Stephens City, Virginia Air Quality
Stephens City has a median AQI of 42, earning an air quality grade of A- — excellent air quality that ranks better than 44% of US cities. Air quality has remained relatively stable over the past decade. Particulate matter (PM2.5) is the primary concern, often linked to vehicle traffic, industrial activity, and wildfire smoke. In 2025, Stephens City recorded 200 good air quality days (70% of monitored days).
Population: 2,393 • County: Frederick
Current AQI
Quick Facts
| Current AQI | 18 — Good |
| Air Quality Grade | A- |
| Median AQI (2025) | 42 |
| vs. U.S. Cities | Better than 44% |
| Primary Pollutant | PM2.5 |
| Unhealthy Days/Year | 0 |
| 10-Year Trend | → Stable |
| Data Source | EPA AQS (historical) · AirNow (live) |
Health Recommendation
Air quality is satisfactory, and air pollution poses little or no risk.
It's a great day to be active outside!
5-Day AQI Forecast
Last 90 Days
Current Pollutant Levels
Real-time data from EPA AirNow
Local Air Quality Context
Air quality data for Stephens City is sourced from the ASHBURN monitoring area, located approximately 40 miles from city center. This EPA-certified station continuously tracks particulate matter (PM2.5), the primary driver of air quality alerts in this area.
Stephens City tends to see elevated PM2.5 readings during fall and winter months when temperature inversions trap pollutants near the surface. Wood burning, vehicle exhaust, and reduced wind speeds compound the effect. Residents with respiratory conditions should monitor forecasts closely between November and February.
AQI Trend (10 Years)
Air Quality Days by Year
Stephens City Median AQI by Year
Annual EPA air quality data for Stephens City — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 42 | 200 | — | 85 | PM2.5 |
| 2024 | 41 | 264 | 1 | 102 | PM2.5 |
| 2023 | 44 | 240 | 9 | 185 | PM2.5 |
| 2022 | 43 | 234 | — | 89 | PM2.5 |
| 2021 | 44 | 222 | — | 98 | PM2.5 |
| 2020 | 39 | 249 | — | 81 | PM2.5 |
| 2019 | 42 | 277 | — | 96 | PM2.5 |
| 2018 | 40 | 267 | — | 87 | PM2.5 |
| 2017 | 42 | 253 | — | 80 | PM2.5 |
| 2016 | 42 | 256 | — | 90 | PM2.5 |
Source: EPA Air Quality System (AQS) annual summaries. "Unhealthy Days" includes Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, and Hazardous categories.
2025 Air Quality Summary
Primary Pollutant Days (2025)
Days when each pollutant was the primary driver of AQI. Learn about pollutants →
Frequently Asked Questions About Stephens City Air Quality
What is the air quality in Stephens City today?
The current AQI in Stephens City is 18, rated "Good". Air quality is good — outdoor activity is safe for everyone today. Air quality is satisfactory, and air pollution poses little or no risk.
Is air quality in Stephens City getting better or worse?
Air quality in Stephens City has been stable. The median AQI has remained stable at around 42 over the past decade.
What is the most common air pollutant in Stephens City?
PM2.5 is the primary air pollutant in Stephens City, responsible for 172 days (61% of monitored days) in 2025. Particulate matter originates from vehicle exhaust, wildfires, construction, and industrial activity.
How many unhealthy air days does Stephens City have per year?
In 2025, Stephens City recorded 70% good air quality days (200 days) out of 284 monitored days. There were 0 Unhealthy for Sensitive Groups days and 0 Unhealthy days (AQI above 100). The highest single-day AQI recorded was 85.
What air quality grade does Stephens City receive?
Stephens City receives an air quality grade of A-, placing it better than 44% of US cities. This is based on a median AQI of 42 in 2025, with 200 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 44% of US cities
Nearby Cities
Get AQI Alerts
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National Rankings
See how Stephens City compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Stephens City
Stephens City sees its worst PM2.5 during winter temperature inversions when particulates get trapped near ground level. A unit with True HEPA and an auto-mode sensor is most effective for responding to these spikes.
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