Idaho City, Idaho Air Quality
Idaho City has a median AQI of 43, earning an air quality grade of A- — excellent air quality that ranks better than 39% 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, Idaho City recorded 132 good air quality days (73% of monitored days).
Population: 581 • County: Boise
Current AQI
Quick Facts
| Current AQI | 66 — Moderate |
| Air Quality Grade | A- |
| Median AQI (2025) | 43 |
| vs. U.S. Cities | Better than 39% |
| Primary Pollutant | PM2.5 |
| Unhealthy Days/Year | 0 |
| 10-Year Trend | ↓ Worsening |
| Data Source | EPA AQS (historical) · AirNow (live) |
Health Recommendation
Air quality is acceptable. However, there may be a risk for some people who are unusually sensitive to air pollution.
Unusually sensitive people should consider reducing prolonged or heavy outdoor exertion.
5-Day AQI Forecast
Last 90 Days
Current Pollutant Levels
Real-time data from EPA AirNow
Local Air Quality Context
Air quality data for Idaho City is sourced from the Idaho City monitoring area, located approximately 1 miles from city center. This EPA-certified station continuously tracks particulate matter (PM2.5), the primary driver of air quality alerts in this area.
Wildfire smoke is a significant factor in Idaho City's air quality, with regional fires capable of pushing AQI from Good to Unhealthy within hours during fire season (typically July through October). On smoke-impacted days, staying indoors with windows closed and running an air purifier with a HEPA filter is the most effective protection.
AQI Trend (10 Years)
Air Quality Days by Year
Idaho City Median AQI by Year
Annual EPA air quality data for Idaho City — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 43 | 132 | — | 82 | PM2.5 |
| 2024 | 48 | 189 | 49 | 265 | PM2.5 |
| 2023 | 39 | 250 | — | 98 | PM2.5 |
| 2022 | 39 | 238 | 4 | 188 | PM2.5 |
| 2021 | 49 | 186 | 12 | 161 | PM2.5 |
| 2020 | 46 | 199 | 12 | 223 | PM2.5 |
| 2019 | 44 | 223 | 3 | 170 | PM2.5 |
| 2018 | 52 | 169 | 6 | 130 | PM2.5 |
| 2017 | 46 | 209 | 10 | 268 | PM2.5 |
| 2016 | 38 | 251 | 6 | 157 | 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 Idaho City Air Quality
What is the air quality in Idaho City today?
The current AQI in Idaho City is 66, rated "Moderate". Air quality is moderate — unusually sensitive individuals may want to limit prolonged outdoor exertion. Air quality is acceptable. However, there may be a risk for some people who are unusually sensitive to air pollution.
Is air quality in Idaho City getting better or worse?
Air quality in Idaho City has been worsening. The median AQI has risen 5 points (from 38 in 2016 to 43 in 2025), a concern for local health officials.
What is the most common air pollutant in Idaho City?
PM2.5 is the primary air pollutant in Idaho City, responsible for 181 days (100% of monitored days) in 2025. Particulate matter originates from vehicle exhaust, wildfires, construction, and industrial activity.
How many unhealthy air days does Idaho City have per year?
In 2025, Idaho City recorded 73% good air quality days (132 days) out of 181 monitored days. There were 0 Unhealthy for Sensitive Groups days and 0 Unhealthy days (AQI above 100). The highest single-day AQI recorded was 82.
What air quality grade does Idaho City receive?
Idaho City receives an air quality grade of A-, placing it better than 39% of US cities. This is based on a median AQI of 43 in 2025, with 132 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 39% of US cities
Nearby Cities
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National Rankings
See how Idaho City compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Idaho City
Idaho City faces elevated PM2.5 from wildfire smoke in addition to year-round traffic and industrial sources. We prioritize True HEPA units with high smoke CADR — essential for rapid air cleaning during smoke events.
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