Is the Air Quality Good in District of Columbia, District Of Columbia?
Mostly — air quality in District of Columbia, District Of Columbia is fair, not pristine. The city earns a Grade of C (fair) on a 5-year median AQI of 49 (Good), with 30 unhealthy-air days over five years (about 6 per year). Healthy adults are fine most of the time, but sensitive groups should watch the daily forecast.
Who Can Safely Breathe the Air in District of Columbia, District Of Columbia?
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.
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.
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 |
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.
More about 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.
The data source behind this answer is the EPA Air Quality System (AQS). Every figure on the page traces back to that source; the methodology page describes the inputs and the refresh cadence in full detail.
For readers turning this answer into action: cross-reference against the underlying the EPA Air Quality System (AQS) record before acting on time-sensitive decisions. The site renders the data as it was published; subsequent revisions can shift the picture, and the live federal data is always the authoritative current reference.
Source: EPA Outdoor Air Quality Data, 2026.