 297 of 365 days1985: Moderate 60 of 365 days1985: Unhealthy for Sensitive Groups 7 of 365 days1985: Unhealthy 1 of 365 days19851986: Good 284 of 365 days1986: Moderate 74 of 365 days1986: Unhealthy for Sensitive Groups 7 of 365 days1987: Good 260 of 365 days1987: Moderate 79 of 365 days1987: Unhealthy for Sensitive Groups 19 of 365 days1987: Unhealthy 7 of 365 days1988: Good 252 of 366 days1988: Moderate 89 of 366 days1988: Unhealthy for Sensitive Groups 22 of 366 days1988: Unhealthy 3 of 366 days1989: Good 274 of 365 days1989: Moderate 78 of 365 days1989: Unhealthy for Sensitive Groups 11 of 365 days1989: Unhealthy 2 of 365 days1990: Good 281 of 365 days1990: Moderate 78 of 365 days1990: Unhealthy for Sensitive Groups 5 of 365 days1990: Unhealthy 1 of 365 days19901991: Good 285 of 365 days1991: Moderate 74 of 365 days1991: Unhealthy for Sensitive Groups 5 of 365 days1991: Unhealthy 1 of 365 days1992: Good 308 of 366 days1992: Moderate 54 of 366 days1992: Unhealthy for Sensitive Groups 3 of 366 days1992: Unhealthy 1 of 366 days1993: Good 302 of 365 days1993: Moderate 57 of 365 days1993: Unhealthy for Sensitive Groups 4 of 365 days1993: Unhealthy 2 of 365 days1994: Good 321 of 365 days1994: Moderate 39 of 365 days1994: Unhealthy for Sensitive Groups 5 of 365 days1995: Good 308 of 365 days1995: Moderate 44 of 365 days1995: Unhealthy for Sensitive Groups 9 of 365 days1995: Unhealthy 4 of 365 days19951996: Good 289 of 366 days1996: Moderate 50 of 366 days1996: Unhealthy for Sensitive Groups 23 of 366 days1996: Unhealthy 4 of 366 days1997: Good 324 of 365 days1997: Moderate 34 of 365 days1997: Unhealthy for Sensitive Groups 7 of 365 days1998: Good 305 of 365 days1998: Moderate 33 of 365 days1998: Unhealthy for Sensitive Groups 20 of 365 days1998: Unhealthy 7 of 365 days1999: Good 263 of 365 days1999: Moderate 71 of 365 days1999: Unhealthy for Sensitive Groups 25 of 365 days1999: Unhealthy 5 of 365 days1999: Very Unhealthy 1 of 365 days2000: Good 274 of 366 days2000: Moderate 81 of 366 days2000: Unhealthy for Sensitive Groups 9 of 366 days2000: Unhealthy 2 of 366 days20002001: Good 291 of 365 days2001: Moderate 63 of 365 days2001: Unhealthy for Sensitive Groups 8 of 365 days2001: Unhealthy 3 of 365 days2002: Good 274 of 365 days2002: Moderate 72 of 365 days2002: Unhealthy for Sensitive Groups 17 of 365 days2002: Unhealthy 2 of 365 days2003: Good 292 of 365 days2003: Moderate 63 of 365 days2003: Unhealthy for Sensitive Groups 10 of 365 days2004: Good 147 of 366 days2004: Moderate 202 of 366 days2004: Unhealthy for Sensitive Groups 16 of 366 days2004: Unhealthy 1 of 366 days2005: Good 182 of 365 days2005: Moderate 168 of 365 days2005: Unhealthy for Sensitive Groups 15 of 365 days20052006: Good 136 of 365 days2006: Moderate 209 of 365 days2006: Unhealthy for Sensitive Groups 17 of 365 days2006: Unhealthy 3 of 365 days2007: Good 155 of 365 days2007: Moderate 192 of 365 days2007: Unhealthy for Sensitive Groups 18 of 365 days2008: Good 102 of 366 days2008: Moderate 241 of 366 days2008: Unhealthy for Sensitive Groups 19 of 366 days2008: Unhealthy 4 of 366 days2009: Good 200 of 365 days2009: Moderate 156 of 365 days2009: Unhealthy for Sensitive Groups 9 of 365 days2010: Good 242 of 365 days2010: Moderate 119 of 365 days2010: Unhealthy for Sensitive Groups 4 of 365 days20102011: Good 199 of 365 days2011: Moderate 157 of 365 days2011: Unhealthy for Sensitive Groups 9 of 365 days2012: Good 208 of 366 days2012: Moderate 153 of 366 days2012: Unhealthy for Sensitive Groups 5 of 366 days2013: Good 161 of 365 days2013: Moderate 193 of 365 days2013: Unhealthy for Sensitive Groups 11 of 365 days2014: Good 171 of 365 days2014: Moderate 191 of 365 days2014: Unhealthy for Sensitive Groups 3 of 365 days2015: Good 186 of 365 days2015: Moderate 175 of 365 days2015: Unhealthy for Sensitive Groups 4 of 365 days20152016: Good 213 of 366 days2016: Moderate 151 of 366 days2016: Unhealthy for Sensitive Groups 2 of 366 days2017: Good 173 of 365 days2017: Moderate 182 of 365 days2017: Unhealthy for Sensitive Groups 5 of 365 days2017: Unhealthy 5 of 365 days2018: Good 184 of 365 days2018: Moderate 166 of 365 days2018: Unhealthy for Sensitive Groups 3 of 365 days2018: Unhealthy 11 of 365 days2018: Very Unhealthy 1 of 365 days2019: Good 226 of 365 days2019: Moderate 138 of 365 days2019: Unhealthy for Sensitive Groups 1 of 365 days2020: Good 183 of 366 days2020: Moderate 167 of 366 days2020: Unhealthy for Sensitive Groups 9 of 366 days2020: Unhealthy 6 of 366 days2020: Very Unhealthy 1 of 366 days20202021: Good 215 of 365 days2021: Moderate 147 of 365 days2021: Unhealthy for Sensitive Groups 3 of 365 days2022: Good 235 of 365 days2022: Moderate 130 of 365 days2023: Good 275 of 365 days2023: Moderate 89 of 365 days2023: Unhealthy for Sensitive Groups 1 of 365 days2024: Good 279 of 366 days2024: Moderate 86 of 366 days2024: Unhealthy for Sensitive Groups 1 of 366 days2025: Good 353 of 356 days2025: Moderate 3 of 356 days2025
  • Good
  • Moderate
  • Unhealthy for Sensitive Groups
  • Unhealthy
  • Very Unhealthy
  • Hazardous

Typical and high-end AQI over time

The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.

Median and 90th-percentile daily AQI, by year0501001980: 90th percentile AQI 751981: 90th percentile AQI 681982: 90th percentile AQI 681983: 90th percentile AQI 651984: 90th percentile AQI 791985: 90th percentile AQI 681986: 90th percentile AQI 741987: 90th percentile AQI 891988: 90th percentile AQI 791989: 90th percentile AQI 741990: 90th percentile AQI 681991: 90th percentile AQI 681992: 90th percentile AQI 571993: 90th percentile AQI 601994: 90th percentile AQI 541995: 90th percentile AQI 611996: 90th percentile AQI 771997: 90th percentile AQI 531998: 90th percentile AQI 801999: 90th percentile AQI 902000: 90th percentile AQI 692001: 90th percentile AQI 672002: 90th percentile AQI 772003: 90th percentile AQI 632004: 90th percentile AQI 882005: 90th percentile AQI 802006: 90th percentile AQI 872007: 90th percentile AQI 842008: 90th percentile AQI 882009: 90th percentile AQI 802010: 90th percentile AQI 682011: 90th percentile AQI 772012: 90th percentile AQI 692013: 90th percentile AQI 762014: 90th percentile AQI 692015: 90th percentile AQI 742016: 90th percentile AQI 652017: 90th percentile AQI 732018: 90th percentile AQI 692019: 90th percentile AQI 642020: 90th percentile AQI 772021: 90th percentile AQI 662022: 90th percentile AQI 672023: 90th percentile AQI 572024: 90th percentile AQI 582025: 90th percentile AQI 421980: Median AQI 381981: Median AQI 381982: Median AQI 381983: Median AQI 341984: Median AQI 381985: Median AQI 381986: Median AQI 381987: Median AQI 421988: Median AQI 431989: Median AQI 391990: Median AQI 381991: Median AQI 381992: Median AQI 371993: Median AQI 381994: Median AQI 361995: Median AQI 361996: Median AQI 391997: Median AQI 361998: Median AQI 361999: Median AQI 412000: Median AQI 382001: Median AQI 382002: Median AQI 392003: Median AQI 392004: Median AQI 542005: Median AQI 512006: Median AQI 552007: Median AQI 522008: Median AQI 572009: Median AQI 482010: Median AQI 422011: Median AQI 472012: Median AQI 462013: Median AQI 532014: Median AQI 512015: Median AQI 502016: Median AQI 472017: Median AQI 522018: Median AQI 502019: Median AQI 452020: Median AQI 512021: Median AQI 442022: Median AQI 432023: Median AQI 402024: Median AQI 392025: Median AQI 331980198519901995200020052010201520202025
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2025

On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.

PollutantDays as main pollutantShare of monitored days
Ozone355100%
Coarse particles (PM10)1<1%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
202535635330000334261Ozone
20243662798610003958107Ozone
20233652758910004057105Ozone
20223652351300000436793Ozone
202136521514730004466126PM2.5
202036618316796105177228PM2.5
201936522613810004564119PM2.5
2018365184166311105069272PM2.5
201736517318255005273184PM2.5
201636621315120004765105PM2.5
201536518617540005074118PM2.5
201436517119130005169124PM2.5
2013365161193110005376132PM2.5
201236620815350004669140PM2.5
201136519915790004777147PM2.5
201036524211940004268136Ozone
200936520015690004880150PM2.5
2008366102241194005788169PM2.5
2007365155192180005284126PM2.5
2006365136209173005587154PM2.5
2005365182168150005180145PM2.5
2004366147202161005488154PM2.5
200336529263100003963136Ozone
200236527472172003977163Ozone
20013652916383003867175Ozone
20003662748192003869154Ozone
199936526371255104190201Ozone
199836530533207003680190Ozone
19973653243470003653143Ozone
199636628950234003977190Ozone
19953653084494003661185Ozone
19943653213950003654140Ozone
19933653025742003860177Ozone
19923663085431003757151Ozone
19913652857451003868154Ozone
19903652817851003868156Ozone
198936527478112003974190Ozone
198836625289223004379169Ozone
198736526079197004289192Ozone
19863652847470003874123Ozone
19853652976071003868154Ozone
198436627378114003879174Ozone
19833653134291003465179Ozone
198236529063111003868156Ozone
19813652886881003868151Ozone
198036626386124103875205Ozone

What this data can and can’t tell you

It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.

It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.

Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.

Counties in California with a similar median AQI in 2025

All monitored counties in California

Source: U.S. EPA AirData, “Annual AQI by County” files for 1980–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem