Air quality comparison · United States, 594.0 mi (956 km) apart
Chicago vs Washington Air quality index (AQI) today
Washington has cleaner air than Chicago right now: AQI 58 (Moderate) against 119 (Unhealthy for sensitive groups).
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. Washington has lost more forest since 2001. Washington has more tree cover.
United States
AQI 119
Unhealthy for sensitive groups
Cleaner right now
- PM2.5
- 43 µg/m³2.9× WHO guideline
- Main pollutant
- PM2.5
- Source
- Ground station
- Reading
- Nov 11, 10:00 local
United States
AQI 58
Moderate
Cleaner right now
- PM2.5
- 13 µg/m³
- Main pollutant
- PM2.5
- Source
- Ground station
- Reading
- Nov 11, 11:00 local
Updated . Lower is better on the US EPA index: 0–50 is Good, above 300 is Hazardous. Measured by Airleaf.
Chicago119Washington58
Head to head
Chicago vs Washington at a glance
Washington is ahead on 4 of 6 measures, and Chicago on 1. The better figure in each row is marked.
| Chicago | Washington | |
|---|---|---|
| Air quality nowUS AQI. Lower is better. | 119 | 58 (better) |
| PM2.5Fine particles, µg/m³. | 43 | 13 (better) |
| Past week's averageUS AQI, 6 days. | 35 | 35 |
| Forest lost since 2001Within 10 km of the center. | 5 acres (2 ha) (better) | 291 acres (118 ha) |
| Tree coverWithin 1.2 mi (2 km) of the center. | 8.2% | 18.6% (better) |
| Trees still neededTo reach a healthy canopy. | 82.9K | 30.5K (better) |
Air quality today
What is the air like in Chicago and Washington right now?
Washington has cleaner air than Chicago right now: AQI 58 (Moderate) against 119 (Unhealthy for sensitive groups). PM2.5 is setting the index in both.
Chicago's PM2.5 is about 2.9× the WHO's 24-hour guideline of 15 µg/m³.
Both readings come from nearby ground stations.
ChicagoWashington
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
- Chicago3Washington3
- Average AQI
- Chicago35Washington35
- Worst day, AQI
- Chicago52Washington60
The daily numbers (6 days)
| Day | Chicago | Washington |
|---|---|---|
| Nov 5 | 32 | 35 |
| Nov 6 | 11 | 30 |
| Nov 7 | 32 | 27 |
| Nov 8 | 35 | 30 |
| Nov 9 | 47 | 27 |
| Nov 10 | 52 | 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 Chicago and Washington today?
Chicago (AQI 119, Unhealthy for sensitive groups): Sensitive groups should limit long or intense outdoor activity.
Washington (AQI 58, Moderate): Unusually sensitive people should consider limiting long outdoor exertion.
Exercise outdoors
- Chicago
- Children, older adults and people with asthma or heart disease should cut down long or hard exercise.
- Washington
- Fine for most people; unusually sensitive people should take long or hard exercise easier.
Windows
- Chicago
- Close them to keep the outside air out.
- Washington
- Fine to open; close them if you are sensitive to pollution.
Masks
- Chicago
- Sensitive groups: an N95 outdoors.
- Washington
- Not needed for most people.
Air purifier
- Chicago
- Run one, especially in bedrooms.
- Washington
- Worth running if you are sensitive.
Against everywhere else
How do Chicago and Washington compare with the rest of the world?
Right now Chicago's air is cleaner than 16% of the 5,420 places Airleaf tracks, and Washington's is cleaner than 50%. Within United States, that is 1% and 22% of its 308 measured places.
Cleaner air than…
- Chicago
- Beats 16%
- Washington
- Beats 50%
More tree cover than…
- Chicago
- Beats 17%
- 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, Chicago or Washington?
Washington has lost more: about 291 acres (118 ha) of forest within 10 km of its center from 2001 to 2025, against 5 acres (2 ha) around Chicago. 259 acres (105 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: 2003, with under 1 ha lost.
Worst year: 2012, with 30 acres (12 ha) lost.
| Chicago | Washington | |
|---|---|---|
| Forest lost since 2001Cleared, burned or logged. | 5 acres (2 ha) (better) | 291 acres (118 ha) |
| Share of its forestOf what it had in 2000. | under 1% (better) | 1.4% |
| Cleared for goodTurned into farms, mines or towns. | under 1 ha (better) | 259 acres (105 ha) |
| Recent trend2021–2025 against the five years before. | Too little to call | Too little to call |
| Main known cause | Towns and roads (42%) | 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.
Chicago
2018: satellite photo from August 2018 of a 5 × 5 km area in 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, Chicago or Washington?
Washington has more tree cover: 18.6% of the land within 1.2 mi (2 km) of its center against 8.2% around Chicago, or about 49,727 trees against 25,375.
The dark mark is each place's canopy target: 30% of the land, raised where air quality is poor.
| Chicago | Washington | |
|---|---|---|
| Trees standingEstimated from the canopy area. | 25.4K | 49.7K (better) |
| Trees still neededTo reach the target. Fewer is better. | 82.9K | 30.5K (better) |
| CO₂ absorbed each yearBy the trees already standing. | 558K 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
Chicago vs Washington: your questions answered
Is Washington cleaner than Chicago?
On air quality, yes, right now: Washington reads AQI 58 against 119, a gap of 61 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 Chicago and Washington today?
In Chicago, at AQI 119: Sensitive groups should limit long or intense outdoor activity. In Washington, at AQI 58: Unusually sensitive people should consider limiting long outdoor exertion.
Which has lost more forest, Chicago or Washington?
Washington has lost more: about 291 acres (118 ha) of forest within 10 km of its center from 2001 to 2025, against 5 acres (2 ha) around Chicago. 259 acres (105 ha) of that was cleared for good, for farms, mines or towns.
Which has more trees, Chicago or Washington?
Washington has more tree cover: 18.6% of the land within 1.2 mi (2 km) of its center against 8.2% around Chicago, or about 49,727 trees against 25,375. Both figures describe the same-sized circle of ground around each center, not the whole municipality.
How many more trees do Chicago and Washington need?
Chicago needs about 82,932 more to reach its canopy target of 35%, and Washington about 30,478 to reach 30%. The target starts at 30% of the land and rises where air quality is poor.
Are Chicago 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 Chicago 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 (Sep 11, 2026 and Sep 9, 2026), and the forest figures are published yearly.
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