EnviroNearby

Muskegon County, Michigan air quality history

Daily Air Quality Index summaries from EPA monitors in Muskegon, Michigan, 1980–2025.

84%
Good days in 2025
39
Median daily AQI, 2025
2
Days above 100 in 2025
243
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Muskegon, Michigan on 243 days. 203 of those days (84%) were in the Good range, and the median daily AQI was 39. That median is about the same as the typical monitored county in Michigan (median 39 across 26 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was ozone on 243 days. Across the years with fuller monitoring, the share of Good days held roughly steady: an average of 81% in 1980–1982 versus 81% in 2023–2025.

EPA did not report an AQI for every day of 2025 here (243 of 365 days). Figures describe monitored days only; seasonal monitoring (for example, ozone measured only in warmer months) can make a county look cleaner or dirtier than a full-year record would.

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 293 of 366 days1980: Moderate 44 of 366 days1980: Unhealthy for Sensitive Groups 15 of 366 days1980: Unhealthy 10 of 366 days1980: Very Unhealthy 4 of 366 days19801981: Good 188 of 241 days1981: Moderate 35 of 241 days1981: Unhealthy for Sensitive Groups 11 of 241 days1981: Unhealthy 6 of 241 days1981: Very Unhealthy 1 of 241 days1982: Good 298 of 352 days1982: Moderate 26 of 352 days1982: Unhealthy for Sensitive Groups 23 of 352 days1982: Unhealthy 4 of 352 days1982: Very Unhealthy 1 of 352 days1983: Good 286 of 352 days1983: Moderate 26 of 352 days1983: Unhealthy for Sensitive Groups 24 of 352 days1983: Unhealthy 10 of 352 days1983: Very Unhealthy 6 of 352 days1984: Good 294 of 335 days1984: Moderate 23 of 335 days1984: Unhealthy for Sensitive Groups 13 of 335 days1984: Unhealthy 5 of 335 days1985: Good 278 of 350 days1985: Moderate 44 of 350 days1985: Unhealthy for Sensitive Groups 18 of 350 days1985: Unhealthy 7 of 350 days1985: Very Unhealthy 3 of 350 days19851986: Good 288 of 352 days1986: Moderate 37 of 352 days1986: Unhealthy for Sensitive Groups 16 of 352 days1986: Unhealthy 8 of 352 days1986: Very Unhealthy 3 of 352 days1987: Good 293 of 363 days1987: Moderate 27 of 363 days1987: Unhealthy for Sensitive Groups 18 of 363 days1987: Unhealthy 17 of 363 days1987: Very Unhealthy 8 of 363 days1988: Good 203 of 276 days1988: Moderate 32 of 276 days1988: Unhealthy for Sensitive Groups 16 of 276 days1988: Unhealthy 14 of 276 days1988: Very Unhealthy 11 of 276 days1989: Good 137 of 222 days1989: Moderate 51 of 222 days1989: Unhealthy for Sensitive Groups 18 of 222 days1989: Unhealthy 12 of 222 days1989: Very Unhealthy 4 of 222 days1990: Good 137 of 204 days1990: Moderate 36 of 204 days1990: Unhealthy for Sensitive Groups 17 of 204 days1990: Unhealthy 12 of 204 days1990: Very Unhealthy 2 of 204 days19901991: Good 136 of 213 days1991: Moderate 32 of 213 days1991: Unhealthy for Sensitive Groups 23 of 213 days1991: Unhealthy 16 of 213 days1991: Very Unhealthy 6 of 213 days1992: Good 132 of 182 days1992: Moderate 34 of 182 days1992: Unhealthy for Sensitive Groups 12 of 182 days1992: Unhealthy 3 of 182 days1992: Very Unhealthy 1 of 182 days1993: Good 137 of 182 days1993: Moderate 28 of 182 days1993: Unhealthy for Sensitive Groups 14 of 182 days1993: Unhealthy 2 of 182 days1993: Very Unhealthy 1 of 182 days1994: Good 115 of 183 days1994: Moderate 42 of 183 days1994: Unhealthy for Sensitive Groups 15 of 183 days1994: Unhealthy 11 of 183 days1995: Good 118 of 183 days1995: Moderate 35 of 183 days1995: Unhealthy for Sensitive Groups 17 of 183 days1995: Unhealthy 9 of 183 days1995: Very Unhealthy 4 of 183 days19951996: Good 133 of 181 days1996: Moderate 30 of 181 days1996: Unhealthy for Sensitive Groups 13 of 181 days1996: Unhealthy 4 of 181 days1996: Very Unhealthy 1 of 181 days1997: Good 139 of 182 days1997: Moderate 32 of 182 days1997: Unhealthy for Sensitive Groups 9 of 182 days1997: Unhealthy 2 of 182 days1998: Good 103 of 177 days1998: Moderate 46 of 177 days1998: Unhealthy for Sensitive Groups 18 of 177 days1998: Unhealthy 10 of 177 days1999: Good 140 of 277 days1999: Moderate 96 of 277 days1999: Unhealthy for Sensitive Groups 21 of 277 days1999: Unhealthy 18 of 277 days1999: Very Unhealthy 2 of 277 days2000: Good 155 of 243 days2000: Moderate 72 of 243 days2000: Unhealthy for Sensitive Groups 14 of 243 days2000: Unhealthy 1 of 243 days2000: Very Unhealthy 1 of 243 days20002001: Good 139 of 243 days2001: Moderate 78 of 243 days2001: Unhealthy for Sensitive Groups 17 of 243 days2001: Unhealthy 9 of 243 days2002: Good 125 of 240 days2002: Moderate 88 of 240 days2002: Unhealthy for Sensitive Groups 20 of 240 days2002: Unhealthy 5 of 240 days2002: Very Unhealthy 2 of 240 days2003: Good 137 of 243 days2003: Moderate 87 of 243 days2003: Unhealthy for Sensitive Groups 14 of 243 days2003: Unhealthy 3 of 243 days2003: Very Unhealthy 2 of 243 days2004: Good 166 of 243 days2004: Moderate 73 of 243 days2004: Unhealthy for Sensitive Groups 4 of 243 days2005: Good 133 of 239 days2005: Moderate 76 of 239 days2005: Unhealthy for Sensitive Groups 20 of 239 days2005: Unhealthy 9 of 239 days2005: Very Unhealthy 1 of 239 days20052006: Good 140 of 223 days2006: Moderate 70 of 223 days2006: Unhealthy for Sensitive Groups 8 of 223 days2006: Unhealthy 5 of 223 days2007: Good 180 of 356 days2007: Moderate 154 of 356 days2007: Unhealthy for Sensitive Groups 18 of 356 days2007: Unhealthy 4 of 356 days2008: Good 201 of 356 days2008: Moderate 150 of 356 days2008: Unhealthy for Sensitive Groups 4 of 356 days2008: Unhealthy 1 of 356 days2009: Good 194 of 297 days2009: Moderate 98 of 297 days2009: Unhealthy for Sensitive Groups 4 of 297 days2009: Unhealthy 1 of 297 days2010: Good 163 of 243 days2010: Moderate 72 of 243 days2010: Unhealthy for Sensitive Groups 8 of 243 days20102011: Good 171 of 241 days2011: Moderate 62 of 241 days2011: Unhealthy for Sensitive Groups 5 of 241 days2011: Unhealthy 3 of 241 days2012: Good 149 of 242 days2012: Moderate 58 of 242 days2012: Unhealthy for Sensitive Groups 26 of 242 days2012: Unhealthy 9 of 242 days2013: Good 137 of 210 days2013: Moderate 67 of 210 days2013: Unhealthy for Sensitive Groups 6 of 210 days2014: Good 147 of 183 days2014: Moderate 30 of 183 days2014: Unhealthy for Sensitive Groups 6 of 183 days2015: Good 139 of 176 days2015: Moderate 31 of 176 days2015: Unhealthy for Sensitive Groups 5 of 176 days2015: Unhealthy 1 of 176 days20152016: Good 138 of 178 days2016: Moderate 33 of 178 days2016: Unhealthy for Sensitive Groups 5 of 178 days2016: Unhealthy 2 of 178 days2017: Good 202 of 245 days2017: Moderate 38 of 245 days2017: Unhealthy for Sensitive Groups 5 of 245 days2018: Good 203 of 240 days2018: Moderate 31 of 240 days2018: Unhealthy for Sensitive Groups 3 of 240 days2018: Unhealthy 3 of 240 days2019: Good 236 of 262 days2019: Moderate 25 of 262 days2019: Unhealthy for Sensitive Groups 1 of 262 days2020: Good 210 of 248 days2020: Moderate 32 of 248 days2020: Unhealthy for Sensitive Groups 6 of 248 days20202021: Good 209 of 265 days2021: Moderate 48 of 265 days2021: Unhealthy for Sensitive Groups 8 of 265 days2022: Good 211 of 243 days2022: Moderate 25 of 243 days2022: Unhealthy for Sensitive Groups 5 of 243 days2022: Unhealthy 2 of 243 days2023: Good 187 of 242 days2023: Moderate 44 of 242 days2023: Unhealthy for Sensitive Groups 11 of 242 days2024: Good 203 of 243 days2024: Moderate 36 of 243 days2024: Unhealthy for Sensitive Groups 4 of 243 days2025: Good 203 of 243 days2025: Moderate 38 of 243 days2025: Unhealthy for Sensitive Groups 2 of 243 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 801981: 90th percentile AQI 871982: 90th percentile AQI 901983: 90th percentile AQI 1051984: 90th percentile AQI 601985: 90th percentile AQI 901986: 90th percentile AQI 901987: 90th percentile AQI 1151988: 90th percentile AQI 1431989: 90th percentile AQI 1221990: 90th percentile AQI 1261991: 90th percentile AQI 1541992: 90th percentile AQI 971993: 90th percentile AQI 871994: 90th percentile AQI 1221995: 90th percentile AQI 1261996: 90th percentile AQI 1001997: 90th percentile AQI 841998: 90th percentile AQI 1291999: 90th percentile AQI 1332000: 90th percentile AQI 842001: 90th percentile AQI 1052002: 90th percentile AQI 1082003: 90th percentile AQI 972004: 90th percentile AQI 712005: 90th percentile AQI 1082006: 90th percentile AQI 872007: 90th percentile AQI 822008: 90th percentile AQI 742009: 90th percentile AQI 712010: 90th percentile AQI 772011: 90th percentile AQI 672012: 90th percentile AQI 1152013: 90th percentile AQI 742014: 90th percentile AQI 742015: 90th percentile AQI 712016: 90th percentile AQI 712017: 90th percentile AQI 672018: 90th percentile AQI 672019: 90th percentile AQI 502020: 90th percentile AQI 642021: 90th percentile AQI 712022: 90th percentile AQI 582023: 90th percentile AQI 872024: 90th percentile AQI 582025: 90th percentile AQI 611980: Median AQI 341981: Median AQI 291982: Median AQI 281983: Median AQI 261984: Median AQI 271985: Median AQI 311986: Median AQI 251987: Median AQI 231988: Median AQI 351989: Median AQI 441990: Median AQI 431991: Median AQI 431992: Median AQI 411993: Median AQI 411994: Median AQI 441995: Median AQI 441996: Median AQI 421997: Median AQI 421998: Median AQI 461999: Median AQI 502000: Median AQI 432001: Median AQI 472002: Median AQI 482003: Median AQI 472004: Median AQI 382005: Median AQI 482006: Median AQI 442007: Median AQI 502008: Median AQI 452009: Median AQI 432010: Median AQI 432011: Median AQI 422012: Median AQI 452013: Median AQI 442014: Median AQI 412015: Median AQI 422016: Median AQI 412017: Median AQI 392018: Median AQI 402019: Median AQI 382020: Median AQI 372021: Median AQI 402022: Median AQI 372023: Median AQI 412024: Median AQI 382025: 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
Ozone243100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20252432033820003961140Ozone
20242432033640003858122Ozone
202324218744110004187147Ozone
20222432112552003758187Ozone
20212652094880004071129Ozone
20202482103260003764143Ozone
20192622362510003850133Ozone
20182402033133004067174Ozone
20172452023850003967140Ozone
20161781383352004171159Ozone
20151761393151004271159Ozone
20141831473060004174129Ozone
20132101376760004474126Ozone
2012242149582690045115195Ozone
20112411716253004267197Ozone
20102431637280004377129Ozone
20092971949841004371156Ozone
200835620115041004574185PM2.5
2007356180154184005082169PM2.5
20062231407085004487192Ozone
2005239133762091048108208Ozone
20042431667340003871129Ozone
200324313787143204797203Ozone
2002240125882052048108205Ozone
2001243139781790047105190Ozone
200024315572141104384206Ozone
19992771409621182050133221Ozone
19981771034618100046129187Ozone
19971821393292004284187Ozone
1996181133301341042100225Ozone
1995183118351794044126251Ozone
19941831154215110044122200Ozone
199318213728142104187204Ozone
199218213234123104197207Ozone
19912131363223166043154224Ozone
19902041373617122043126209Ozone
19892221375118124044122236Ozone
198827620332161411035143255Ozone
19873632932718178023115232CO
198635228837168302590216Ozone
198535027844187303190215Ozone
198433529423135002760182CO
19833522862624106026105225Ozone
198235229826234102890214Ozone
198124118835116102987219Ozone
1980366293441510403480215Ozone

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 Michigan with a similar median AQI in 2025

All monitored counties in Michigan

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