Median AQI
46
Good
Michigan · County air quality · 2025
Kent County, Michigan
Median AQI 46 (Good). 59.9% of monitored days rated Good, direct from EPA Air Quality System stations.
- 46
- Median AQI
- 59.9%
- Good-air days
- 0
- Unhealthy days
- 14%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Kent County's air is good on balance, among the more polluted 10% of US counties, a median AQI of 46 with 59.9% of 304 monitored days in the Good band, driven mainly by Ozone.
- 46
- median AQI · Good
- 59.9%
- days rated Good
- Ozone
- main pollutant
- 14%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 138.
Data updated July 2026
- Good · 182 d · 59.9%
- Moderate · 118 d · 38.8%
- USG · 4 d · 1.3%
How did Kent County's air break down in 2025?
Across 304 monitored days, 182 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 138 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 304 days monitored. Median AQI: 46 (Good).
Insights: Kent County, Michigan. EPA monitors recorded a median Air Quality Index of 46 across 304 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 182 (60%) fell in the Good band (AQI 0–50), 118 (39%) registered Moderate readings, and 4 (1%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 67, while the worst single-day peak hit 138 (USG). Residents averaged about 18.0 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (154 days), PM2.5 (147 days), NO2 (2 days), PM10 (1 days). Across the 2020–2025 trend window, good days shifted by -85 and the median AQI moved +7 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 138, usg but never Unhealthy. Nearby counties show comparable readings: Allegan (71.2% good, AQI 43); Bay (71.8% good, AQI 38); Benzie (91.1% good, AQI 35); Berrien (80.9% good, AQI 41); Cass (85.3% good, AQI 40); Clinton (90.2% good, AQI 39).
Air Quality Summary
Good Days
59.9%
182 of 304 monitored days
-15.1pp vs 75% target
Max AQI Recorded
138
USG
Health Grade
Moderate
90th-pct AQI 67
Kent County, Good days share 59.9%
National avg
Share of monitored days at AQI 0-50 (Good band).
Kent County, Unhealthy-or-worse share 0.0%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 304 monitored days across EPA AQI categories.
Good
182
60%
Moderate
118
39%
USG
4
1%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Kent County.
- Ozone · 154 days · 50.7%
- PM2.5 · 147 days · 48.4%
- NO₂ · 2 days · 0.7%
- PM10 · 1 days · 0.3%
Health Impact Assessment
Moderate
Kent County's air quality is rated Moderate based on 59.9% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 59.9% of monitored days in 2025, with a median AQI of 46. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 154 of 304 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Kent County. Best year: 2020 (267 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 267 | 90 | 7 | 1 | 39 | 154 |
| 2021 | 189 | 173 | 3 | 0 | 49 | 143 |
| 2022 | 209 | 152 | 4 | 0 | 47 | 136 |
| 2023 | 188 | 165 | 9 | 2 | 49 | 220 |
| 2024 | 180 | 185 | 1 | 0 | 51 | 112 |
| 2025 | 182 | 118 | 4 | 0 | 46 | 138 |
How does Kent County compare?
How Kent County compares
Good-day share worse than US avg
Kent County 59.9%
Allegan County, Michigan 71.2%
US average 76.5%
Median AQI worse than US avg
Kent County 46
Allegan County, Michigan 43
US average 38
Unhealthy days / yr about average
Kent County 0
Allegan County, Michigan 1
US average 0
Other Counties in Michigan
Air quality comparison for nearby counties in Michigan.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Kent County.
Bay County, Florida
AQI 46 · 60.6% good
Blount County, Tennessee
AQI 46 · 69.6% good
Cache County, Utah
AQI 46 · 61.2% good
Chesterfield County, South Carolina
AQI 46 · 61.2% good
Clark County, Indiana
AQI 46 · 59.7% good
Clark County, Ohio
AQI 46 · 59.4% good
What Kent County's air means for you
The air here stays in the breathable range year-round, with Ozone the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-Ozone days, the guide explains what a median of 46 means for exposure. Health guidance
- See how Kent County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Kent County with its Michigan neighbours before drawing a conclusion about the region. All of Michigan
Based on 304 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
More Air Quality Data
Air Quality Guides
Frequently Asked Questions
What is the air quality in Kent County, Michigan? ▼
Kent County has a median Air Quality Index (AQI) of 46, rated "Good." 59.9% of monitored days (182 out of 304) had good air quality in 2025.
What is the main pollutant in Kent County? ▼
The primary pollutant in Kent County is Ozone (O3), which was the main AQI driver on 154 days (51% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Kent County have? ▼
In 2025, Kent County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 138.
Is the air quality in Kent County getting better or worse? ▼
Air quality in Kent County is worsening based on 5-year trends (2020-2025). Best year: 2020 with 267 good days. Worst year: 2024 with 180 good days.
What does AQI 46 mean for health? ▼
Kent County's median AQI of 46 falls in the "Good" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Kent County compare to other counties in Michigan? ▼
Kent County has 59.9% good air days. Nearby counties in Michigan: Allegan (71.2% good), Bay (71.8% good), Benzie (91.1% good), Berrien (80.9% good), Cass (85.3% good), Clinton (90.2% good).
What is the 90th percentile AQI in Kent County? ▼
The 90th percentile AQI for Kent County is 67, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 138 (USG).
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer.
Every figure on PlainAir is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.