North Westminster, Vermont Air Quality
North Westminster has a median AQI of 12, earning an air quality grade of A+ — excellent air quality that ranks better than 97% 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, North Westminster recorded 20 good air quality days (100% of monitored days).
Population: 125 • County: Windham
Current AQI
Quick Facts
| Current AQI | 12 — Good |
| Air Quality Grade | A+ |
| Median AQI (2025) | 12 |
| vs. U.S. Cities | Better than 97% |
| 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 North Westminster is sourced from the Keene monitoring area, located approximately 16 miles from city center. This EPA-certified station continuously tracks particulate matter (PM2.5), the primary driver of air quality alerts in this area.
North Westminster 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
North Westminster Median AQI by Year
Annual EPA air quality data for North Westminster — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 12 | 20 | — | 46 | PM2.5 |
| 2024 | 12 | 116 | — | 69 | PM2.5 |
| 2023 | 14 | 112 | — | 95 | PM2.5 |
| 2022 | 11 | 71 | — | 44 | PM2.5 |
| 2021 | 11 | 114 | — | 56 | PM2.5 |
| 2020 | 12 | 113 | — | 42 | PM2.5 |
| 2019 | 11 | 103 | — | 52 | PM2.5 |
| 2018 | 12 | 112 | — | 57 | PM2.5 |
| 2017 | 14 | 115 | — | 54 | PM2.5 |
| 2016 | 13 | 105 | — | 58 | 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 North Westminster Air Quality
What is the air quality in North Westminster today?
The current AQI in North Westminster is 12, 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 North Westminster getting better or worse?
Air quality in North Westminster has been stable. The median AQI has dropped 1 points (from 13 in 2016 to 12 in 2025).
What is the most common air pollutant in North Westminster?
PM2.5 is the primary air pollutant in North Westminster, responsible for 20 days (100% of monitored days) in 2025. Particulate matter originates from vehicle exhaust, wildfires, construction, and industrial activity.
How many unhealthy air days does North Westminster have per year?
In 2025, North Westminster recorded 100% good air quality days (20 days) out of 20 monitored days. There were 0 Unhealthy for Sensitive Groups days and 0 Unhealthy days (AQI above 100). The highest single-day AQI recorded was 46.
What air quality grade does North Westminster receive?
North Westminster receives an air quality grade of A+, placing it better than 97% of US cities. This is based on a median AQI of 12 in 2025, with 20 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 97% of US cities
Nearby Cities
Get AQI Alerts
Receive notifications when air quality changes in North Westminster
National Rankings
See how North Westminster compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for North Westminster
North Westminster 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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