EnviroNearby

Androscoggin County, Maine air quality history

Daily Air Quality Index summaries from EPA monitors in Androscoggin, Maine, 1980–2025.

85%
Good days in 2025
34
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 Androscoggin, Maine on 365 days. 311 of those days (85%) were in the Good range, and the median daily AQI was 34. That median is about the same as the typical monitored county in Maine (median 34 across 11 counties), and lower than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 185 days. Across the years with fuller monitoring, the share of Good days rose: an average of 84% in 1980–2004 versus 87% in 2023–2025.

Years with fewer than 120 monitored days (1998, 1999, 2000, 2001, 2002, 2003…) are shown in the table but left out of comparisons and trend statements.

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 271 of 295 days1980: Moderate 24 of 295 days19801988: Good 98 of 139 days1988: Moderate 23 of 139 days1988: Unhealthy for Sensitive Groups 13 of 139 days1988: Unhealthy 4 of 139 days1988: Very Unhealthy 1 of 139 days1990: Good 59 of 61 days1990: Moderate 2 of 61 days1991: Good 51 of 56 days1991: Moderate 5 of 56 days1992: Good 56 of 59 days1992: Moderate 3 of 59 days1993: Good 57 of 60 days1993: Moderate 3 of 60 days19931994: Good 57 of 58 days1994: Moderate 1 of 58 days1995: Good 59 of 60 days1995: Moderate 1 of 60 days1996: Good 62 of 62 days1997: Good 59 of 59 days1998: Good 53 of 54 days1998: Moderate 1 of 54 days19981999: Good 51 of 51 days2000: Good 51 of 51 days2001: Good 59 of 59 days2002: Good 49 of 51 days2002: Moderate 2 of 51 days2003: Good 54 of 56 days2003: Moderate 2 of 56 days20032004: Good 162 of 182 days2004: Moderate 16 of 182 days2004: Unhealthy for Sensitive Groups 4 of 182 days2005: Good 153 of 171 days2005: Moderate 16 of 171 days2005: Unhealthy for Sensitive Groups 2 of 171 days2006: Good 120 of 132 days2006: Moderate 10 of 132 days2006: Unhealthy for Sensitive Groups 2 of 132 days2007: Good 185 of 211 days2007: Moderate 16 of 211 days2007: Unhealthy for Sensitive Groups 7 of 211 days2007: Unhealthy 3 of 211 days2008: Good 188 of 209 days2008: Moderate 18 of 209 days2008: Unhealthy for Sensitive Groups 3 of 209 days20082009: Good 206 of 212 days2009: Moderate 6 of 212 days2010: Good 267 of 365 days2010: Moderate 96 of 365 days2010: Unhealthy for Sensitive Groups 1 of 365 days2010: Unhealthy 1 of 365 days2011: Good 234 of 365 days2011: Moderate 131 of 365 days2012: Good 263 of 363 days2012: Moderate 100 of 363 days2013: Good 271 of 361 days2013: Moderate 90 of 361 days20132014: Good 245 of 347 days2014: Moderate 102 of 347 days2015: Good 236 of 358 days2015: Moderate 122 of 358 days2016: Good 297 of 358 days2016: Moderate 61 of 358 days2017: Good 233 of 359 days2017: Moderate 126 of 359 days2018: Good 309 of 361 days2018: Moderate 52 of 361 days20182019: Good 327 of 361 days2019: Moderate 34 of 361 days2020: Good 327 of 360 days2020: Moderate 33 of 360 days2021: Good 303 of 356 days2021: Moderate 53 of 356 days2022: Good 327 of 358 days2022: Moderate 31 of 358 days2023: Good 296 of 359 days2023: Moderate 63 of 359 days20232024: Good 339 of 366 days2024: Moderate 27 of 366 days2025: Good 311 of 365 days2025: Moderate 52 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 year0501001501980: 90th percentile AQI 451988: 90th percentile AQI 1081990: 90th percentile AQI 381991: 90th percentile AQI 461992: 90th percentile AQI 401993: 90th percentile AQI 461994: 90th percentile AQI 321995: 90th percentile AQI 341996: 90th percentile AQI 291997: 90th percentile AQI 321998: 90th percentile AQI 291999: 90th percentile AQI 292000: 90th percentile AQI 262001: 90th percentile AQI 342002: 90th percentile AQI 342003: 90th percentile AQI 382004: 90th percentile AQI 512005: 90th percentile AQI 512006: 90th percentile AQI 482007: 90th percentile AQI 582008: 90th percentile AQI 512009: 90th percentile AQI 462010: 90th percentile AQI 592011: 90th percentile AQI 642012: 90th percentile AQI 582013: 90th percentile AQI 592014: 90th percentile AQI 612015: 90th percentile AQI 612016: 90th percentile AQI 542017: 90th percentile AQI 602018: 90th percentile AQI 542019: 90th percentile AQI 492020: 90th percentile AQI 492021: 90th percentile AQI 532022: 90th percentile AQI 482023: 90th percentile AQI 552024: 90th percentile AQI 472025: 90th percentile AQI 541980: Median AQI 241988: Median AQI 391990: Median AQI 221991: Median AQI 231992: Median AQI 191993: Median AQI 191994: Median AQI 181995: Median AQI 171996: Median AQI 181997: Median AQI 161998: Median AQI 161999: Median AQI 152000: Median AQI 142001: Median AQI 172002: Median AQI 122003: Median AQI 182004: Median AQI 312005: Median AQI 292006: Median AQI 242007: Median AQI 322008: Median AQI 352009: Median AQI 312010: Median AQI 392011: Median AQI 412012: Median AQI 392013: Median AQI 382014: Median AQI 422015: Median AQI 432016: Median AQI 352017: Median AQI 442018: Median AQI 342019: Median AQI 332020: Median AQI 342021: Median AQI 362022: Median AQI 322023: Median AQI 352024: Median AQI 312025: Median AQI 34198019931998200320082013201820232025
  • 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
Fine particles (PM2.5)18551%
Ozone17548%
Coarse particles (PM10)51%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253653115220003454112PM2.5
2024366339270000314777PM2.5
2023359296630000355577PM2.5
2022358327310000324897Ozone
2021356303530000365395PM2.5
2020360327330000344970PM2.5
2019361327340000334976PM2.5
2018361309520000345484PM2.5
201735923312600004460100PM2.5
2016358297610000355482PM2.5
20153582361220000436197PM2.5
20143472451020000426190PM2.5
2013361271900000385995PM2.5
20123632631000000395897PM2.5
20113652341310000416493PM2.5
20103652679611003959161PM2.5
200921220660000314693Ozone
20082091881830003551129Ozone
20072111851673003258166Ozone
20061321201020002448129Ozone
20051711531620002951150Ozone
20041821621640003151143Ozone
2003565420000183857PM10
2002514920000123463PM10
2001595900000173449PM10
2000515100000142644PM10
1999515100000152944PM10
1998545310000162954PM10
1997595900000163250PM10
1996626200000182948PM10
1995605910000173452PM10
1994585710000183251PM10
1993605730000194658PM10
1992595630000194064PM10
1991565150000234656PM10
1990615920000223853PM10
198813998231341039108216Ozone
1980295271240000244597CO

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 Maine with a similar median AQI in 2025

All monitored counties in Maine

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