What Is the Air Quality in District of Columbia, District Of Columbia?
District of Columbia, District Of Columbia has an Air Quality Grade of C (fair) with a 5-year median AQI of 49. The dominant pollutant is Fine Particulate Matter (PM2.5), and air quality has been improving over the past decade.
District of Columbia, District Of Columbia Air Quality Snapshot
| Air Quality Grade | C63/100 |
| 5-Year Median AQI | 49 (Good) |
| Most Recent Median AQI (2023) | 50 (Good) |
| Dominant Pollutant | Fine Particulate Matter (PM2.5) |
| 10-Year Trend | Improving (-0.63 AQI/yr) |
| Unhealthy Days (last 5 yr) | 30 |
| National Rank (cleanest = #1) | #894 of 1,020 (88th most polluted percentile) |
What Does the C Grade Mean?
District of Columbia, District Of Columbia earns a C — air quality is fair, but not great. With a 5-year median AQI of 49, the city sees a meaningful number of "Moderate" days each year, when the EPA flags air as a concern for unusually sensitive people.
District of Columbia, District Of Columbia's 5-year median AQI of 49 is 8 points above the national average of 41 — meaningfully more polluted than the typical U.S. metro tracked here. Within District Of Columbia, District of Columbia, District Of Columbia's air quality is roughly typical for the state, where the average city posts a 5-year median AQI of 49.
What's in District of Columbia, District Of Columbia's Air?
The dominant pollutant in District of Columbia, District Of Columbia is Fine Particulate Matter (PM2.5). Fine particulate matter — particles less than 2.5 micrometers across — comes mostly from combustion: vehicle exhaust, wildfire smoke, residential wood burning, and industrial emissions. Because these particles are small enough to enter the bloodstream, PM2.5 is the pollutant most strongly linked to cardiovascular disease, respiratory illness, and premature death.
Days by Dominant Pollutant (2023)
| Pollutant | Days as Dominant | Share of Year |
|---|---|---|
| Fine Particulate Matter (PM2.5) | 195 | 53% |
| Ground-Level Ozone | 162 | 44% |
| Nitrogen Dioxide | 7 | 2% |
| Coarse Particulate Matter (PM10) | 1 | 0% |
Is the Air Getting Better or Worse?
Air quality in District of Columbia, District Of Columbia has been improving over the past decade, with median AQI dropping by roughly 0.6 points per year. That is consistent with the broader national pattern — most U.S. metros have seen steady reductions in particulate and ozone pollution since the 2010s as cleaner vehicles and power plants come online.
In 2014, District of Columbia, District Of Columbia posted a median AQI of 53. By 2023 that figure was 50 — a drop of 3 AQI points cleaner across 10 years of EPA records.
Year-by-Year AQI in District of Columbia, District Of Columbia
| Year | Median AQI | Good Days | Unhealthy Days | Dominant Pollutant |
|---|---|---|---|---|
| 2014 | 53 | 145 | 4 | PM2.5 |
| 2015 | 53 | 140 | 5 | PM2.5 |
| 2016 | 53 | 140 | 7 | PM2.5 |
| 2017 | 56 | 101 | 4 | PM2.5 |
| 2018 | 52 | 167 | 6 | PM2.5 |
| 2019 | 49 | 195 | 5 | PM2.5 |
| 2020 | 44 | 248 | 1 | PM2.5 |
| 2021 | 51 | 172 | 8 | PM2.5 |
| 2022 | 49 | 198 | 4 | PM2.5 |
| 2023 | 50 | 189 | 12 | PM2.5 |
Health Context for District of Columbia, District Of Columbia
Across the past five years, this area has logged 30 days where AQI rose into the "Unhealthy for Sensitive Groups" range or worse — about 6 days per year. That is roughly typical for a U.S. metro, with most caution days clustered in summer (ozone) or wildfire season.
Healthy adults can continue normal outdoor activity in most weather, but should pay attention to AQI alerts during the worst pollution windows. People with asthma, heart disease, or pregnancy should reduce prolonged or intense outdoor exertion on flagged days, and consider running an indoor HEPA air cleaner during peak season. Because PM2.5 penetrates deep into the lungs and bloodstream, an N95 or KN95 mask provides meaningful protection on smoky or high-particulate days — surgical masks do not.
How This Grade Is Calculated
The AirHistory Air Quality Grade combines four signals: the 5-year median AQI (40% of the score), the 10-year trend direction (30%), the count of unhealthy days per year (20%), and the dominant pollutant type (10%). All four come directly from the EPA Air Quality System (AQS), which aggregates readings from federally certified monitors. Read the full methodology.
District of Columbia, District Of Columbia has an Air Quality Grade of C (fair) with a 5-year median AQI of 49. The dominant pollutant is Fine Particulate Matter (PM2.5), and air quality has been improving over the past decade.
This answer pulls from the EPA Air Quality System (AQS), the authoritative federal source for U.S. air quality and pollution monitoring. The headline number above is the direct answer; what follows is the additional context most readers need to use the answer for a real decision rather than just a fact lookup.
A practical caveat: the headline answer above reflects the most recent the EPA Air Quality System (AQS) vintage; underlying data is often revised for months after first publication, and the right reference for any specific decision is whichever vintage is current at the time of the decision. The as-of date is stamped on every page.
Source: EPA Outdoor Air Quality Data, 2026.