Henry, South Dakota Air Quality
Henry has a median AQI of 33, earning an air quality grade of A — excellent air quality that ranks better than 85% of US cities. Air quality has been trending worse over the past decade, a concern for local residents and health officials. Particulate matter (PM2.5) is the primary concern, often linked to vehicle traffic, industrial activity, and wildfire smoke. In 2025, Henry recorded 147 good air quality days (82% of monitored days) and 2 unhealthy days.
Population: 237 • County: Codington
Current AQI
Quick Facts
| Current AQI | 24 — Good |
| Air Quality Grade | A |
| Median AQI (2025) | 33 |
| vs. U.S. Cities | Better than 85% |
| Primary Pollutant | PM2.5 |
| Unhealthy Days/Year | 2 |
| 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 Henry is sourced from the Research Farm monitoring area, located approximately 49 miles from city center. This EPA-certified station continuously tracks particulate matter (PM2.5), the primary driver of air quality alerts in this area.
Henry 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
Henry Median AQI by Year
Annual EPA air quality data for Henry — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 33 | 147 | 2 | 154 | PM2.5 |
| 2024 | 37 | 269 | 1 | 102 | PM2.5 |
| 2023 | 45 | 215 | 13 | 164 | PM2.5 |
| 2022 | 41 | 285 | 1 | 101 | Ozone |
| 2021 | 43 | 246 | 6 | 271 | PM2.5 |
| 2020 | 38 | 293 | 1 | 101 | PM2.5 |
| 2019 | 32 | 295 | — | 83 | PM2.5 |
| 2018 | 39 | 260 | 1 | 103 | PM2.5 |
| 2017 | 39 | 276 | — | 82 | PM2.5 |
| 2016 | 28 | 295 | — | 73 | 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 Henry Air Quality
What is the air quality in Henry today?
The current AQI in Henry is 24, 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 Henry getting better or worse?
Air quality in Henry has been worsening. The median AQI has risen 5 points (from 28 in 2016 to 33 in 2025), a concern for local health officials.
What is the most common air pollutant in Henry?
PM2.5 is the primary air pollutant in Henry, responsible for 92 days (51% of monitored days) in 2025. Particulate matter originates from vehicle exhaust, wildfires, construction, and industrial activity.
How many unhealthy air days does Henry have per year?
In 2025, Henry recorded 82% good air quality days (147 days) out of 179 monitored days. There were 1 Unhealthy for Sensitive Groups days and 1 Unhealthy days (AQI above 100). The highest single-day AQI recorded was 154.
What air quality grade does Henry receive?
Henry receives an air quality grade of A, placing it better than 85% of US cities. This is based on a median AQI of 33 in 2025, with 147 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 85% of US cities
Nearby Cities
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National Rankings
See how Henry compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Henry
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