Grafton, Wisconsin Air Quality
Grafton has a median AQI of 35, earning an air quality grade of A — excellent air quality that ranks better than 82% 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, Grafton recorded 146 good air quality days (81% of monitored days) and 4 unhealthy days.
Population: 12,445 • County: Ozaukee
Current AQI
Quick Facts
| Current AQI | 13 — Good |
| Air Quality Grade | A |
| Median AQI (2025) | 35 |
| vs. U.S. Cities | Better than 82% |
| Primary Pollutant | PM2.5 |
| Unhealthy Days/Year | 4 |
| 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 Grafton is sourced from the Harrington Beach monitoring area, located approximately 14 miles from city center. This EPA-certified station continuously tracks particulate matter (PM2.5), the primary driver of air quality alerts in this area.
Grafton has relatively consistent air quality throughout the year without a strong seasonal peak. Air quality is primarily influenced by local traffic, industrial activity, and regional weather patterns rather than a single seasonal driver.
AQI Trend (10 Years)
Air Quality Days by Year
Grafton Median AQI by Year
Annual EPA air quality data for Grafton — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 35 | 146 | 4 | 140 | PM2.5 |
| 2024 | 37 | 296 | 9 | 161 | Ozone |
| 2023 | 45 | 219 | 18 | 210 | PM2.5 |
| 2022 | 41 | 228 | 5 | 159 | Ozone |
| 2021 | 43 | 241 | 7 | 129 | PM2.5 |
| 2020 | 40 | 269 | 5 | 164 | PM2.5 |
| 2019 | 40 | 271 | 3 | 108 | PM2.5 |
| 2018 | 43 | 254 | 7 | 169 | Ozone |
| 2017 | 40 | 276 | 8 | 136 | Ozone |
| 2016 | 38 | 269 | 9 | 172 | 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 Grafton Air Quality
What is the air quality in Grafton today?
The current AQI in Grafton is 13, 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 Grafton getting better or worse?
Air quality in Grafton has been stable. The median AQI has dropped 3 points (from 38 in 2016 to 35 in 2025).
What is the most common air pollutant in Grafton?
PM2.5 is the primary air pollutant in Grafton, responsible for 110 days (61% of monitored days) in 2025. Particulate matter originates from vehicle exhaust, wildfires, construction, and industrial activity.
How many unhealthy air days does Grafton have per year?
In 2025, Grafton recorded 81% good air quality days (146 days) out of 181 monitored days. There were 4 Unhealthy for Sensitive Groups days and 0 Unhealthy days (AQI above 100). The highest single-day AQI recorded was 140.
What air quality grade does Grafton receive?
Grafton receives an air quality grade of A, placing it better than 82% of US cities. This is based on a median AQI of 35 in 2025, with 146 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 82% of US cities
Nearby Cities
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National Rankings
See how Grafton compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Grafton
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