Metro area air quality · 2024

Bay City, MI

Median AQI 37 (Good). 76.3% of monitored days rated Good across this metro's EPA monitoring network.

37
Median AQI
76.3%
Good-air days
0
Unhealthy days
56%
Cleaner than US metros

Aggregated from EPA Air Quality System (2024), 363 monitored days. EPA AQS → · NOAA →

Insights: Bay City, MI metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 37 over 363 measured days in 2024, which corresponds to a Good band and a Good metro-wide health grade. The monitored-day split lands at 277 Good days (76%), 86 Moderate (24%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 56 while the highest single-day reading hit 73 (Moderate). Metro residents averaged roughly 22.9 clean-air days per 30-day window across the reporting year.

Across the 2020–2024 trend window, good days shifted by -48 and the median AQI moved +15 points, which classifies the multi-year trajectory as worsening. The metro avoided any Unhealthy-tier days entirely, an outcome that typically reflects favorable wind patterns, lower industrial density, or effective regional emission controls. Metros with comparable AQI profiles include Albany-Schenectady-Troy, NY (76.5% good, AQI 37); Altoona, PA (80.9% good, AQI 37); Appleton, WI (79.5% good, AQI 37).

Air Quality Summary

Median AQI

37

Good

Good Days

76.3%

277 of 363 days

Max AQI

73

Moderate

Health Grade

Good

90th pct: 56

AQI Day Breakdown (2024)

Distribution of 363 monitored days across EPA AQI categories.

Good

277

76%

Moderate

86

24%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Good

The Bay City, MI metro area's air quality is rated Good based on 76.3% good air days. No unhealthy air days were recorded in 2024.

Air quality is generally acceptable. Unusually sensitive people should monitor real-time conditions at AirNow.gov during high-pollution events.

How does the Bay City, MI metro compare?

How Bay City, MI compares

Good-day share better than US avg
Bay City, MI 76.3%
Albany-Schenectady-Troy, NY 76.5%
US average 70.2%
Median AQI better than US avg
Bay City, MI 37
Albany-Schenectady-Troy, NY 37
US average 41
Unhealthy days / yr better than US avg
Bay City, MI 0
Albany-Schenectady-Troy, NY 0
US average 1

5-Year Air Quality Trend

Air quality is worsening in the Bay City, MI metro. Best year: 2020 (325 good days).

Year Good Moderate Unhealthy Median AQI
2020 325 40 0 22
2021 290 73 0 28
2022 287 67 0 32
2023 229 128 3 42
2024 277 86 0 37

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to Bay City, MI.

Albany-Schenectady-Troy, NY

AQI 37 · 76.5% good

37

Altoona, PA

AQI 37 · 80.9% good

37

Appleton, WI

AQI 37 · 79.5% good

37

Baraboo, WI

AQI 37 · 85.3% good

37

Burlington-South Burlington, VT

AQI 37 · 88.3% good

37

Cape Coral-Fort Myers, FL

AQI 37 · 92.1% good

37

More Air Quality Data

Explore EPA air quality rankings and guides across U.S. metros and counties.

Cleanest Metro Areas

U.S. metros ranked by their share of Good air-quality days.

Worst Air Quality

Counties and metros with the most unhealthy air days.

All Metro Areas

Annual AQI by CBSA for every monitored U.S. metro area.

Best and Worst City Air

What drives urban air quality and how metro areas compare.

Air Quality Guides

Learn more about air quality monitoring, pollutants, and health impacts.

Understanding AQI

What each AQI level means and who is most at risk.

Best & Worst City Air Quality

Metro area air quality rankings and what drives urban pollution.

Health Effects of Air Pollution

How PM2.5 and ozone exposure affects respiratory and cardiovascular health.

Frequently Asked Questions

What is the air quality in the Bay City, MI metro area? ▼
The Bay City, MI metro area has a median Air Quality Index (AQI) of 37, rated "Good." 76.3% of monitored days (277 out of 363) had good air quality in 2024.
How many unhealthy air days does Bay City, MI have? ▼
In 2024, the Bay City, MI metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 73.
Is air quality in Bay City, MI getting better or worse? ▼
Air quality in the Bay City, MI metro is worsening based on 5-year trends (2020-2024). Best year: 2020 with 325 good days. Worst year: 2023 with 229 good days.
What does AQI 37 mean for health? ▼
An AQI of 37 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
What is the 90th percentile AQI for Bay City, MI? ▼
The 90th percentile AQI for the Bay City, MI metro area is 56, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 73 (Moderate).
How does Bay City, MI compare to other metro areas? ▼
The Bay City, MI metro has 76.3% good air days. Similar metros: Albany-Schenectady-Troy, NY (76.5% good), Altoona, PA (80.9% good), Appleton, WI (79.5% good).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2024. The AQS collects ambient air monitoring data from state, local, and tribal monitoring agencies across the United States.

Metrics: Air Quality Index (AQI) is calculated using EPA-standard breakpoints for six criteria pollutants: PM2.5, PM10, Ozone, NO2, CO, and SO2. Median AQI, max AQI, and 90th percentile AQI are computed from daily measurements. Good days percentage reflects days with AQI 0–50.

Coverage: 501 metro areas (Core Based Statistical Areas). Only metros with active monitoring stations are included. Unmonitored areas are not represented.

Read our methodology , how this data is sourced, computed, and verified.

Source: U.S. EPA, AirNow / AQS Air Quality Index readings and pollutant concentrations · 2025