Triangle, Virginia Air Quality
Triangle has a median AQI of 38, earning an air quality grade of A — excellent air quality that ranks better than 70% of US cities. Air quality has been trending worse over the past decade, a concern for local residents and health officials. Ground-level ozone is the primary concern, typically peaking on warm sunny days due to vehicle and industrial emissions. In 2025, Triangle recorded 256 good air quality days (94% of monitored days).
Population: 10,450 • County: Prince William
Current AQI
Quick Facts
| Current AQI | 26 — Good |
| Air Quality Grade | A |
| Median AQI (2025) | 38 |
| vs. U.S. Cities | Better than 70% |
| Primary Pollutant | Ozone |
| Unhealthy Days/Year | 0 |
| 10-Year Trend | ↓ Worsening |
| 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 Triangle is sourced from the Northern VA Near Road monitoring area, located approximately 17 miles from city center. This EPA-certified station continuously tracks ground-level ozone, the primary driver of air quality alerts in this area.
Triangle typically sees its worst air quality during summer afternoons when heat and sunlight drive ground-level ozone formation from vehicle and industrial emissions. Morning readings are generally 15–25 points lower than afternoon peaks. Outdoor activity is best planned for early morning on high-ozone days.
AQI Trend (10 Years)
Air Quality Days by Year
Triangle Median AQI by Year
Annual EPA air quality data for Triangle — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 38 | 256 | — | 87 | Ozone |
| 2024 | 35 | 339 | — | 87 | Ozone |
| 2023 | 37 | 329 | 3 | 129 | Ozone |
| 2022 | 35 | 337 | — | 93 | Ozone |
| 2021 | 35 | 333 | 1 | 119 | Ozone |
| 2020 | 32 | 357 | — | 74 | Ozone |
| 2019 | 36 | 347 | — | 100 | Ozone |
| 2018 | 32 | 316 | — | 100 | Ozone |
| 2017 | 34 | 333 | — | 97 | Ozone |
| 2016 | 31 | 323 | 3 | 112 | Ozone |
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 Triangle Air Quality
What is the air quality in Triangle today?
The current AQI in Triangle is 26, 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 Triangle getting better or worse?
Air quality in Triangle has been worsening. The median AQI has risen 7 points (from 31 in 2016 to 38 in 2025), a concern for local health officials.
What is the most common air pollutant in Triangle?
Ozone is the primary air pollutant in Triangle, responsible for 270 days (99% of monitored days) in 2025. Ground-level ozone forms when sunlight reacts with emissions from vehicles and industry, typically peaking on hot summer afternoons.
How many unhealthy air days does Triangle have per year?
In 2025, Triangle recorded 94% good air quality days (256 days) out of 272 monitored days. There were 0 Unhealthy for Sensitive Groups days and 0 Unhealthy days (AQI above 100). The highest single-day AQI recorded was 87.
What air quality grade does Triangle receive?
Triangle receives an air quality grade of A, placing it better than 70% of US cities. This is based on a median AQI of 38 in 2025, with 256 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 70% of US cities
Nearby Cities
Get AQI Alerts
Receive notifications when air quality changes in Triangle
National Rankings
See how Triangle compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Triangle
Triangle has a summer ozone problem — hot afternoons push AQI into Moderate or higher as sunlight converts vehicle and industrial emissions into ground-level ozone. Activated carbon and PECO filters chemically neutralize ozone rather than just trapping particles.
Blueair Blue Pure 211+
High performance for large rooms with simple operation.
- ✓Good room size match
- ✓Recommended for your air quality
- ✓High performance
We may earn a commission from purchases
Other Great Options
Molekule Air Pro
Commercial-grade with patented PECO technology for destroying pollutants.
Honeywell HPA300
Powerful workhorse for large rooms. Built to last.
RabbitAir MinusA2
Stylish wall-mountable design with customizable artwork panels.
Not sure which air purifier is right for you?
Learn more about different types of air purifiers and how to choose the best one for your needs.
Read our complete buying guide →