Baltimore Air Quality in August

Across 2019–2025, Baltimore's August air quality had a median AQI of 51 (Moderate) over 217 monitored days in the Baltimore-Columbia-Towson, MD area. 4.2% of August days (9 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 65.0% of days. The cleanest August on record here was 2025 (median AQI 45, 0 days above 100) and the worst was 2021 (median 55, 4 days above 100, peak AQI 140).

51
Median AQI
Moderate
4.2%
Days above AQI 100
9 of 217 days
87
90th percentile AQI
worst 1 day in 10
154
Peak AQI
Unhealthy
O3
Main pollutant
65.0% of days
47.0%
Good days
102 of 217
  • Good: 47.0%
  • Moderate: 48.8%
  • Unhealthy for Sensitive Groups: 3.7%
  • Unhealthy or worse: 0.5%

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QUICK ANSWER

How is the air in Baltimore in August?

Moderate on a typical day: median AQI 51 across 2019–2025, with 4.2% of August days above AQI 100. Ground-level ozone is the main driver.

  • 47.0% of August days were Good (AQI 0–50), 48.8% Moderate (51–100).
  • 9 days of 217 reached AQI 101+; the August peak was 154.
  • Best August: 2025; worst August: 2021.

Frequently asked questions

What is the air quality like in Baltimore in August?

Across 2019–2025, the median daily AQI in Baltimore in August was 51 (Moderate). 47.0% of days were Good, 48.8% Moderate, and 4.2% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.

Is August a good time for outdoor exercise in Baltimore?

A typical August day in Baltimore is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 24 of August days (4.2%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

Which pollutant causes Baltimore's August air quality problems?

Ground-level ozone set the daily AQI on 65.0% of August days in Baltimore. The highest August AQI recorded in 2019–2025 was 154 (Unhealthy), in 2021.

Baltimore August air quality, year by year

Baltimore August air quality by year (Baltimore-Columbia-Towson, MD, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
201931613122O3
20203151093O3
2021worst31554140O3
20223148097O3
202331510100O3
202431522154O3
2025cleanest3145093O3

What August air means in Baltimore

A typical August day in Baltimore is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 24 of August days (4.2%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

August's median AQI of 51 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 August AQI across every EPA metro area (104,152 metro-days, 2019–2025) is 45, so Baltimore runs above the national August norm; 4.2% of its August days topped AQI 100 versus 3.5% nationally (about the same).

August is part of Baltimore's summer season (June, July, August); the summer page pools all three months.

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 month 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.