Baltimore Air Quality in Winter
Across 2019–2025, Baltimore's winter (December–February) air quality had a median AQI of 47 (Good) over 632 monitored days in the Baltimore-Columbia-Towson, MD area. 0.2% of winter days (1 of 632) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 80.1% of days. The cleanest winter on record here was 2020 (median AQI 42, 0 days above 100) and the worst was 2019 (median 43, 1 day above 100, peak AQI 123).
- Good: 55.2%
- Moderate: 44.6%
- Unhealthy for Sensitive Groups: 0.2%
- Unhealthy or worse: 0.0%
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How is the air in Baltimore in winter?
Good on a typical day: median AQI 47 across 2019–2025, with 0.2% of winter days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓55.2% of winter days were Good (AQI 0–50), 44.6% Moderate (51–100).
- ✓1 day of 632 reached AQI 101+; the winter peak was 123.
- ✓Cleanest month: January; worst month: December.
Frequently asked questions
What is the air quality like in Baltimore in winter?▾
Across 2019–2025, the median daily AQI in Baltimore in winter was 47 (Good). 55.2% of days were Good, 44.6% Moderate, and 0.2% reached Unhealthy for Sensitive Groups or worse, based on 632 monitored days in EPA's Air Quality System.
Is winter a good time for outdoor exercise in Baltimore?▾
A typical winter day in Baltimore 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 winter days reached AQI 101+ in 2019–2025.
Which pollutant causes Baltimore's winter air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 80.1% of winter days in Baltimore. The highest winter AQI recorded in 2019–2025 was 123 (Unhealthy for Sensitive Groups), in 2019.
Baltimore winter air quality, year by year
Baltimore winter air quality by year (Baltimore-Columbia-Towson, MD, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019worst | 90 | 43 | 1 | 123 | PM2.5 |
| 2020cleanest | 91 | 42 | 0 | 84 | PM2.5 |
| 2021 | 90 | 53 | 0 | 80 | PM2.5 |
| 2022 | 90 | 52 | 0 | 78 | PM2.5 |
| 2023 | 90 | 43 | 0 | 78 | PM2.5 |
| 2024 | 91 | 46 | 0 | 81 | PM2.5 |
| 2025 | 90 | 49 | 0 | 75 | PM2.5 |
What winter air means in Baltimore
A typical winter day in Baltimore 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 winter days reached AQI 101+ in 2019–2025.
Winter's median AQI of 47 is in line with Baltimore's whole-year median of 49, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median Winter AQI across every EPA metro area (278,620 metro-days, 2019–2025) is 40, so Baltimore runs above the national Winter norm; 0.2% of its Winter days topped AQI 100 versus 0.6% nationally (about the same).
Within the season, January is the cleanest month (median AQI 43, 0.0% of days above 100) and December the worst (median 49, 0.5% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Baltimore
The latest EPA AirNow observation puts Baltimore's AQI at 43 (PM2.5). The figures above are multi-year season statistics, not today's reading.
View current Baltimore air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Baltimore-Columbia-Towson, MD), 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.