Is the Air Quality Good in Allegan, Michigan?
Yes — air quality in Allegan, Michigan is good. The city earns an Air Quality Grade of B (good) on a 5-year median AQI of 40, which sits in the Good range, and logs only 37 unhealthy-air days over five years (about 7 per year). The general population can breathe outdoors safely on the vast majority of days.
Who Can Safely Breathe the Air in Allegan, Michigan?
For most healthy adults, current air quality in this area does not require any change in behavior. People with severe asthma, COPD, or recent cardiac events should still keep an eye on daily AQI alerts, especially during wildfire season. Because ozone peaks in the afternoon on hot sunny days, plan outdoor exercise for early morning or after sunset on bad-air days.
Across the past five years, this area has logged 37 days where AQI rose into the "Unhealthy for Sensitive Groups" range or worse — about 7 days per year. That is roughly typical for a U.S. metro, with most caution days clustered in summer (ozone) or wildfire season.
Allegan, Michigan Air Quality Snapshot
| Air Quality Grade | B65/100 |
| 5-Year Median AQI | 40 (Good) |
| Most Recent Median AQI (2023) | 42 (Good) |
| Dominant Pollutant | Ground-Level Ozone |
| 10-Year Trend | Improving (-0.30 AQI/yr) |
| Unhealthy Days (last 5 yr) | 37 |
| National Rank (cleanest = #1) | #479 of 1,020 (47th cleanest percentile) |
| Michigan Rank | #16 of 28 |
What Does the B Grade Mean?
Allegan, Michigan earns a B — air quality is reliably in the safe range for most residents most of the time, with a 5-year median AQI of 40. Sensitive groups will see occasional caution days, but the typical resident will not need to change behavior based on air quality.
Allegan, Michigan's 5-year median AQI of 40 is right around the national average of 41 across the 1,020 monitored U.S. cities tracked here. Within Michigan, Allegan, Michigan's air quality is roughly typical for the state, where the average city posts a 5-year median AQI of 39.
For context within Michigan: Monroe, Michigan currently holds the state's cleanest grade (A, AQI 21), while Wayne, Michigan sits at the bottom (C, AQI 58).
What's in Allegan, Michigan's Air?
The dominant pollutant in Allegan, Michigan is Ground-Level Ozone. Ground-level ozone forms when sunlight reacts with vehicle exhaust and industrial emissions. It is worst on hot, sunny, stagnant summer days. Ozone irritates the lungs, triggers asthma attacks, and reduces lung function — even healthy adults can feel chest tightness and shortness of breath after exercising in elevated ozone.
Days by Dominant Pollutant (2023)
| Pollutant | Days as Dominant | Share of Year |
|---|---|---|
| Ground-Level Ozone | 200 | 56% |
| Fine Particulate Matter (PM2.5) | 160 | 44% |
Is the Air Getting Better or Worse?
Air quality in Allegan, Michigan has been improving over the past decade, with median AQI dropping by roughly 0.3 points per year. That is consistent with the broader national pattern — most U.S. metros have seen steady reductions in particulate and ozone pollution since the 2010s as cleaner vehicles and power plants come online.
In 2014, Allegan, Michigan posted a median AQI of 44. By 2023 that figure was 42 — a drop of 2 AQI points cleaner across 10 years of EPA records.
Year-by-Year AQI in Allegan, Michigan
| Year | Median AQI | Good Days | Unhealthy Days | Dominant Pollutant |
|---|---|---|---|---|
| 2014 | 44 | 164 | 7 | Ozone |
| 2015 | 42 | 169 | 4 | Ozone |
| 2016 | 43 | 174 | 9 | Ozone |
| 2017 | 41 | 207 | 4 | Ozone |
| 2018 | 40 | 218 | 8 | Ozone |
| 2019 | 39 | 224 | 4 | Ozone |
| 2020 | 37 | 275 | 6 | Ozone |
| 2021 | 42 | 245 | 9 | PM2.5 |
| 2022 | 40 | 256 | 6 | Ozone |
| 2023 | 42 | 246 | 12 | Ozone |
How This Grade Is Calculated
The AirHistory Air Quality Grade combines four signals: the 5-year median AQI (40% of the score), the 10-year trend direction (30%), the count of unhealthy days per year (20%), and the dominant pollutant type (10%). All four come directly from the EPA Air Quality System (AQS), which aggregates readings from federally certified monitors. Read the full methodology.
More about Allegan, Michigan
Allegan, Michigan has an Air Quality Grade of B (good) with a 5-year median AQI of 40. The dominant pollutant is Ground-Level Ozone, and air quality has been improving over the past decade.
The data source behind this answer is the EPA Air Quality System (AQS). Every figure on the page traces back to that source; the methodology page describes the inputs and the refresh cadence in full detail.
A practical caveat: the headline answer above reflects the most recent the EPA Air Quality System (AQS) vintage; underlying data is often revised for months after first publication, and the right reference for any specific decision is whichever vintage is current at the time of the decision. The as-of date is stamped on every page.
Source: EPA Outdoor Air Quality Data, 2026.