EnviroNearby

Calaveras County, California air quality history

Daily Air Quality Index summaries from EPA monitors in Calaveras, California, 1994–2025.

82%
Good days in 2025
40
Median daily AQI, 2025
0
Days above 100 in 2025
359
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Calaveras, California on 359 days. 295 of those days (82%) were in the Good range, and the median daily AQI was 40. That median is lower than the typical monitored county in California (median 45.5 across 46 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was ozone on 258 days. Across the years with fuller monitoring, the share of Good days rose: an average of 56% in 1994–1996 versus 78% 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%1994: Good 106 of 250 days1994: Moderate 57 of 250 days1994: Unhealthy for Sensitive Groups 54 of 250 days1994: Unhealthy 32 of 250 days1994: Very Unhealthy 1 of 250 days19941995: Good 226 of 365 days1995: Moderate 82 of 365 days1995: Unhealthy for Sensitive Groups 39 of 365 days1995: Unhealthy 17 of 365 days1995: Very Unhealthy 1 of 365 days1996: Good 225 of 360 days1996: Moderate 68 of 360 days1996: Unhealthy for Sensitive Groups 49 of 360 days1996: Unhealthy 16 of 360 days1996: Very Unhealthy 2 of 360 days1997: Good 238 of 365 days1997: Moderate 95 of 365 days1997: Unhealthy for Sensitive Groups 29 of 365 days1997: Unhealthy 2 of 365 days1997: Very Unhealthy 1 of 365 days1998: Good 240 of 365 days1998: Moderate 59 of 365 days1998: Unhealthy for Sensitive Groups 39 of 365 days1998: Unhealthy 24 of 365 days1998: Very Unhealthy 3 of 365 days1999: Good 192 of 365 days1999: Moderate 108 of 365 days1999: Unhealthy for Sensitive Groups 49 of 365 days1999: Unhealthy 15 of 365 days1999: Very Unhealthy 1 of 365 days19992000: Good 244 of 364 days2000: Moderate 72 of 364 days2000: Unhealthy for Sensitive Groups 34 of 364 days2000: Unhealthy 14 of 364 days2001: Good 222 of 365 days2001: Moderate 98 of 365 days2001: Unhealthy for Sensitive Groups 41 of 365 days2001: Unhealthy 4 of 365 days2002: Good 200 of 365 days2002: Moderate 108 of 365 days2002: Unhealthy for Sensitive Groups 45 of 365 days2002: Unhealthy 11 of 365 days2002: Very Unhealthy 1 of 365 days2003: Good 206 of 365 days2003: Moderate 93 of 365 days2003: Unhealthy for Sensitive Groups 50 of 365 days2003: Unhealthy 16 of 365 days2004: Good 219 of 363 days2004: Moderate 116 of 363 days2004: Unhealthy for Sensitive Groups 24 of 363 days2004: Unhealthy 4 of 363 days20042005: Good 243 of 365 days2005: Moderate 78 of 365 days2005: Unhealthy for Sensitive Groups 38 of 365 days2005: Unhealthy 6 of 365 days2006: Good 227 of 364 days2006: Moderate 91 of 364 days2006: Unhealthy for Sensitive Groups 34 of 364 days2006: Unhealthy 11 of 364 days2006: Very Unhealthy 1 of 364 days2007: Good 248 of 359 days2007: Moderate 97 of 359 days2007: Unhealthy for Sensitive Groups 14 of 359 days2008: Good 220 of 361 days2008: Moderate 109 of 361 days2008: Unhealthy for Sensitive Groups 26 of 361 days2008: Unhealthy 5 of 361 days2008: Very Unhealthy 1 of 361 days2009: Good 262 of 364 days2009: Moderate 71 of 364 days2009: Unhealthy for Sensitive Groups 31 of 364 days20092010: Good 249 of 365 days2010: Moderate 103 of 365 days2010: Unhealthy for Sensitive Groups 12 of 365 days2010: Unhealthy 1 of 365 days2011: Good 164 of 364 days2011: Moderate 189 of 364 days2011: Unhealthy for Sensitive Groups 11 of 364 days2012: Good 213 of 366 days2012: Moderate 140 of 366 days2012: Unhealthy for Sensitive Groups 12 of 366 days2012: Unhealthy 1 of 366 days2013: Good 172 of 364 days2013: Moderate 190 of 364 days2013: Unhealthy for Sensitive Groups 2 of 364 days2014: Good 209 of 361 days2014: Moderate 148 of 361 days2014: Unhealthy for Sensitive Groups 4 of 361 days20142015: Good 216 of 365 days2015: Moderate 127 of 365 days2015: Unhealthy for Sensitive Groups 18 of 365 days2015: Unhealthy 1 of 365 days2015: Very Unhealthy 1 of 365 days2015: Hazardous 2 of 365 days2016: Good 195 of 366 days2016: Moderate 149 of 366 days2016: Unhealthy for Sensitive Groups 22 of 366 days2017: Good 118 of 354 days2017: Moderate 222 of 354 days2017: Unhealthy for Sensitive Groups 12 of 354 days2017: Unhealthy 2 of 354 days2018: Good 52 of 364 days2018: Moderate 292 of 364 days2018: Unhealthy for Sensitive Groups 14 of 364 days2018: Unhealthy 6 of 364 days2019: Good 288 of 360 days2019: Moderate 71 of 360 days2019: Unhealthy for Sensitive Groups 1 of 360 days20192020: Good 206 of 364 days2020: Moderate 135 of 364 days2020: Unhealthy for Sensitive Groups 10 of 364 days2020: Unhealthy 12 of 364 days2020: Very Unhealthy 1 of 364 days2021: Good 220 of 364 days2021: Moderate 135 of 364 days2021: Unhealthy for Sensitive Groups 6 of 364 days2021: Unhealthy 3 of 364 days2022: Good 286 of 364 days2022: Moderate 77 of 364 days2022: Unhealthy for Sensitive Groups 1 of 364 days2023: Good 292 of 365 days2023: Moderate 72 of 365 days2023: Unhealthy for Sensitive Groups 1 of 365 days2024: Good 261 of 359 days2024: Moderate 90 of 359 days2024: Unhealthy for Sensitive Groups 8 of 359 days20242025: Good 295 of 359 days2025: Moderate 64 of 359 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 year0501001502001994: 90th percentile AQI 1561995: 90th percentile AQI 1191996: 90th percentile AQI 1291997: 90th percentile AQI 1001998: 90th percentile AQI 1291999: 90th percentile AQI 1292000: 90th percentile AQI 1152001: 90th percentile AQI 1052002: 90th percentile AQI 1262003: 90th percentile AQI 1222004: 90th percentile AQI 932005: 90th percentile AQI 1052006: 90th percentile AQI 1082007: 90th percentile AQI 802008: 90th percentile AQI 932009: 90th percentile AQI 932010: 90th percentile AQI 842011: 90th percentile AQI 872012: 90th percentile AQI 872013: 90th percentile AQI 662014: 90th percentile AQI 712015: 90th percentile AQI 902016: 90th percentile AQI 872017: 90th percentile AQI 872018: 90th percentile AQI 872019: 90th percentile AQI 602020: 90th percentile AQI 792021: 90th percentile AQI 772022: 90th percentile AQI 582023: 90th percentile AQI 562024: 90th percentile AQI 742025: 90th percentile AQI 571994: Median AQI 771995: Median AQI 431996: Median AQI 421997: Median AQI 431998: Median AQI 431999: Median AQI 502000: Median AQI 392001: Median AQI 442002: Median AQI 482003: Median AQI 462004: Median AQI 452005: Median AQI 442006: Median AQI 432007: Median AQI 432008: Median AQI 452009: Median AQI 422010: Median AQI 442011: Median AQI 522012: Median AQI 472013: Median AQI 512014: Median AQI 472015: Median AQI 472016: Median AQI 492017: Median AQI 572018: Median AQI 582019: Median AQI 432020: Median AQI 482021: Median AQI 462022: Median AQI 412023: Median AQI 402024: Median AQI 422025: Median AQI 4019941999200420092014201920242025
  • 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
Ozone25872%
Fine particles (PM2.5)9928%
Coarse particles (PM10)21%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253592956400004057100Ozone
20243592619080004274129Ozone
20233652927210004056101Ozone
20223642867710004158115Ozone
202136422013563004677178Ozone
20203642061351012104879210Ozone
20193602887110004360108Ozone
201836452292146005887160PM2.5
2017354118222122005787172Ozone
2016366195149220004987150Ozone
2015365216127181124790390Ozone
201436120914840004771115Ozone
201336417219020005166119PM2.5
2012366213140121004787156Ozone
2011364164189110005287143Ozone
2010365249103121004484154Ozone
200936426271310004293136Ozone
2008361220109265104593202Ozone
200735924897140004380143Ozone
20063642279134111043108201Ozone
2005365243783860044105182Ozone
2004363219116244004593156Ozone
20033652069350160046122179Ozone
200236520010845111048126203Ozone
2001365222984140044105161Ozone
20003642447234140039115200Ozone
199936519210849151050129201Ozone
19983652405939243043129204Ozone
1997365238952921043100207Ozone
19963602256849162042129207Ozone
19953652268239171043119202Ozone
19942501065754321077156203Ozone

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 1994–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem