Union, South Dakota Air Quality
Union County, South Dakota (SD)
→ Stableover 8 years
10-Year AQI Trend
The solid line shows the median AQI each year. The dashed line shows the 90th percentile (worst 10% of days).
Air Quality Day Breakdown
Number of days per year in each EPA AQI category. Green = Good (AQI 0-50), Yellow = Moderate (51-100), Orange = Unhealthy for Sensitive Groups (101-150), Red = Unhealthy or worse (151+).
Year-by-Year Data
| Year | Median AQI | 90th Pct | Max AQI | Good Days | Moderate | Unhealthy+ | Pollutant |
|---|---|---|---|---|---|---|---|
| 2021 | 44 | 64 | 167 | 179 | 90 | 4 | Ozone |
| 2020 | 39 | 56 | 141 | 304 | 61 | 1 | Ozone |
| 2019 | 37 | 56 | 97 | 306 | 58 | 0 | Ozone |
| 2018 | 43 | 62 | 112 | 256 | 106 | 3 | Ozone |
| 2017 | 41 | 58 | 100 | 278 | 87 | 0 | Ozone |
| 2016 | 38 | 57 | 112 | 295 | 69 | 2 | Ozone |
| 2015 | 43 | 61 | 108 | 243 | 120 | 2 | PM2.5 |
| 2014 | 43 | 61 | 100 | 244 | 121 | 0 | PM2.5 |
What This Means for Union County Residents
Union, South Dakota has received an Air Quality Grade of B (67/100) based on a decade of monitoring data from the EPA's air quality monitoring program. The current median AQI of 44 falls in the "Good" range.
The primary pollutant affecting this area is Ground-Level Ozone. Over the past 5 years, this area has averaged 2 unhealthy air quality days per year — days when sensitive groups (children, elderly, those with respiratory conditions) should limit outdoor activity. The American Lung Association's State of the Air report provides additional context on long-term health risks from air pollution exposure.
Related Cities in South Dakota
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AQI: 45 · Grade: D
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AQI: 43 · Grade: C
AQI: 44 · Grade: B
Frequently Asked Questions
Union, South Dakota has a current median AQI of 44, which falls in the "Good" range. The area has received an Air Quality Grade of B (67/100) based on 10 years of EPA monitoring data.
Air quality in Union, South Dakota is stable over the past decade. The median AQI has changed by +1 points from 2014 to 2021.
Union, South Dakota averages 2 unhealthy air quality days per year over the past 5 years. On these days, sensitive groups including children, the elderly, and those with respiratory conditions should limit outdoor activity.
The primary pollutant affecting Union, South Dakota is Ground-Level Ozone. This is the dominant contributor to elevated AQI readings in the Union County area.
Union, South Dakota averages 2 unhealthy air days per year. This is relatively low, making it a reasonable choice for asthma sufferers. The primary pollutant is Ground-Level Ozone, which is a known asthma trigger.
With a median AQI of 44 (Good), outdoor exercise in Union, South Dakota is generally safe year-round. Union, South Dakota averages 2 days per year when athletes should move workouts indoors.