Baltimore Air Quality in Spring

Across 2019–2025, Baltimore's spring (March–May) air quality had a median AQI of 46 (Good) over 643 monitored days in the Baltimore-Columbia-Towson, MD area. 1.1% of spring days (7 of 643) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 75.6% of days. The cleanest spring on record here was 2020 (median AQI 44, 0 days above 100) and the worst was 2021 (median 48, 3 days above 100, peak AQI 122).

46
Median AQI
Good
1.1%
Days above AQI 100
7 of 643 days
67
90th percentile AQI
worst 1 day in 10
122
Peak AQI
Unhealthy for Sensitive Groups
O3
Main pollutant
75.6% of days
67.3%
Good days
433 of 643
  • Good: 67.3%
  • Moderate: 31.6%
  • Unhealthy for Sensitive Groups: 1.1%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Baltimore in spring?

Good on a typical day: median AQI 46 across 2019–2025, with 1.1% of spring days above AQI 100. Ground-level ozone is the main driver.

  • 67.3% of spring days were Good (AQI 0–50), 31.6% Moderate (51–100).
  • 7 days of 643 reached AQI 101+; the spring peak was 122.
  • Cleanest month: March; worst month: May.

Frequently asked questions

What is the air quality like in Baltimore in spring?

Across 2019–2025, the median daily AQI in Baltimore in spring was 46 (Good). 67.3% of days were Good, 31.6% Moderate, and 1.1% reached Unhealthy for Sensitive Groups or worse, based on 643 monitored days in EPA's Air Quality System.

Is spring a good time for outdoor exercise in Baltimore?

A typical spring day in Baltimore sits in the Good range (median AQI 46), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 91 of spring days (1.1%) reached AQI 101+ in 2019–2025.

Which pollutant causes Baltimore's spring air quality problems?

Ground-level ozone set the daily AQI on 75.6% of spring days in Baltimore. The highest spring AQI recorded in 2019–2025 was 122 (Unhealthy for Sensitive Groups), in 2021.

Baltimore spring air quality, year by year

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

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20199250080O3
2020cleanest9144064O3
2021worst92483122O3
20229245097O3
202392492112O3
202492452115O3
20259244090O3

What spring air means in Baltimore

A typical spring day in Baltimore sits in the Good range (median AQI 46), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 91 of spring days (1.1%) reached AQI 101+ in 2019–2025.

Spring's median AQI of 46 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 Spring AQI across every EPA metro area (307,196 metro-days, 2019–2025) is 43, so Baltimore runs in line with the national Spring norm; 1.1% of its Spring days topped AQI 100 versus 0.8% nationally (about the same).

Within the season, March is the cleanest month (median AQI 45, 0.0% of days above 100) and May the worst (median 48, 2.8% 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.