Median AQI
37
Good
Idaho · County air quality · 2025
Shoshone County, Idaho
Median AQI 37 (Good). 65.7% of monitored days rated Good, direct from EPA Air Quality System stations.
- 37
- Median AQI
- 65.7%
- Good-air days
- 0
- Unhealthy days
- 24%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Shoshone County's air is good on balance, among the more polluted 10% of US counties, a median AQI of 37 with 65.7% of 210 monitored days in the Good band, driven mainly by PM2.5.
- 37
- median AQI · Good
- 65.7%
- days rated Good
- PM2.5
- main pollutant
- 24%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 111.
Data updated July 2026
- Good · 138 d · 65.7%
- Moderate · 71 d · 33.8%
- USG · 1 d · 0.5%
How did Shoshone County's air break down in 2025?
Across 210 monitored days, 138 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 111 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 210 days monitored. Median AQI: 37 (Good).
Insights: Shoshone County, Idaho. EPA monitors recorded a median Air Quality Index of 37 across 210 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 138 (66%) fell in the Good band (AQI 0–50), 71 (34%) registered Moderate readings, and 1 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 66, while the worst single-day peak hit 111 (USG). Residents averaged about 19.7 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (209 days), PM10 (1 days). Across the 2020–2025 trend window, good days shifted by -83 and the median AQI moved -4 points, placing the multi-year trajectory at improving. The worst single reading over the 2020–2025 window was AQI 111, usg but never Unhealthy. Nearby counties show comparable readings: Ada (80.6% good, AQI 39); Bannock (91.5% good, AQI 31); Benewah (74.6% good, AQI 37); Blaine (99.4% good, AQI 22); Boise (72.9% good, AQI 43); Bonner (71.3% good, AQI 41).
Air Quality Summary
Good Days
65.7%
138 of 210 monitored days
-9.3pp vs 75% target
Max AQI Recorded
111
USG
Health Grade
Moderate
90th-pct AQI 66
Shoshone County, Good days share 65.7%
National avg
Share of monitored days at AQI 0-50 (Good band).
Shoshone County, Unhealthy-or-worse share 0.0%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 210 monitored days across EPA AQI categories.
Good
138
66%
Moderate
71
34%
USG
1
0%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Shoshone County.
- PM2.5 · 209 days · 99.5%
- PM10 · 1 days · 0.5%
Health Impact Assessment
Moderate
Shoshone County's air quality is rated Moderate based on 65.7% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 65.7% of monitored days in 2025, with a median AQI of 37. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 209 of 210 monitored days.
5-Year Air Quality Trend
Air quality is improving in Shoshone County. Best year: 2020 (221 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 221 | 138 | 0 | 3 | 41 | 440 |
| 2021 | 186 | 162 | 9 | 6 | 49 | 179 |
| 2022 | 217 | 141 | 4 | 3 | 42 | 172 |
| 2023 | 197 | 162 | 3 | 3 | 47 | 160 |
| 2024 | 209 | 156 | 1 | 0 | 46 | 112 |
| 2025 | 138 | 71 | 1 | 0 | 37 | 111 |
How does Shoshone County compare?
How Shoshone County compares
Good-day share worse than US avg
Shoshone County 65.7%
Ada County, Idaho 80.6%
US average 76.5%
Median AQI better than US avg
Shoshone County 37
Ada County, Idaho 39
US average 38
Unhealthy days / yr about average
Shoshone County 0
Ada County, Idaho 0
US average 0
Other Counties in Idaho
Air quality comparison for nearby counties in Idaho.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Shoshone County.
Alachua County, Florida
AQI 37 · 90.1% good
Beltrami County, Minnesota
AQI 37 · 88.8% good
Benewah County, Idaho
AQI 37 · 74.6% good
Brevard County, Florida
AQI 37 · 89.7% good
Brown County, Indiana
AQI 37 · 94.5% good
Brown County, Wisconsin
AQI 37 · 79.0% good
What Shoshone County's air means for you
The air here stays in the breathable range year-round, with PM2.5 the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-PM2.5 days, the guide explains what a median of 37 means for exposure. Health guidance
- See how Shoshone County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Shoshone County with its Idaho neighbours before drawing a conclusion about the region. All of Idaho
Based on 210 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
More Air Quality Data
Air Quality Guides
Frequently Asked Questions
What is the air quality in Shoshone County, Idaho? ▼
Shoshone County has a median Air Quality Index (AQI) of 37, rated "Good." 65.7% of monitored days (138 out of 210) had good air quality in 2025.
What is the main pollutant in Shoshone County? ▼
The primary pollutant in Shoshone County is Fine Particles (PM2.5), which was the main AQI driver on 209 days (100% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Shoshone County have? ▼
In 2025, Shoshone County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 111.
Is the air quality in Shoshone County getting better or worse? ▼
Air quality in Shoshone County is improving based on 5-year trends (2020-2025). Best year: 2020 with 221 good days. Worst year: 2025 with 138 good days.
What does AQI 37 mean for health? ▼
Shoshone County's median AQI of 37 falls in the "Good" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Shoshone County compare to other counties in Idaho? ▼
Shoshone County has 65.7% good air days. Nearby counties in Idaho: Ada (80.6% good), Bannock (91.5% good), Benewah (74.6% good), Blaine (99.4% good), Boise (72.9% good), Bonner (71.3% good).
What is the 90th percentile AQI in Shoshone County? ▼
The 90th percentile AQI for Shoshone County is 66, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 111 (USG).
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer.
Every figure on PlainAir is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.