Loudoun, Virginia Air Quality
Loudoun County, Virginia (VA)
→ Stableover 10 years
10-Year AQI Trend
The solid line shows the median AQI each year. The dashed line shows the 90th percentile (worst 10% of days).
Air Quality Day Breakdown
Number of days per year in each EPA AQI category. Green = Good (AQI 0-50), Yellow = Moderate (51-100), Orange = Unhealthy for Sensitive Groups (101-150), Red = Unhealthy or worse (151+).
Year-by-Year Data
| Year | Median AQI | 90th Pct | Max AQI | Good Days | Moderate | Unhealthy+ | Pollutant |
|---|---|---|---|---|---|---|---|
| 2023 | 39 | 58 | 167 | 306 | 54 | 4 | Ozone |
| 2022 | 37 | 50 | 112 | 328 | 34 | 2 | Ozone |
| 2021 | 37 | 54 | 122 | 308 | 55 | 1 | Ozone |
| 2020 | 34 | 48 | 108 | 339 | 26 | 1 | Ozone |
| 2019 | 38 | 54 | 112 | 286 | 50 | 1 | Ozone |
| 2018 | 35 | 54 | 93 | 313 | 52 | 0 | Ozone |
| 2017 | 38 | 57 | 100 | 297 | 68 | 0 | Ozone |
| 2016 | 36 | 58 | 112 | 302 | 63 | 1 | Ozone |
| 2015 | 38 | 60 | 115 | 294 | 63 | 4 | Ozone |
| 2014 | 40 | 58 | 105 | 285 | 69 | 1 | Ozone |
What This Means for Loudoun County Residents
Loudoun, Virginia has received an Air Quality Grade of B (68/100) based on a decade of monitoring data from the EPA's air quality monitoring program. The current median AQI of 39 falls in the "Good" range.
The primary pollutant affecting this area is Ground-Level Ozone. Over the past 5 years, this area has averaged 2 unhealthy air quality days per year — days when sensitive groups (children, elderly, those with respiratory conditions) should limit outdoor activity. The American Lung Association's State of the Air report provides additional context on long-term health risks from air pollution exposure.
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Frequently Asked Questions
Loudoun, Virginia has a current median AQI of 39, which falls in the "Good" range. The area has received an Air Quality Grade of B (68/100) based on 10 years of EPA monitoring data.
Air quality in Loudoun, Virginia is stable over the past decade. The median AQI has changed by -1 points from 2014 to 2023.
Loudoun, Virginia averages 2 unhealthy air quality days per year over the past 5 years. On these days, sensitive groups including children, the elderly, and those with respiratory conditions should limit outdoor activity.
The primary pollutant affecting Loudoun, Virginia is Ground-Level Ozone. This is the dominant contributor to elevated AQI readings in the Loudoun County area.
Loudoun, Virginia averages 2 unhealthy air days per year. This is relatively low, making it a reasonable choice for asthma sufferers. The primary pollutant is Ground-Level Ozone, which is a known asthma trigger.
With a median AQI of 39 (Good), outdoor exercise in Loudoun, Virginia is generally safe year-round. Loudoun, Virginia averages 2 days per year when athletes should move workouts indoors.