Baltimore Air Quality in 2021
In 2021, Baltimore's air quality (Baltimore-Columbia-Towson, MD area) had a median daily AQI of 52 (Moderate) across 365 monitored days. 15 days (4.1%) reached Unhealthy for Sensitive Groups or worse, 169 were Good, and the year's peak AQI was 140 (Unhealthy for Sensitive Groups). Fine particulate matter (PM2.5) set the daily AQI on 203 of those days. The cleanest month of 2021 was January (median AQI 42, 0 days above 100) and the worst was June (median 51, 4 days above 100, peak 122).
- Good: 46.3%
- Moderate: 49.6%
- Unhealthy for Sensitive Groups: 4.1%
- Unhealthy or worse: 0.0%
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How was Baltimore's air quality in 2021?
Moderate on a typical day: median AQI 52, with 15 days above AQI 100 out of 365 monitored — the 6th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2021: 140 (Unhealthy for Sensitive Groups).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 203 days.
- ✓Cleanest month: January; worst: June.
Frequently asked questions
What was the average AQI in Baltimore in 2021?▾
EPA's Air Quality System puts Baltimore's (Baltimore-Columbia-Towson, MD) median daily AQI for 2021 at 52, which is Moderate. 15 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 140.
Which month had the worst air quality in Baltimore in 2021?▾
The cleanest month of 2021 was January (median AQI 42, 0 days above 100) and the worst was June (median 51, 4 days above 100, peak 122).
Was 2021 a good or bad year for Baltimore's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 6th cleanest by days above AQI 100. 2021's median of 52 is above the area's typical annual median of 49.
Baltimore month by month in 2021
Baltimore air quality month by month, 2021 (Baltimore-Columbia-Towson, MD, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| Januarycleanest | 31 | 42 | 0 | 74 | PM2.5 |
| February | 28 | 54 | 0 | 80 | PM2.5 |
| March | 31 | 46 | 0 | 84 | O3 |
| April | 30 | 51 | 0 | 87 | O3 |
| May | 31 | 46 | 3 | 122 | O3 |
| Juneworst | 30 | 51 | 4 | 122 | O3 |
| July | 31 | 63 | 4 | 126 | PM2.5 |
| August | 31 | 55 | 4 | 140 | O3 |
| September | 30 | 46 | 0 | 84 | PM2.5 |
| October | 31 | 51 | 0 | 59 | PM2.5 |
| November | 30 | 55 | 0 | 80 | PM2.5 |
| December | 31 | 54 | 0 | 63 | PM2.5 |
How 2021 compares
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 6th cleanest by days above AQI 100.
2021's median of 52 is above the area's typical annual median of 49.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Baltimore
The latest EPA AirNow observation puts Baltimore's AQI at 31 (PM2.5). The figures above are multi-year annual 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.