Median AQI
41
Good
Idaho · County air quality · 2025
Bonner County, Idaho
Median AQI 41 (Good). 71.3% of monitored days rated Good, direct from EPA Air Quality System stations.
- 41
- Median AQI
- 71.3%
- Good-air days
- 0
- Unhealthy days
- 34%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Bonner County's air is good on balance, more polluted than the median US county, a median AQI of 41 with 71.3% of 181 monitored days in the Good band, driven mainly by PM2.5.
- 41
- median AQI · Good
- 71.3%
- days rated Good
- PM2.5
- main pollutant
- 34%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 74.
Data updated July 2026
- Good · 129 d · 71.3%
- Moderate · 52 d · 28.7%
How did Bonner County's air break down in 2025?
Across 181 monitored days, 129 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 74 (Moderate).
EPA AQS →Air quality data from EPA Air Quality System (2025). 181 days monitored. Median AQI: 41 (Good).
Insights: Bonner County, Idaho. EPA monitors recorded a median Air Quality Index of 41 across 181 measured days in 2025, earning a Good classification and a Moderate health grade. Of those days, 129 (71%) fell in the Good band (AQI 0–50), 52 (29%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 56, while the worst single-day peak hit 74 (Moderate). Residents averaged about 21.4 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (178 days), PM10 (3 days). Across the 2020–2025 trend window, good days shifted by -154 and the median AQI moved +9 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 74, moderate 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); Bonneville (94.9% good, AQI 19).
Air Quality Summary
Good Days
71.3%
129 of 181 monitored days
-3.7pp vs 75% target
Max AQI Recorded
74
Moderate
Health Grade
Moderate
90th-pct AQI 56
Bonner County, Good days share 71.3%
National avg
Share of monitored days at AQI 0-50 (Good band).
Bonner 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 181 monitored days across EPA AQI categories.
Good
129
71%
Moderate
52
29%
USG
0
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 Bonner County.
- PM2.5 · 178 days · 98.3%
- PM10 · 3 days · 1.7%
Health Impact Assessment
Moderate
Bonner County's air quality is rated Moderate based on 71.3% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 71.3% of monitored days in 2025, with a median AQI of 41. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 178 of 181 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Bonner County. Best year: 2020 (283 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 283 | 72 | 5 | 5 | 32 | 190 |
| 2021 | 260 | 94 | 4 | 4 | 37 | 203 |
| 2022 | 259 | 97 | 5 | 2 | 35 | 216 |
| 2023 | 273 | 86 | 2 | 1 | 34 | 261 |
| 2024 | 272 | 89 | 4 | 0 | 32 | 125 |
| 2025 | 129 | 52 | 0 | 0 | 41 | 74 |
How does Bonner County compare?
How Bonner County compares
Good-day share worse than US avg
Bonner County 71.3%
Ada County, Idaho 80.6%
US average 76.5%
Median AQI worse than US avg
Bonner County 41
Ada County, Idaho 39
US average 38
Unhealthy days / yr about average
Bonner 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 Bonner County.
Albemarle County, Virginia
AQI 41 · 77.9% good
Anderson County, South Carolina
AQI 41 · 90.0% good
Berkshire County, Massachusetts
AQI 41 · 71.6% good
Berrien County, Michigan
AQI 41 · 80.9% good
Blair County, Pennsylvania
AQI 41 · 71.9% good
Boone County, Missouri
AQI 41 · 89.1% good
What Bonner 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 41 means for exposure. Health guidance
- See how Bonner County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Bonner County with its Idaho neighbours before drawing a conclusion about the region. All of Idaho
Based on 181 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 Bonner County, Idaho? ▼
Bonner County has a median Air Quality Index (AQI) of 41, rated "Good." 71.3% of monitored days (129 out of 181) had good air quality in 2025.
What is the main pollutant in Bonner County? ▼
The primary pollutant in Bonner County is Fine Particles (PM2.5), which was the main AQI driver on 178 days (98% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Bonner County have? ▼
In 2025, Bonner County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 74.
Is the air quality in Bonner County getting better or worse? ▼
Air quality in Bonner County is worsening based on 5-year trends (2020-2025). Best year: 2020 with 283 good days. Worst year: 2025 with 129 good days.
What does AQI 41 mean for health? ▼
Bonner County's median AQI of 41 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 Bonner County compare to other counties in Idaho? ▼
Bonner County has 71.3% 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), Bonneville (94.9% good).
What is the 90th percentile AQI in Bonner County? ▼
The 90th percentile AQI for Bonner County is 56, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 74 (Moderate).
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.