Air quality comparison · United States, 35.4 mi (57 km) apart
Baltimore vs Washington Air quality index (AQI) today
Baltimore has cleaner air than Washington right now: AQI 40 (Good) against 64 (Moderate).
That puts them in different EPA bands, so the health advice differs today. Over the past 6 days, on modeled daily averages, both averaged AQI 35. Baltimore has lost more forest since 2001. Washington has more tree cover.
United States
AQI 40
Good
Cleaner right now
- PM2.5
- 7.2 µg/m³
- Main pollutant
- PM2.5
- Source
- Ground station
- Reading
- Nov 11, 10:00 local
United States
AQI 64
Moderate
Cleaner right now
- PM2.5
- 16 µg/m³1.1× WHO guideline
- Main pollutant
- PM2.5
- Source
- Ground station
- Reading
- Nov 11, 10:00 local
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Baltimore40Washington64
Head to head
Baltimore vs Washington at a glance
Washington is ahead on 3 of 6 measures, and Baltimore on 2. The better figure in each row is marked.
| Baltimore | Washington | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 40 (better) | 64 |
| PM2.5Fine particles, µg/m³. | 7.2 (better) | 16 |
| Past week's averageUS AQI, 6 days. | 35 | 35 |
| Forest lost since 2001Within 10 km of the center. | 335 acres (136 ha) | 291 acres (118 ha) (better) |
| Tree coverWithin 1.2 mi (2 km) of the center. | 10.0% | 18.6% (better) |
| Trees still neededTo reach a healthy canopy. | 58.6K | 30.5K (better) |
Air quality today
What is the air like in Baltimore and Washington right now?
Baltimore has cleaner air than Washington right now: AQI 40 (Good) against 64 (Moderate). PM2.5 is setting the index in both.
Washington's PM2.5 is about 1.1× the WHO's 24-hour guideline of 15 µg/m³.
Both readings come from nearby ground stations.
BaltimoreWashington
Concentrations at the same moment as the index above, for the pollutants both places report. Lower is better. The dark marks on the PM2.5 and PM10 rows show the WHO's 24-hour guidelines (15 and 45 µg/m³).
The past week
Which had cleaner air over the past 6 days?
Over the past 6 days, on modeled daily averages, both averaged AQI 35. A single reading can catch a city on a bad afternoon; the week says whether it was the weather or the place.
- Cleaner days
- Baltimore2Washington1
- Average AQI
- Baltimore35Washington35
- Worst day, AQI
- Baltimore66Washington60
The daily numbers (6 days)
| Day | Baltimore | Washington |
|---|---|---|
| Nov 5 | 35 | 35 |
| Nov 6 | 30 | 30 |
| Nov 7 | 27 | 27 |
| Nov 8 | 29 | 30 |
| Nov 9 | 23 | 27 |
| Nov 10 | 66 | 60 |
Daily averages from the CAMS atmospheric model for both places, so the week compares like with like. They can differ from today's reading at the top of the page wherever that comes from a ground station.
What it means today
Is it safe to go outside in Baltimore and Washington today?
Baltimore (AQI 40, Good): Air quality is satisfactory for everyone.
Washington (AQI 64, Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
Exercise outdoors
- Baltimore
- A good day to be active outside.
- Washington
- Fine for most people; unusually sensitive people should take long or hard exercise easier.
Windows
- Baltimore
- Open them to air the house.
- Washington
- Fine to open; close them if you are sensitive to pollution.
Masks
- Baltimore
- Not needed.
- Washington
- Not needed for most people.
Air purifier
- Baltimore
- Not needed.
- Washington
- Worth running if you are sensitive.
Against everywhere else
How do Baltimore and Washington compare with the rest of the world?
Right now Baltimore's air is cleaner than 70% of the 5,420 places Airleaf tracks, and Washington's is cleaner than 44%. Within United States, that is 52% and 21% of its 308 measured places.
Cleaner air than…
- Baltimore
- Beats 70%
- Washington
- Beats 44%
More tree cover than…
- Baltimore
- Beats 21%
- Washington
- Beats 43%
Includes model estimates as well as station readings, so it can differ from our most polluted and cleanest air rankings, which use station readings only.
Deforestation · 2001–2025
Which has lost more forest, Baltimore or Washington?
Baltimore has lost more: about 335 acres (136 ha) of forest within 10 km of its center from 2001 to 2025, against 291 acres (118 ha) around Washington. 305 acres (123 ha) of that was cleared for good, for farms, mines or towns.
Measured within 10 km of each center, from the yearly satellite maps of forest loss: a wider circle than the one for tree cover, because forest is usually lost at a city's edges.
Worst year: 2017, with 48 acres (20 ha) lost.
Worst year: 2012, with 30 acres (12 ha) lost.
| Baltimore | Washington | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 335 acres (136 ha) | 291 acres (118 ha) (better) |
| Share of its forestOf what it had in 2000. | 2.5% | 1.4% (better) |
| Cleared for goodTurned into farms, mines or towns. | 305 acres (123 ha) | 259 acres (105 ha) (better) |
| Recent trend2021–2025 against the five years before. | Too little to call | Too little to call |
| Main known cause | Towns and roads (91%) | Towns and roads (89%) |
Satellite timelapses
Watch both change, year by year
A clear satellite photo a year of the land around each city. Press play, turn on the forest cleared since the first year, or drag the before and after.
Baltimore
2017: satellite photo from July 2017 of a 5 × 5 km area about 7 km south of the city center.
Washington
2017: satellite photo from July 2017 of a 5 × 5 km area in the city center.
Trees
Which has more trees, Baltimore or Washington?
Washington has more tree cover: 18.6% of the land within 1.2 mi (2 km) of its center against 10.0% around Baltimore, or about 49,727 trees against 29,280.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Baltimore | Washington | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 29.3K | 49.7K (better) |
| Trees still neededTo reach the target. Fewer is better. | 58.6K | 30.5K (better) |
| CO₂ absorbed each yearBy the trees already standing. | 644K kg | 1.1M kg (better) |
Tree cover on the satellite image
The same 1.2 mi (2 km) radius around each center, with the tree cover the satellite found marked on it.
Reading these numbers
How this comparison is made
Air quality index
The US EPA index, computed from current pollutant concentrations: ground stations where a place has them nearby, and the CAMS atmospheric model everywhere else. It moves hour to hour, so it is a snapshot rather than a verdict on either place. The guideline marks are from the WHO's 2021 air quality guidelines.
Trees and forest
Tree cover is the share of ground under canopy within 1.2 mi (2 km) of each center, read from Sentinel-2 satellite imagery at 10 m detail. It measures that circle, not the whole municipality, which is what makes the two comparable. Forest loss comes from the University of Maryland's Global Forest Change maps.
More on the method on the About Airleaf page.
Frequently asked
Baltimore vs Washington: your questions answered
Is Baltimore cleaner than Washington?
On air quality, yes, right now: Baltimore reads AQI 40 against 64, a gap of 24 points on the US EPA index. This is a live reading rather than an annual average, so it can reverse within a day. Over the past 6 days, on modeled daily averages, both averaged AQI 35.
Is it safe to exercise outdoors in Baltimore and Washington today?
In Baltimore, at AQI 40: Air quality is satisfactory for everyone. In Washington, at AQI 64: Unusually sensitive people should consider limiting long outdoor exertion.
Which has lost more forest, Baltimore or Washington?
Baltimore has lost more: about 335 acres (136 ha) of forest within 10 km of its center from 2001 to 2025, against 291 acres (118 ha) around Washington. 305 acres (123 ha) of that was cleared for good, for farms, mines or towns.
Which has more trees, Baltimore or Washington?
Washington has more tree cover: 18.6% of the land within 1.2 mi (2 km) of its center against 10.0% around Baltimore, or about 49,727 trees against 29,280. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Baltimore and Washington need?
Baltimore needs about 58,559 more to reach its canopy target of 30%, and Washington about 30,478 to reach 30%. The target starts at 30% of the land and rises where air quality is poor.
Why can two places 35.4 mi (57 km) apart read differently?
Air changes over short distances with traffic, industry, wind and hills, and each reading comes from the nearest ground stations or, where there are none, from a regional model. A gap of a few points between neighbors is within normal variation, while a gap that crosses an EPA band is worth noticing.
Are Baltimore and Washington measured the same way?
The method is the same: the US EPA index for air, and Sentinel-2 satellite imagery at 10 m detail over an identical radius for trees. Both readings come from nearby ground stations. Nothing is adjusted for population, city limits or climate.
How often does the Baltimore vs Washington comparison update?
The air readings refresh about once an hour, and each reading's local time is shown at the top of the page. Tree cover comes from the latest clear satellite image of each area (Aug 29, 2026 and Sep 9, 2026), and the forest figures are published yearly.
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