EnviroNearby

Placer County, California air quality history

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

46%
Good days in 2025
52
Median daily AQI, 2025
2
Days above 100 in 2025
365
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Placer, California on 365 days. 167 of those days (46%) were in the Good range, and the median daily AQI was 52. That median is higher than the typical monitored county in California (median 45.5 across 46 counties), and higher than the typical monitored U.S. county (40). The main pollutant was ozone on 216 days. Across the years with fuller monitoring, the share of Good days fell: an average of 60% in 1980–1982 versus 47% 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 220 of 366 days1980: Moderate 68 of 366 days1980: Unhealthy for Sensitive Groups 32 of 366 days1980: Unhealthy 37 of 366 days1980: Very Unhealthy 9 of 366 days19801981: Good 240 of 365 days1981: Moderate 46 of 365 days1981: Unhealthy for Sensitive Groups 39 of 365 days1981: Unhealthy 36 of 365 days1981: Very Unhealthy 4 of 365 days1982: Good 201 of 363 days1982: Moderate 100 of 363 days1982: Unhealthy for Sensitive Groups 41 of 363 days1982: Unhealthy 18 of 363 days1982: Very Unhealthy 3 of 363 days1983: Good 60 of 131 days1983: Moderate 34 of 131 days1983: Unhealthy for Sensitive Groups 27 of 131 days1983: Unhealthy 8 of 131 days1983: Very Unhealthy 2 of 131 days1984: Good 218 of 366 days1984: Moderate 87 of 366 days1984: Unhealthy for Sensitive Groups 36 of 366 days1984: Unhealthy 21 of 366 days1984: Very Unhealthy 4 of 366 days1985: Good 236 of 362 days1985: Moderate 67 of 362 days1985: Unhealthy for Sensitive Groups 36 of 362 days1985: Unhealthy 15 of 362 days1985: Very Unhealthy 8 of 362 days19851986: Good 214 of 363 days1986: Moderate 81 of 363 days1986: Unhealthy for Sensitive Groups 34 of 363 days1986: Unhealthy 29 of 363 days1986: Very Unhealthy 5 of 363 days1987: Good 192 of 365 days1987: Moderate 86 of 365 days1987: Unhealthy for Sensitive Groups 51 of 365 days1987: Unhealthy 28 of 365 days1987: Very Unhealthy 8 of 365 days1988: Good 169 of 344 days1988: Moderate 76 of 344 days1988: Unhealthy for Sensitive Groups 62 of 344 days1988: Unhealthy 28 of 344 days1988: Very Unhealthy 9 of 344 days1989: Good 192 of 365 days1989: Moderate 100 of 365 days1989: Unhealthy for Sensitive Groups 50 of 365 days1989: Unhealthy 23 of 365 days1990: Good 179 of 365 days1990: Moderate 89 of 365 days1990: Unhealthy for Sensitive Groups 59 of 365 days1990: Unhealthy 27 of 365 days1990: Very Unhealthy 11 of 365 days19901991: Good 203 of 334 days1991: Moderate 58 of 334 days1991: Unhealthy for Sensitive Groups 47 of 334 days1991: Unhealthy 23 of 334 days1991: Very Unhealthy 3 of 334 days1992: Good 200 of 365 days1992: Moderate 80 of 365 days1992: Unhealthy for Sensitive Groups 51 of 365 days1992: Unhealthy 29 of 365 days1992: Very Unhealthy 5 of 365 days1993: Good 219 of 365 days1993: Moderate 91 of 365 days1993: Unhealthy for Sensitive Groups 39 of 365 days1993: Unhealthy 14 of 365 days1993: Very Unhealthy 2 of 365 days1994: Good 183 of 365 days1994: Moderate 98 of 365 days1994: Unhealthy for Sensitive Groups 59 of 365 days1994: Unhealthy 19 of 365 days1994: Very Unhealthy 6 of 365 days1995: Good 213 of 365 days1995: Moderate 91 of 365 days1995: Unhealthy for Sensitive Groups 36 of 365 days1995: Unhealthy 21 of 365 days1995: Very Unhealthy 4 of 365 days19951996: Good 220 of 366 days1996: Moderate 73 of 366 days1996: Unhealthy for Sensitive Groups 50 of 366 days1996: Unhealthy 20 of 366 days1996: Very Unhealthy 3 of 366 days1997: Good 248 of 365 days1997: Moderate 86 of 365 days1997: Unhealthy for Sensitive Groups 27 of 365 days1997: Unhealthy 4 of 365 days1998: Good 240 of 365 days1998: Moderate 59 of 365 days1998: Unhealthy for Sensitive Groups 46 of 365 days1998: Unhealthy 16 of 365 days1998: Very Unhealthy 4 of 365 days1999: Good 168 of 365 days1999: Moderate 111 of 365 days1999: Unhealthy for Sensitive Groups 59 of 365 days1999: Unhealthy 25 of 365 days1999: Very Unhealthy 2 of 365 days2000: Good 213 of 366 days2000: Moderate 93 of 366 days2000: Unhealthy for Sensitive Groups 41 of 366 days2000: Unhealthy 18 of 366 days2000: Very Unhealthy 1 of 366 days20002001: Good 211 of 365 days2001: Moderate 93 of 365 days2001: Unhealthy for Sensitive Groups 37 of 365 days2001: Unhealthy 23 of 365 days2001: Very Unhealthy 1 of 365 days2002: Good 193 of 365 days2002: Moderate 91 of 365 days2002: Unhealthy for Sensitive Groups 56 of 365 days2002: Unhealthy 21 of 365 days2002: Very Unhealthy 4 of 365 days2003: Good 187 of 365 days2003: Moderate 122 of 365 days2003: Unhealthy for Sensitive Groups 41 of 365 days2003: Unhealthy 13 of 365 days2003: Very Unhealthy 2 of 365 days2004: Good 143 of 366 days2004: Moderate 150 of 366 days2004: Unhealthy for Sensitive Groups 59 of 366 days2004: Unhealthy 14 of 366 days2005: Good 102 of 365 days2005: Moderate 198 of 365 days2005: Unhealthy for Sensitive Groups 44 of 365 days2005: Unhealthy 19 of 365 days2005: Very Unhealthy 2 of 365 days20052006: Good 109 of 365 days2006: Moderate 171 of 365 days2006: Unhealthy for Sensitive Groups 53 of 365 days2006: Unhealthy 30 of 365 days2006: Very Unhealthy 2 of 365 days2007: Good 120 of 365 days2007: Moderate 200 of 365 days2007: Unhealthy for Sensitive Groups 42 of 365 days2007: Unhealthy 3 of 365 days2008: Good 126 of 366 days2008: Moderate 182 of 366 days2008: Unhealthy for Sensitive Groups 39 of 366 days2008: Unhealthy 16 of 366 days2008: Very Unhealthy 3 of 366 days2009: Good 128 of 365 days2009: Moderate 200 of 365 days2009: Unhealthy for Sensitive Groups 27 of 365 days2009: Unhealthy 10 of 365 days2010: Good 127 of 365 days2010: Moderate 208 of 365 days2010: Unhealthy for Sensitive Groups 26 of 365 days2010: Unhealthy 4 of 365 days20102011: Good 135 of 365 days2011: Moderate 191 of 365 days2011: Unhealthy for Sensitive Groups 33 of 365 days2011: Unhealthy 6 of 365 days2012: Good 145 of 366 days2012: Moderate 180 of 366 days2012: Unhealthy for Sensitive Groups 35 of 366 days2012: Unhealthy 6 of 366 days2013: Good 126 of 365 days2013: Moderate 222 of 365 days2013: Unhealthy for Sensitive Groups 13 of 365 days2013: Unhealthy 4 of 365 days2014: Good 116 of 365 days2014: Moderate 221 of 365 days2014: Unhealthy for Sensitive Groups 23 of 365 days2014: Unhealthy 3 of 365 days2014: Very Unhealthy 2 of 365 days2015: Good 179 of 365 days2015: Moderate 177 of 365 days2015: Unhealthy for Sensitive Groups 8 of 365 days2015: Unhealthy 1 of 365 days20152016: Good 187 of 366 days2016: Moderate 159 of 366 days2016: Unhealthy for Sensitive Groups 17 of 366 days2016: Unhealthy 3 of 366 days2017: Good 211 of 365 days2017: Moderate 145 of 365 days2017: Unhealthy for Sensitive Groups 7 of 365 days2017: Unhealthy 2 of 365 days2018: Good 213 of 365 days2018: Moderate 127 of 365 days2018: Unhealthy for Sensitive Groups 16 of 365 days2018: Unhealthy 7 of 365 days2018: Very Unhealthy 2 of 365 days2019: Good 198 of 365 days2019: Moderate 158 of 365 days2019: Unhealthy for Sensitive Groups 9 of 365 days2020: Good 130 of 366 days2020: Moderate 195 of 366 days2020: Unhealthy for Sensitive Groups 20 of 366 days2020: Unhealthy 15 of 366 days2020: Very Unhealthy 6 of 366 days20202021: Good 130 of 365 days2021: Moderate 187 of 365 days2021: Unhealthy for Sensitive Groups 30 of 365 days2021: Unhealthy 9 of 365 days2021: Very Unhealthy 6 of 365 days2021: Hazardous 3 of 365 days2022: Good 156 of 365 days2022: Moderate 185 of 365 days2022: Unhealthy for Sensitive Groups 15 of 365 days2022: Unhealthy 4 of 365 days2022: Very Unhealthy 3 of 365 days2022: Hazardous 2 of 365 days2023: Good 164 of 365 days2023: Moderate 193 of 365 days2023: Unhealthy for Sensitive Groups 8 of 365 days2024: Good 188 of 366 days2024: Moderate 151 of 366 days2024: Unhealthy for Sensitive Groups 27 of 366 days2025: Good 167 of 365 days2025: Moderate 196 of 365 days2025: Unhealthy for Sensitive Groups 2 of 365 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 year0501001502001980: 90th percentile AQI 1661981: 90th percentile AQI 1511982: 90th percentile AQI 1331983: 90th percentile AQI 1431984: 90th percentile AQI 1331985: 90th percentile AQI 1261986: 90th percentile AQI 1431987: 90th percentile AQI 1501988: 90th percentile AQI 1541989: 90th percentile AQI 1331990: 90th percentile AQI 1541991: 90th percentile AQI 1431992: 90th percentile AQI 1471993: 90th percentile AQI 1191994: 90th percentile AQI 1401995: 90th percentile AQI 1261996: 90th percentile AQI 1361997: 90th percentile AQI 1001998: 90th percentile AQI 1291999: 90th percentile AQI 1362000: 90th percentile AQI 1262001: 90th percentile AQI 1332002: 90th percentile AQI 1362003: 90th percentile AQI 1262004: 90th percentile AQI 1262005: 90th percentile AQI 1302006: 90th percentile AQI 1472007: 90th percentile AQI 1062008: 90th percentile AQI 1152009: 90th percentile AQI 1012010: 90th percentile AQI 972011: 90th percentile AQI 1012012: 90th percentile AQI 1052013: 90th percentile AQI 842014: 90th percentile AQI 972015: 90th percentile AQI 772016: 90th percentile AQI 802017: 90th percentile AQI 772018: 90th percentile AQI 842019: 90th percentile AQI 772020: 90th percentile AQI 1082021: 90th percentile AQI 1152022: 90th percentile AQI 902023: 90th percentile AQI 802024: 90th percentile AQI 932025: 90th percentile AQI 711980: Median AQI 441981: Median AQI 401982: Median AQI 471983: Median AQI 541984: Median AQI 441985: Median AQI 431986: Median AQI 441987: Median AQI 481988: Median AQI 511989: Median AQI 481990: Median AQI 511991: Median AQI 441992: Median AQI 471993: Median AQI 471994: Median AQI 501995: Median AQI 461996: Median AQI 441997: Median AQI 431998: Median AQI 431999: Median AQI 582000: Median AQI 472001: Median AQI 462002: Median AQI 492003: Median AQI 502004: Median AQI 602005: Median AQI 612006: Median AQI 642007: Median AQI 572008: Median AQI 582009: Median AQI 572010: Median AQI 552011: Median AQI 572012: Median AQI 542013: Median AQI 552014: Median AQI 572015: Median AQI 512016: Median AQI 502017: Median AQI 462018: Median AQI 462019: Median AQI 492020: Median AQI 572021: Median AQI 582022: Median AQI 542023: Median AQI 522024: Median AQI 502025: Median AQI 521980198519901995200020052010201520202025
  • 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
Ozone21659%
Fine particles (PM2.5)14941%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
202536516719620005271143Ozone
2024366188151270005093140Ozone
202336516419380005280143Ozone
2022365156185154325490442Ozone
20213651301873096358115692Ozone
202036613019520156057108247Ozone
201936519815890004977136Ozone
2018365213127167204684248Ozone
201736521114572004677156Ozone
2016366187159173005080166PM2.5
201536517917781005177189PM2.5
2014365116221233205797265Ozone
2013365126222134005584165PM2.5
20123661451803560054105170Ozone
20113651351913360057101172Ozone
2010365127208264005597200PM2.5
200936512820027100057101190Ozone
200836612618239163058115225Ozone
20073651202004230057106187Ozone
200636510917153302064147209Ozone
200536510219844192061130203PM2.5
200436614315059140060126192Ozone
200336518712241132050126206Ozone
20023651939156214049136210Ozone
20013652119337231046133202Ozone
20003662139341181047126202Ozone
199936516811159252058136208Ozone
19983652405946164043129215Ozone
1997365248862740043100179Ozone
19963662207350203044136205Ozone
19953652139136214046126215Ozone
19943651839859196050140213Ozone
19933652199139142047119216Ozone
19923652008051295047147218Ozone
19913342035847233044143210Ozone
199036517989592711051154234Ozone
198936519210050230048133190Ozone
19883441697662289051154214Ozone
19873651928651288048150217Ozone
19863632148134295044143219Ozone
19853622366736158043126223Ozone
19843662188736214044133207Ozone
198313160342782054143212Ozone
198236320110041183047133226Ozone
19813652404639364040151213Ozone
19803662206832379044166218Ozone

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