St. Paul Air Quality in March
Across 2019–2025, St. Paul's March air quality had a median AQI of 47 (Good) over 217 monitored days in the Minneapolis-St. Paul-Bloomington, MN-WI area. 0.0% of March days (0 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 51.2% of days. The cleanest March on record here was 2022 (median AQI 41, 0 days above 100) and the worst was 2019 (median 58, 0 days above 100, peak AQI 87).
- Good: 56.7%
- Moderate: 43.3%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
Reduce Indoor Ozone in St. Paul
Today's main pollutant in St. Paul is ground-level ozone (AQI 25). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How is the air in St. Paul in March?
Good on a typical day: median AQI 47 across 2019–2025, with 0.0% of March days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓56.7% of March days were Good (AQI 0–50), 43.3% Moderate (51–100).
- ✓0 days of 217 reached AQI 101+; the March peak was 89.
- ✓Best March: 2022; worst March: 2019.
Frequently asked questions
What is the air quality like in St. Paul in March?▾
Across 2019–2025, the median daily AQI in St. Paul in March was 47 (Good). 56.7% of days were Good, 43.3% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is March a good time for outdoor exercise in St. Paul?▾
A typical March day in St. Paul sits in the Good range (median AQI 47), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of March days reached AQI 101+ in 2019–2025.
Which pollutant causes St. Paul's March air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 51.2% of March days in St. Paul. The highest March AQI recorded in 2019–2025 was 89 (Moderate), in 2019.
St. Paul March air quality, year by year
St. Paul March air quality by year (Minneapolis-St. Paul-Bloomington, MN-WI, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019worst | 31 | 58 | 0 | 87 | PM2.5 |
| 2020 | 31 | 46 | 0 | 66 | PM2.5 |
| 2021 | 31 | 53 | 0 | 89 | PM2.5 |
| 2022cleanest | 31 | 41 | 0 | 69 | O3 |
| 2023 | 31 | 50 | 0 | 80 | O3 |
| 2024 | 31 | 42 | 0 | 68 | O3 |
| 2025 | 31 | 42 | 0 | 69 | O3 |
What March air means in St. Paul
A typical March day in St. Paul sits in the Good range (median AQI 47), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of March days reached AQI 101+ in 2019–2025.
March's median AQI of 47 is in line with St. Paul's whole-year median of 50, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median March AQI across every EPA metro area (102,455 metro-days, 2019–2025) is 42, so St. Paul runs above the national March norm; 0.0% of its March days topped AQI 100 versus 0.4% nationally (about the same).
March is part of St. Paul's spring season (March, April, May); the spring page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in St. Paul
The latest EPA AirNow observation puts St. Paul's AQI at 25 (O3). The figures above are multi-year month statistics, not today's reading.
View current St. Paul air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Minneapolis-St. Paul-Bloomington, MN-WI), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.