EnviroNearby

Davis County, Utah air quality history

Daily Air Quality Index summaries from EPA monitors in Davis, Utah, 1980–2025.

63%
Good days in 2025
46
Median daily AQI, 2025
7
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 Davis, Utah on 365 days. 231 of those days (63%) were in the Good range, and the median daily AQI was 46. That median is about the same as the typical monitored county in Utah (median 45 across 15 counties), and higher than the typical monitored U.S. county (40). The main pollutant was ozone on 269 days. Across the years with fuller monitoring, the share of Good days held roughly steady: an average of 60% in 1980–1982 versus 62% 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 221 of 366 days1980: Moderate 110 of 366 days1980: Unhealthy for Sensitive Groups 32 of 366 days1980: Unhealthy 2 of 366 days1980: Very Unhealthy 1 of 366 days19801981: Good 218 of 362 days1981: Moderate 100 of 362 days1981: Unhealthy for Sensitive Groups 34 of 362 days1981: Unhealthy 9 of 362 days1981: Very Unhealthy 1 of 362 days1982: Good 222 of 365 days1982: Moderate 102 of 365 days1982: Unhealthy for Sensitive Groups 32 of 365 days1982: Unhealthy 8 of 365 days1982: Very Unhealthy 1 of 365 days1983: Good 281 of 348 days1983: Moderate 46 of 348 days1983: Unhealthy for Sensitive Groups 18 of 348 days1983: Unhealthy 3 of 348 days1984: Good 250 of 364 days1984: Moderate 81 of 364 days1984: Unhealthy for Sensitive Groups 24 of 364 days1984: Unhealthy 7 of 364 days1984: Very Unhealthy 2 of 364 days1985: Good 256 of 350 days1985: Moderate 65 of 350 days1985: Unhealthy for Sensitive Groups 19 of 350 days1985: Unhealthy 10 of 350 days19851986: Good 252 of 360 days1986: Moderate 74 of 360 days1986: Unhealthy for Sensitive Groups 26 of 360 days1986: Unhealthy 7 of 360 days1986: Very Unhealthy 1 of 360 days1987: Good 241 of 362 days1987: Moderate 95 of 362 days1987: Unhealthy for Sensitive Groups 22 of 362 days1987: Unhealthy 4 of 362 days1988: Good 256 of 356 days1988: Moderate 69 of 356 days1988: Unhealthy for Sensitive Groups 24 of 356 days1988: Unhealthy 7 of 356 days1989: Good 206 of 336 days1989: Moderate 103 of 336 days1989: Unhealthy for Sensitive Groups 16 of 336 days1989: Unhealthy 9 of 336 days1989: Very Unhealthy 2 of 336 days1990: Good 240 of 359 days1990: Moderate 97 of 359 days1990: Unhealthy for Sensitive Groups 19 of 359 days1990: Unhealthy 3 of 359 days19901991: Good 241 of 332 days1991: Moderate 74 of 332 days1991: Unhealthy for Sensitive Groups 17 of 332 days1992: Good 247 of 366 days1992: Moderate 106 of 366 days1992: Unhealthy for Sensitive Groups 13 of 366 days1993: Good 247 of 358 days1993: Moderate 100 of 358 days1993: Unhealthy for Sensitive Groups 11 of 358 days1994: Good 243 of 361 days1994: Moderate 107 of 361 days1994: Unhealthy for Sensitive Groups 11 of 361 days1995: Good 258 of 350 days1995: Moderate 80 of 350 days1995: Unhealthy for Sensitive Groups 9 of 350 days1995: Unhealthy 3 of 350 days19951996: Good 226 of 347 days1996: Moderate 88 of 347 days1996: Unhealthy for Sensitive Groups 29 of 347 days1996: Unhealthy 4 of 347 days1997: Good 242 of 361 days1997: Moderate 106 of 361 days1997: Unhealthy for Sensitive Groups 13 of 361 days1998: Good 239 of 363 days1998: Moderate 102 of 363 days1998: Unhealthy for Sensitive Groups 14 of 363 days1998: Unhealthy 8 of 363 days1999: Good 231 of 362 days1999: Moderate 118 of 362 days1999: Unhealthy for Sensitive Groups 11 of 362 days1999: Unhealthy 2 of 362 days2000: Good 218 of 359 days2000: Moderate 114 of 359 days2000: Unhealthy for Sensitive Groups 21 of 359 days2000: Unhealthy 4 of 359 days2000: Very Unhealthy 2 of 359 days20002001: Good 219 of 365 days2001: Moderate 124 of 365 days2001: Unhealthy for Sensitive Groups 19 of 365 days2001: Unhealthy 2 of 365 days2001: Very Unhealthy 1 of 365 days2002: Good 220 of 364 days2002: Moderate 113 of 364 days2002: Unhealthy for Sensitive Groups 24 of 364 days2002: Unhealthy 7 of 364 days2003: Good 217 of 334 days2003: Moderate 100 of 334 days2003: Unhealthy for Sensitive Groups 17 of 334 days2004: Good 229 of 364 days2004: Moderate 126 of 364 days2004: Unhealthy for Sensitive Groups 7 of 364 days2004: Unhealthy 2 of 364 days2005: Good 233 of 360 days2005: Moderate 96 of 360 days2005: Unhealthy for Sensitive Groups 23 of 360 days2005: Unhealthy 7 of 360 days2005: Very Unhealthy 1 of 360 days20052006: Good 235 of 363 days2006: Moderate 112 of 363 days2006: Unhealthy for Sensitive Groups 15 of 363 days2006: Unhealthy 1 of 363 days2007: Good 210 of 363 days2007: Moderate 134 of 363 days2007: Unhealthy for Sensitive Groups 14 of 363 days2007: Unhealthy 5 of 363 days2008: Good 217 of 361 days2008: Moderate 127 of 361 days2008: Unhealthy for Sensitive Groups 17 of 361 days2009: Good 265 of 359 days2009: Moderate 82 of 359 days2009: Unhealthy for Sensitive Groups 11 of 359 days2009: Unhealthy 1 of 359 days2010: Good 287 of 365 days2010: Moderate 68 of 365 days2010: Unhealthy for Sensitive Groups 9 of 365 days2010: Unhealthy 1 of 365 days20102011: Good 294 of 363 days2011: Moderate 65 of 363 days2011: Unhealthy for Sensitive Groups 3 of 363 days2011: Unhealthy 1 of 363 days2012: Good 288 of 366 days2012: Moderate 78 of 366 days2013: Good 281 of 360 days2013: Moderate 68 of 360 days2013: Unhealthy for Sensitive Groups 11 of 360 days2014: Good 265 of 365 days2014: Moderate 89 of 365 days2014: Unhealthy for Sensitive Groups 11 of 365 days2015: Good 270 of 357 days2015: Moderate 80 of 357 days2015: Unhealthy for Sensitive Groups 7 of 357 days20152016: Good 224 of 366 days2016: Moderate 128 of 366 days2016: Unhealthy for Sensitive Groups 14 of 366 days2017: Good 180 of 365 days2017: Moderate 157 of 365 days2017: Unhealthy for Sensitive Groups 28 of 365 days2018: Good 194 of 365 days2018: Moderate 158 of 365 days2018: Unhealthy for Sensitive Groups 12 of 365 days2018: Unhealthy 1 of 365 days2019: Good 239 of 365 days2019: Moderate 120 of 365 days2019: Unhealthy for Sensitive Groups 6 of 365 days2020: Good 217 of 366 days2020: Moderate 135 of 366 days2020: Unhealthy for Sensitive Groups 13 of 366 days2020: Unhealthy 1 of 366 days20202021: Good 205 of 365 days2021: Moderate 134 of 365 days2021: Unhealthy for Sensitive Groups 25 of 365 days2021: Unhealthy 1 of 365 days2022: Good 210 of 365 days2022: Moderate 145 of 365 days2022: Unhealthy for Sensitive Groups 10 of 365 days2023: Good 211 of 365 days2023: Moderate 141 of 365 days2023: Unhealthy for Sensitive Groups 12 of 365 days2023: Unhealthy 1 of 365 days2024: Good 234 of 366 days2024: Moderate 117 of 366 days2024: Unhealthy for Sensitive Groups 15 of 366 days2025: Good 231 of 365 days2025: Moderate 127 of 365 days2025: Unhealthy for Sensitive Groups 7 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 1001981: 90th percentile AQI 1051982: 90th percentile AQI 1031983: 90th percentile AQI 871984: 90th percentile AQI 971985: 90th percentile AQI 931986: 90th percentile AQI 971987: 90th percentile AQI 931988: 90th percentile AQI 971989: 90th percentile AQI 931990: 90th percentile AQI 871991: 90th percentile AQI 801992: 90th percentile AQI 771993: 90th percentile AQI 731994: 90th percentile AQI 781995: 90th percentile AQI 711996: 90th percentile AQI 1001997: 90th percentile AQI 731998: 90th percentile AQI 811999: 90th percentile AQI 742000: 90th percentile AQI 972001: 90th percentile AQI 932002: 90th percentile AQI 932003: 90th percentile AQI 842004: 90th percentile AQI 772005: 90th percentile AQI 962006: 90th percentile AQI 872007: 90th percentile AQI 902008: 90th percentile AQI 802009: 90th percentile AQI 742010: 90th percentile AQI 712011: 90th percentile AQI 642012: 90th percentile AQI 642013: 90th percentile AQI 592014: 90th percentile AQI 672015: 90th percentile AQI 672016: 90th percentile AQI 742017: 90th percentile AQI 972018: 90th percentile AQI 872019: 90th percentile AQI 742020: 90th percentile AQI 782021: 90th percentile AQI 922022: 90th percentile AQI 842023: 90th percentile AQI 842024: 90th percentile AQI 842025: 90th percentile AQI 781980: Median AQI 471981: Median AQI 471982: Median AQI 471983: Median AQI 381984: Median AQI 441985: Median AQI 421986: Median AQI 431987: Median AQI 441988: Median AQI 421989: Median AQI 461990: Median AQI 451991: Median AQI 431992: Median AQI 441993: Median AQI 441994: Median AQI 451995: Median AQI 431996: Median AQI 451997: Median AQI 451998: Median AQI 441999: Median AQI 462000: Median AQI 442001: Median AQI 462002: Median AQI 462003: Median AQI 442004: Median AQI 462005: Median AQI 442006: Median AQI 452007: Median AQI 472008: Median AQI 462009: Median AQI 442010: Median AQI 402011: Median AQI 402012: Median AQI 412013: Median AQI 422014: Median AQI 442015: Median AQI 392016: Median AQI 472017: Median AQI 512018: Median AQI 492019: Median AQI 452020: Median AQI 462021: Median AQI 472022: Median AQI 472023: Median AQI 472024: Median AQI 462025: Median AQI 461980198519901995200020052010201520202025
  • 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
Ozone26974%
Fine particles (PM2.5)6016%
Nitrogen dioxide (NO₂)329%
Coarse particles (PM10)41%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
202536523112770004678119Ozone
2024366234117150004684133Ozone
2023365211141121004784151Ozone
2022365210145100004784147Ozone
2021365205134251004792156Ozone
2020366217135131004678157Ozone
201936523912060004574119Ozone
2018365194158121004987151Ozone
2017365180157280005197140Ozone
2016366224128140004774143Ozone
20153572708070003967143Ozone
201436526589110004467130Ozone
201336028168110004259140Ozone
20123662887800004164100Ozone
20113632946531004064152Ozone
20103652876891004071152NO2
200935926582111004474151Ozone
2008361217127170004680147NO2
2007363210134145004790160NO2
2006363235112151004587174NO2
200536023396237104496203NO2
200436422912672004677164NO2
2003334217100170004484143NO2
2002364220113247004693169NO2
2001365219124192104693204NO2
2000359218114214204497214NO2
1999362231118112004674185NO2
1998363239102148004481195NO2
1997361242106130004573143NO2
1996347226882940045100164NO2
19953502588093004371185NO2
1994361243107110004578143NO2
1993358247100110004473147NO2
1992366247106130004477119Ozone
199133224174170004380150Ozone
199035924097193004587161Ozone
1989336206103169204693227Ozone
198835625669247004297187Ozone
198736224195224004493172Ozone
198636025274267104397219Ozone
1985350256651910004293187Ozone
198436425081247204497214Ozone
198334828146183003887164Ozone
19823652221023281047103212Ozone
19813622181003491047105201Ozone
19803662211103221047100224NO2

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 Utah with a similar median AQI in 2025

All monitored counties in Utah

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