EnviroNearby

San Benito County, California air quality history

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

92%
Good days in 2025
39
Median daily AQI, 2025
0
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 San Benito, California on 365 days. 334 of those days (92%) were in the Good range, and the median daily AQI was 39. 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 310 days. Across the years with fuller monitoring, the share of Good days held roughly steady: an average of 83% in 1980–1982 versus 83% 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 303 of 364 days1980: Moderate 46 of 364 days1980: Unhealthy for Sensitive Groups 11 of 364 days1980: Unhealthy 3 of 364 days1980: Very Unhealthy 1 of 364 days19801981: Good 300 of 365 days1981: Moderate 49 of 365 days1981: Unhealthy for Sensitive Groups 12 of 365 days1981: Unhealthy 2 of 365 days1981: Very Unhealthy 2 of 365 days1982: Good 299 of 363 days1982: Moderate 53 of 363 days1982: Unhealthy for Sensitive Groups 11 of 363 days1983: Good 303 of 362 days1983: Moderate 48 of 362 days1983: Unhealthy for Sensitive Groups 8 of 362 days1983: Unhealthy 3 of 362 days1984: Good 300 of 358 days1984: Moderate 45 of 358 days1984: Unhealthy for Sensitive Groups 13 of 358 days1985: Good 290 of 356 days1985: Moderate 50 of 356 days1985: Unhealthy for Sensitive Groups 12 of 356 days1985: Unhealthy 4 of 356 days19851986: Good 301 of 353 days1986: Moderate 44 of 353 days1986: Unhealthy for Sensitive Groups 8 of 353 days1987: Good 198 of 365 days1987: Moderate 85 of 365 days1987: Unhealthy for Sensitive Groups 58 of 365 days1987: Unhealthy 22 of 365 days1987: Very Unhealthy 2 of 365 days1988: Good 230 of 365 days1988: Moderate 90 of 365 days1988: Unhealthy for Sensitive Groups 40 of 365 days1988: Unhealthy 5 of 365 days1989: Good 240 of 363 days1989: Moderate 97 of 363 days1989: Unhealthy for Sensitive Groups 25 of 363 days1989: Unhealthy 1 of 363 days1990: Good 247 of 365 days1990: Moderate 92 of 365 days1990: Unhealthy for Sensitive Groups 23 of 365 days1990: Unhealthy 3 of 365 days19901991: Good 235 of 362 days1991: Moderate 94 of 362 days1991: Unhealthy for Sensitive Groups 30 of 362 days1991: Unhealthy 2 of 362 days1991: Very Unhealthy 1 of 362 days1992: Good 261 of 366 days1992: Moderate 78 of 366 days1992: Unhealthy for Sensitive Groups 25 of 366 days1992: Unhealthy 2 of 366 days1993: Good 255 of 365 days1993: Moderate 82 of 365 days1993: Unhealthy for Sensitive Groups 26 of 365 days1993: Unhealthy 2 of 365 days1994: Good 256 of 365 days1994: Moderate 87 of 365 days1994: Unhealthy for Sensitive Groups 22 of 365 days1995: Good 262 of 364 days1995: Moderate 70 of 364 days1995: Unhealthy for Sensitive Groups 30 of 364 days1995: Unhealthy 2 of 364 days19951996: Good 251 of 366 days1996: Moderate 68 of 366 days1996: Unhealthy for Sensitive Groups 40 of 366 days1996: Unhealthy 7 of 366 days1997: Good 267 of 365 days1997: Moderate 82 of 365 days1997: Unhealthy for Sensitive Groups 15 of 365 days1997: Unhealthy 1 of 365 days1998: Good 279 of 365 days1998: Moderate 55 of 365 days1998: Unhealthy for Sensitive Groups 27 of 365 days1998: Unhealthy 4 of 365 days1999: Good 233 of 363 days1999: Moderate 106 of 363 days1999: Unhealthy for Sensitive Groups 24 of 363 days2000: Good 276 of 364 days2000: Moderate 66 of 364 days2000: Unhealthy for Sensitive Groups 22 of 364 days20002001: Good 270 of 364 days2001: Moderate 74 of 364 days2001: Unhealthy for Sensitive Groups 18 of 364 days2001: Unhealthy 2 of 364 days2002: Good 254 of 365 days2002: Moderate 77 of 365 days2002: Unhealthy for Sensitive Groups 30 of 365 days2002: Unhealthy 4 of 365 days2003: Good 255 of 365 days2003: Moderate 90 of 365 days2003: Unhealthy for Sensitive Groups 19 of 365 days2003: Unhealthy 1 of 365 days2004: Good 284 of 366 days2004: Moderate 71 of 366 days2004: Unhealthy for Sensitive Groups 11 of 366 days2005: Good 296 of 365 days2005: Moderate 65 of 365 days2005: Unhealthy for Sensitive Groups 4 of 365 days20052006: Good 276 of 365 days2006: Moderate 70 of 365 days2006: Unhealthy for Sensitive Groups 17 of 365 days2006: Unhealthy 2 of 365 days2007: Good 257 of 365 days2007: Moderate 91 of 365 days2007: Unhealthy for Sensitive Groups 17 of 365 days2008: Good 235 of 364 days2008: Moderate 103 of 364 days2008: Unhealthy for Sensitive Groups 22 of 364 days2008: Unhealthy 4 of 364 days2009: Good 288 of 365 days2009: Moderate 70 of 365 days2009: Unhealthy for Sensitive Groups 7 of 365 days2010: Good 288 of 365 days2010: Moderate 70 of 365 days2010: Unhealthy for Sensitive Groups 7 of 365 days20102011: Good 277 of 365 days2011: Moderate 86 of 365 days2011: Unhealthy for Sensitive Groups 2 of 365 days2012: Good 272 of 366 days2012: Moderate 86 of 366 days2012: Unhealthy for Sensitive Groups 8 of 366 days2013: Good 270 of 365 days2013: Moderate 90 of 365 days2013: Unhealthy for Sensitive Groups 5 of 365 days2014: Good 286 of 365 days2014: Moderate 75 of 365 days2014: Unhealthy for Sensitive Groups 4 of 365 days2015: Good 303 of 365 days2015: Moderate 62 of 365 days20152016: Good 298 of 366 days2016: Moderate 63 of 366 days2016: Unhealthy for Sensitive Groups 5 of 366 days2017: Good 284 of 365 days2017: Moderate 79 of 365 days2017: Unhealthy for Sensitive Groups 2 of 365 days2018: Good 270 of 365 days2018: Moderate 84 of 365 days2018: Unhealthy for Sensitive Groups 11 of 365 days2019: Good 318 of 365 days2019: Moderate 47 of 365 days2020: Good 271 of 366 days2020: Moderate 78 of 366 days2020: Unhealthy for Sensitive Groups 8 of 366 days2020: Unhealthy 9 of 366 days20202021: Good 295 of 365 days2021: Moderate 70 of 365 days2022: Good 297 of 365 days2022: Moderate 68 of 365 days2023: Good 316 of 365 days2023: Moderate 48 of 365 days2023: Unhealthy for Sensitive Groups 1 of 365 days2024: Good 260 of 366 days2024: Moderate 105 of 366 days2024: Unhealthy for Sensitive Groups 1 of 366 days2025: Good 334 of 365 days2025: Moderate 31 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 year0501001501980: 90th percentile AQI 681981: 90th percentile AQI 711982: 90th percentile AQI 711983: 90th percentile AQI 671984: 90th percentile AQI 611985: 90th percentile AQI 741986: 90th percentile AQI 671987: 90th percentile AQI 1401988: 90th percentile AQI 1081989: 90th percentile AQI 931990: 90th percentile AQI 971991: 90th percentile AQI 971992: 90th percentile AQI 871993: 90th percentile AQI 901994: 90th percentile AQI 901995: 90th percentile AQI 931996: 90th percentile AQI 1151997: 90th percentile AQI 771998: 90th percentile AQI 931999: 90th percentile AQI 872000: 90th percentile AQI 872001: 90th percentile AQI 842002: 90th percentile AQI 1002003: 90th percentile AQI 902004: 90th percentile AQI 772005: 90th percentile AQI 712006: 90th percentile AQI 802007: 90th percentile AQI 802008: 90th percentile AQI 932009: 90th percentile AQI 672010: 90th percentile AQI 602011: 90th percentile AQI 612012: 90th percentile AQI 712013: 90th percentile AQI 642014: 90th percentile AQI 612015: 90th percentile AQI 582016: 90th percentile AQI 612017: 90th percentile AQI 642018: 90th percentile AQI 632019: 90th percentile AQI 522020: 90th percentile AQI 682021: 90th percentile AQI 552022: 90th percentile AQI 572023: 90th percentile AQI 542024: 90th percentile AQI 582025: 90th percentile AQI 501980: Median AQI 341981: Median AQI 371982: Median AQI 371983: Median AQI 351984: Median AQI 351985: Median AQI 371986: Median AQI 371987: Median AQI 471988: Median AQI 441989: Median AQI 441990: Median AQI 441991: Median AQI 461992: Median AQI 401993: Median AQI 421994: Median AQI 421995: Median AQI 421996: Median AQI 431997: Median AQI 441998: Median AQI 421999: Median AQI 452000: Median AQI 402001: Median AQI 422002: Median AQI 432003: Median AQI 432004: Median AQI 412005: Median AQI 402006: Median AQI 422007: Median AQI 432008: Median AQI 462009: Median AQI 412010: Median AQI 412011: Median AQI 432012: Median AQI 422013: Median AQI 442014: Median AQI 422015: Median AQI 402016: Median AQI 392017: Median AQI 412018: Median AQI 422019: Median AQI 392020: Median AQI 412021: Median AQI 412022: Median AQI 422023: Median AQI 402024: Median AQI 432025: Median AQI 391980198519901995200020052010201520202025
  • 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
Ozone31085%
Fine particles (PM2.5)5515%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2025365334310000395071Ozone
202436626010510004358105Ozone
20233653164810004054111Ozone
2022365297680000425797Ozone
20213652957000004155100Ozone
20203662717889004168174Ozone
2019365318470000395290Ozone
201836527084110004263143Ozone
20173652847920004164117Ozone
20163662986350003961126Ozone
2015365303620000405893Ozone
20143652867540004261115Ozone
20133652709050004464112Ozone
20123662728680004271133Ozone
20113652778620004361108Ozone
20103652887070004160126Ozone
20093652887070004167108Ozone
2008364235103224004693172Ozone
200736525791170004380143Ozone
200636527670172004280156Ozone
20053652966540004071150Ozone
200436628471110004177143Ozone
200336525590191004390156Ozone
2002365254773040043100172Ozone
200136427074182004284156Ozone
200036427666220004087147Ozone
1999363233106240004587150Ozone
199836527955274004293179Ozone
199736526782151004477164Ozone
1996366251684070043115190Ozone
199536426270302004293192Ozone
199436525687220004290147Ozone
199336525582262004290154Ozone
199236626178252004087159Ozone
199136223594302104697202Ozone
199036524792233004497172Ozone
198936324097251004493187Ozone
1988365230904050044108177Ozone
19873651988558222047140208Ozone
19863533014480003767143Ozone
198535629050124003774164Ozone
198435830045130003561143Ozone
19833623034883003567156Ozone
198236329953110003771122Ozone
198136530049122203771208Ozone
198036430346113103468213Ozone

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