Metro area air quality · 2025
Baltimore-Columbia-Towson, MD
Median AQI 48 (Good). 58.1% of monitored days rated Good across this metro's EPA monitoring network.
- 48
- Median AQI
- 58.1%
- Good-air days
- 0
- Unhealthy days
- 22%
- Cleaner than US metros
Baltimore-Columbia-Towson, MD posted a 2025 median AQI of 48 (Good) with 58.1% Good days
According to the U.S. EPA Air Quality System, the Baltimore-Columbia-Towson, MD CBSA recorded a median AQI of 48 across 365 monitored days in 2025, with 58.1% rated Good and 0 unhealthy or worse. This is an annual metro comparison, not a live advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US metros
- The Baltimore-Columbia-Towson, MD CBSA's 58.1% Good-day share places it cleaner than 22% of US metros in 2025.
- Closest median-AQI peer
- Boulder, CO (58.4% Good, median AQI 48) is the closest nationwide median-AQI peer to Baltimore-Columbia-Towson, MD.
- 2020–2025 Good-day shift
- Baltimore-Columbia-Towson, MD's Good-day share moved -5.2 points from 2020 to 2025 (median AQI +2).
- Median AQI
- Median AQI: 48
Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →
The verdict
Baltimore-Columbia-Towson, MD lands in the lower Good-day tercile (58.1% Good), a thinner clean-air share than most CBSA peers here. On the EPA scale the metro runs good, among the more polluted US metros, with a median AQI of 48 and 58.1% of 365 monitored days in the Good band.
- 48
- median AQI · Good
- 58.1%
- days rated Good
- 22%
- cleaner than US metros
- 143
- worst single reading
No day crossed into the Unhealthy tier across the metro's monitors in 2025.
Annual release change
What changed in the 2025 EPA annual release
- Baltimore-Columbia-Towson, MD metro's Good-day share fell from 60.6% to 58.9% between the 2024 and 2025 EPA annual releases, a change of -1.7 percentage points.
- Baltimore-Columbia-Towson, MD metro's peak single-day AQI fell from 154 to 143 between the 2024 and 2025 EPA annual releases, a change of -11 points.
- Baltimore-Columbia-Towson, MD metro's Unhealthy-category days fell from 1 to 0 between the 2024 and 2025 EPA annual releases, a change of -1 days.
Baltimore-Columbia-Towson, MD lands in the lower Good-day tercile (58.1% Good), a thinner clean-air share than most CBSA peers here. Signature read: 58.1% Good-day share (low tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 48 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 212 Good (58%), 148 Moderate (41%), and 5 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 69; the highest single-day reading hit 143 (USG).
Across 2020–2025, Good-day share shifted -5.2 points and median AQI moved +2 (worsening). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Boulder, CO (58.4% good, AQI 48); Columbus, GA-AL (53.4% good, AQI 48); Durango, CO (60.8% good, AQI 48).
Air Quality Summary
Median AQI
48
Good
Good Days
58.1%
212 of 365 days
Max AQI
143
USG
Health Grade
Moderate
90th pct: 69
AQI Day Breakdown (2025)
Distribution of 365 monitored days across EPA AQI categories.
Good
212
58%
Moderate
148
41%
USG
5
1%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Baltimore-Columbia-Towson, MD metro area's air quality is rated Moderate based on 58.1% good air days. No unhealthy air days were recorded in 2025.
Air quality is generally acceptable. Unusually sensitive people should monitor real-time conditions at AirNow.gov during high-pollution events.
How does the Baltimore-Columbia-Towson, MD metro compare?
How Baltimore-Columbia-Towson, MD compares
5-Year Air Quality Trend
Air quality is worsening in the Baltimore-Columbia-Towson, MD metro. Highest Good-day share: 2020 (64.1%, 232 of 362 monitored days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 232 | 130 | 0 | 46 | 119 |
| 2021 | 169 | 181 | 0 | 52 | 140 |
| 2022 | 200 | 163 | 0 | 49 | 122 |
| 2023 | 201 | 147 | 3 | 49 | 205 |
| 2024 | 215 | 139 | 1 | 47 | 154 |
| 2025 | 212 | 148 | 0 | 48 | 143 |
Metros with a similar median AQI
CBSA peers nationwide whose annual median AQI sits near Baltimore-Columbia-Towson, MD (48).
Boulder, CO
Median AQI 48 · 58.4% Good-day share
Columbus, GA-AL
Median AQI 48 · 53.4% Good-day share
Durango, CO
Median AQI 48 · 60.8% Good-day share
Greenville-Anderson-Mauldin, SC
Median AQI 48 · 55.3% Good-day share
Knoxville, TN
Median AQI 48 · 56.4% Good-day share
Lake City, FL
Median AQI 48 · 57.3% Good-day share
Metros with similar unhealthy-day exposure
A second relationship type: metros whose unhealthy-or-worse day count is closest to Baltimore-Columbia-Towson, MD's 0 (independent of median AQI).
Aberdeen, SD
0 unhealthy-or-worse days · median AQI 27
Aberdeen, WA
0 unhealthy-or-worse days · median AQI 22
Adrian, MI
0 unhealthy-or-worse days · median AQI 41
Akron, OH
0 unhealthy-or-worse days · median AQI 45
Albany, GA
0 unhealthy-or-worse days · median AQI 46
Albany, OR
0 unhealthy-or-worse days · median AQI 27
Frequently Asked Questions
How many unhealthy air days does Baltimore-Columbia-Towson, MD have? ▼
What is the air quality in the Baltimore-Columbia-Towson, MD metro area? ▼
Is air quality in Baltimore-Columbia-Towson, MD getting better or worse? ▼
What does AQI 48 mean for health? ▼
How does Baltimore-Columbia-Towson, MD compare to other metro areas? ▼
What is the 90th percentile AQI for Baltimore-Columbia-Towson, MD? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Baltimore-Columbia-Towson, MD, 2025. See our methodology for how AQI, median, and coverage figures are computed.
Read our methodology , how this data is sourced, computed, and verified.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary, Baltimore-Columbia-Towson, MD · 2020–2025