EnviroNearby

Bucks County, Pennsylvania air quality history

Daily Air Quality Index summaries from EPA monitors in Bucks, Pennsylvania, 1980–2025.

86%
Good days in 2025
36
Median daily AQI, 2025
4
Days above 100 in 2025
362
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Bucks, Pennsylvania on 362 days. 312 of those days (86%) were in the Good range, and the median daily AQI was 36. That median is lower than the typical monitored county in Pennsylvania (median 40 across 38 counties), and lower than the typical monitored U.S. county (40). The main pollutant was ozone on 332 days. Across the years with fuller monitoring, the share of Good days rose: an average of 57% 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 192 of 333 days1980: Moderate 68 of 333 days1980: Unhealthy for Sensitive Groups 27 of 333 days1980: Unhealthy 27 of 333 days1980: Very Unhealthy 19 of 333 days19801981: Good 199 of 350 days1981: Moderate 115 of 350 days1981: Unhealthy for Sensitive Groups 20 of 350 days1981: Unhealthy 11 of 350 days1981: Very Unhealthy 5 of 350 days1982: Good 203 of 360 days1982: Moderate 113 of 360 days1982: Unhealthy for Sensitive Groups 27 of 360 days1982: Unhealthy 14 of 360 days1982: Very Unhealthy 3 of 360 days1983: Good 204 of 363 days1983: Moderate 99 of 363 days1983: Unhealthy for Sensitive Groups 29 of 363 days1983: Unhealthy 16 of 363 days1983: Very Unhealthy 15 of 363 days1984: Good 175 of 365 days1984: Moderate 144 of 365 days1984: Unhealthy for Sensitive Groups 31 of 365 days1984: Unhealthy 8 of 365 days1984: Very Unhealthy 7 of 365 days1985: Good 198 of 362 days1985: Moderate 114 of 362 days1985: Unhealthy for Sensitive Groups 30 of 362 days1985: Unhealthy 16 of 362 days1985: Very Unhealthy 4 of 362 days19851986: Good 202 of 364 days1986: Moderate 109 of 364 days1986: Unhealthy for Sensitive Groups 35 of 364 days1986: Unhealthy 15 of 364 days1986: Very Unhealthy 3 of 364 days1987: Good 203 of 362 days1987: Moderate 105 of 362 days1987: Unhealthy for Sensitive Groups 22 of 362 days1987: Unhealthy 18 of 362 days1987: Very Unhealthy 14 of 362 days1988: Good 218 of 365 days1988: Moderate 87 of 365 days1988: Unhealthy for Sensitive Groups 23 of 365 days1988: Unhealthy 21 of 365 days1988: Very Unhealthy 16 of 365 days1989: Good 238 of 365 days1989: Moderate 88 of 365 days1989: Unhealthy for Sensitive Groups 24 of 365 days1989: Unhealthy 11 of 365 days1989: Very Unhealthy 4 of 365 days1990: Good 249 of 365 days1990: Moderate 84 of 365 days1990: Unhealthy for Sensitive Groups 18 of 365 days1990: Unhealthy 11 of 365 days1990: Very Unhealthy 3 of 365 days19901991: Good 235 of 365 days1991: Moderate 77 of 365 days1991: Unhealthy for Sensitive Groups 28 of 365 days1991: Unhealthy 18 of 365 days1991: Very Unhealthy 7 of 365 days1992: Good 265 of 366 days1992: Moderate 73 of 366 days1992: Unhealthy for Sensitive Groups 19 of 366 days1992: Unhealthy 8 of 366 days1992: Very Unhealthy 1 of 366 days1993: Good 265 of 362 days1993: Moderate 56 of 362 days1993: Unhealthy for Sensitive Groups 29 of 362 days1993: Unhealthy 9 of 362 days1993: Very Unhealthy 3 of 362 days1994: Good 228 of 362 days1994: Moderate 95 of 362 days1994: Unhealthy for Sensitive Groups 26 of 362 days1994: Unhealthy 11 of 362 days1994: Very Unhealthy 2 of 362 days1995: Good 249 of 361 days1995: Moderate 65 of 361 days1995: Unhealthy for Sensitive Groups 25 of 361 days1995: Unhealthy 15 of 361 days1995: Very Unhealthy 7 of 361 days19951996: Good 266 of 365 days1996: Moderate 66 of 365 days1996: Unhealthy for Sensitive Groups 25 of 365 days1996: Unhealthy 7 of 365 days1996: Very Unhealthy 1 of 365 days1997: Good 285 of 365 days1997: Moderate 45 of 365 days1997: Unhealthy for Sensitive Groups 22 of 365 days1997: Unhealthy 11 of 365 days1997: Very Unhealthy 2 of 365 days1998: Good 278 of 365 days1998: Moderate 41 of 365 days1998: Unhealthy for Sensitive Groups 32 of 365 days1998: Unhealthy 14 of 365 days1999: Good 251 of 363 days1999: Moderate 73 of 363 days1999: Unhealthy for Sensitive Groups 19 of 363 days1999: Unhealthy 13 of 363 days1999: Very Unhealthy 7 of 363 days2000: Good 231 of 365 days2000: Moderate 106 of 365 days2000: Unhealthy for Sensitive Groups 15 of 365 days2000: Unhealthy 11 of 365 days2000: Very Unhealthy 2 of 365 days20002001: Good 205 of 365 days2001: Moderate 122 of 365 days2001: Unhealthy for Sensitive Groups 22 of 365 days2001: Unhealthy 14 of 365 days2001: Very Unhealthy 2 of 365 days2002: Good 228 of 365 days2002: Moderate 91 of 365 days2002: Unhealthy for Sensitive Groups 28 of 365 days2002: Unhealthy 11 of 365 days2002: Very Unhealthy 7 of 365 days2003: Good 228 of 365 days2003: Moderate 107 of 365 days2003: Unhealthy for Sensitive Groups 23 of 365 days2003: Unhealthy 5 of 365 days2003: Very Unhealthy 2 of 365 days2004: Good 256 of 366 days2004: Moderate 95 of 366 days2004: Unhealthy for Sensitive Groups 13 of 366 days2004: Unhealthy 2 of 366 days2005: Good 237 of 365 days2005: Moderate 100 of 365 days2005: Unhealthy for Sensitive Groups 21 of 365 days2005: Unhealthy 7 of 365 days20052006: Good 247 of 365 days2006: Moderate 95 of 365 days2006: Unhealthy for Sensitive Groups 16 of 365 days2006: Unhealthy 7 of 365 days2007: Good 249 of 361 days2007: Moderate 80 of 361 days2007: Unhealthy for Sensitive Groups 25 of 361 days2007: Unhealthy 4 of 361 days2007: Very Unhealthy 3 of 361 days2008: Good 250 of 365 days2008: Moderate 93 of 365 days2008: Unhealthy for Sensitive Groups 18 of 365 days2008: Unhealthy 4 of 365 days2009: Good 181 of 365 days2009: Moderate 176 of 365 days2009: Unhealthy for Sensitive Groups 8 of 365 days2010: Good 159 of 365 days2010: Moderate 182 of 365 days2010: Unhealthy for Sensitive Groups 20 of 365 days2010: Unhealthy 4 of 365 days20102011: Good 120 of 365 days2011: Moderate 232 of 365 days2011: Unhealthy for Sensitive Groups 11 of 365 days2011: Unhealthy 2 of 365 days2012: Good 136 of 363 days2012: Moderate 203 of 363 days2012: Unhealthy for Sensitive Groups 23 of 363 days2012: Unhealthy 1 of 363 days2013: Good 163 of 365 days2013: Moderate 188 of 365 days2013: Unhealthy for Sensitive Groups 14 of 365 days2014: Good 146 of 365 days2014: Moderate 211 of 365 days2014: Unhealthy for Sensitive Groups 7 of 365 days2014: Unhealthy 1 of 365 days2015: Good 155 of 362 days2015: Moderate 190 of 362 days2015: Unhealthy for Sensitive Groups 16 of 362 days2015: Unhealthy 1 of 362 days20152016: Good 300 of 349 days2016: Moderate 40 of 349 days2016: Unhealthy for Sensitive Groups 9 of 349 days2017: Good 289 of 335 days2017: Moderate 34 of 335 days2017: Unhealthy for Sensitive Groups 12 of 335 days2018: Good 288 of 333 days2018: Moderate 33 of 333 days2018: Unhealthy for Sensitive Groups 9 of 333 days2018: Unhealthy 3 of 333 days2019: Good 318 of 357 days2019: Moderate 36 of 357 days2019: Unhealthy for Sensitive Groups 3 of 357 days2020: Good 331 of 351 days2020: Moderate 16 of 351 days2020: Unhealthy for Sensitive Groups 4 of 351 days20202021: Good 239 of 283 days2021: Moderate 34 of 283 days2021: Unhealthy for Sensitive Groups 10 of 283 days2022: Good 196 of 237 days2022: Moderate 39 of 237 days2022: Unhealthy for Sensitive Groups 2 of 237 days2023: Good 241 of 296 days2023: Moderate 50 of 296 days2023: Unhealthy for Sensitive Groups 4 of 296 days2023: Unhealthy 1 of 296 days2024: Good 293 of 356 days2024: Moderate 53 of 356 days2024: Unhealthy for Sensitive Groups 10 of 356 days2025: Good 312 of 362 days2025: Moderate 46 of 362 days2025: Unhealthy for Sensitive Groups 4 of 362 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 1721981: 90th percentile AQI 1021982: 90th percentile AQI 1191983: 90th percentile AQI 1401984: 90th percentile AQI 1061985: 90th percentile AQI 1191986: 90th percentile AQI 1191987: 90th percentile AQI 1361988: 90th percentile AQI 1511989: 90th percentile AQI 1011990: 90th percentile AQI 971991: 90th percentile AQI 1261992: 90th percentile AQI 901993: 90th percentile AQI 1081994: 90th percentile AQI 1121995: 90th percentile AQI 1191996: 90th percentile AQI 961997: 90th percentile AQI 971998: 90th percentile AQI 1121999: 90th percentile AQI 1052000: 90th percentile AQI 902001: 90th percentile AQI 1052002: 90th percentile AQI 1122003: 90th percentile AQI 942004: 90th percentile AQI 772005: 90th percentile AQI 932006: 90th percentile AQI 902007: 90th percentile AQI 872008: 90th percentile AQI 822009: 90th percentile AQI 772010: 90th percentile AQI 902011: 90th percentile AQI 862012: 90th percentile AQI 872013: 90th percentile AQI 802014: 90th percentile AQI 762015: 90th percentile AQI 852016: 90th percentile AQI 612017: 90th percentile AQI 612018: 90th percentile AQI 642019: 90th percentile AQI 542020: 90th percentile AQI 462021: 90th percentile AQI 642022: 90th percentile AQI 642023: 90th percentile AQI 712024: 90th percentile AQI 672025: 90th percentile AQI 611980: Median AQI 471981: Median AQI 471982: Median AQI 471983: Median AQI 471984: Median AQI 511985: Median AQI 491986: Median AQI 481987: Median AQI 471988: Median AQI 461989: Median AQI 441990: Median AQI 421991: Median AQI 441992: Median AQI 421993: Median AQI 411994: Median AQI 441995: Median AQI 411996: Median AQI 421997: Median AQI 401998: Median AQI 391999: Median AQI 412000: Median AQI 412001: Median AQI 452002: Median AQI 432003: Median AQI 422004: Median AQI 402005: Median AQI 422006: Median AQI 412007: Median AQI 372008: Median AQI 412009: Median AQI 512010: Median AQI 542011: Median AQI 552012: Median AQI 552013: Median AQI 522014: Median AQI 542015: Median AQI 532016: Median AQI 342017: Median AQI 342018: Median AQI 332019: Median AQI 352020: Median AQI 332021: Median AQI 372022: Median AQI 412023: Median AQI 392024: Median AQI 362025: Median AQI 361980198519901995200020052010201520202025
  • 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
Ozone33292%
Nitrogen dioxide (NO₂)308%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253623124640003661136Ozone
202435629353100003667150Ozone
20232962415041003971200Ozone
20222371963920004164119Ozone
202128323934100003764143Ozone
20203513311640003346115Ozone
20193573183630003554136Ozone
20183332883393003364164Ozone
201733528934120003461143Ozone
20163493004090003461147Ozone
2015362155190161005385164PM2.5
201436514621171005476172PM2.5
2013365163188140005280128PM2.5
2012363136203231005587161PM2.5
2011365120232112005586157PM2.5
2010365159182204005490190PM2.5
200936518117680005177122PM2.5
200836525093184004182192Ozone
200736124980254303787217Ozone
200636524795167004190195Ozone
2005365237100217004293182Ozone
200436625695132004077156Ozone
2003365228107235204294205Ozone
20023652289128117043112220Ozone
200136520512222142045105215Ozone
20003652311061511204190227NO2
19993632517319137041105222NO2
19983652784132140039112187NO2
1997365285452211204097222NO2
199636526666257104296214NO2
19953612496525157041119219NO2
19943622289526112044112210NO2
1993362265562993041108213NO2
199236626573198104290204NO2
19913652357728187044126212Ozone
1990365249841811304297214NO2
19893652388824114044101209NO2
198836521887232116046151260NO2
1987362203105221814047136228NO2
198636420210935153048119228NO2
198536219811430164049119219NO2
19843651751443187051106258NO2
198336320499291615047140230NO2
198236020311327143047119217NO2
198135019911520115047102219NO2
198033319268272719047172268NO2

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 Pennsylvania with a similar median AQI in 2025

All monitored counties in Pennsylvania

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