Metro area air quality · 2025

Idaho Falls, ID

Median AQI 43 (Good). 85.2% of monitored days rated Good across this metro's EPA monitoring network.

43
Median AQI
85.2%
Good-air days
0
Unhealthy days
78%
Cleaner than US metros

Idaho Falls, ID posted a 2025 median AQI of 43 (Good) with 85.2% Good days

According to the U.S. EPA Air Quality System, the Idaho Falls, ID CBSA recorded a median AQI of 43 across 365 monitored days in 2025, with 85.2% rated Good and 0 unhealthy or worse. This is an annual metro comparison, not a live advisory.

Data source EPA Air Quality System (AQS)

Cleaner than US metros
The Idaho Falls, ID CBSA's 85.2% Good-day share places it cleaner than 78% of US metros in 2025.
Closest median-AQI peer
Ashtabula, OH (81.2% Good, median AQI 43) is the closest nationwide median-AQI peer to Idaho Falls, ID.
2020–2025 Good-day shift
Idaho Falls, ID's Good-day share moved +5.5 points from 2020 to 2025 (median AQI +2).
Median AQI
Median AQI: 43

Aggregated from EPA Air Quality System (2025), 365 monitored days. EPA AQS →

The verdict

Idaho Falls, ID sits in the upper Good-day tercile among EPA CBSA metros on this site (85.2% of 365 monitored days). On the EPA scale the metro runs good, cleaner than most US metros, with a median AQI of 43 and 85.2% of 365 monitored days in the Good band.

43
median AQI · Good
85.2%
days rated Good
78%
cleaner than US metros
95
worst single reading

No day crossed into the Unhealthy tier across the metro's monitors in 2025.

Annual release change

What changed in the 2025 EPA annual release

2024 → 2025
  • Idaho Falls, ID metro's Good-day share rose from 79.5% to 85.2% between the 2024 and 2025 EPA annual releases, a change of +5.7 percentage points.

Compared against 366 monitored days in 2024 and 365 in 2025. These are arithmetic differences between two stored EPA annual summaries, not a cause claim or a live advisory.

National release changes Two-year CSV

Idaho Falls, ID sits in the upper Good-day tercile among EPA CBSA metros on this site (85.2% of 365 monitored days). Signature read: 85.2% Good-day share (high tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 43 over 365 measured days in 2025 (Good / Good). The monitored-day split lands at 311 Good (85%), 54 Moderate (15%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 54; the highest single-day reading hit 95 (Moderate).

Across 2020–2025, Good-day share shifted +5.5 points and median AQI moved +2 (improving). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Ashtabula, OH (81.2% good, AQI 43); Bloomington, IN (67.7% good, AQI 43); Champaign-Urbana, IL (65.8% good, AQI 43).

Best and worst city air quality →

Air Quality Summary

Median AQI

43

Good

Good Days

85.2%

311 of 365 days

Max AQI

95

Moderate

Health Grade

Good

90th pct: 54

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

311

85%

Moderate

54

15%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Good

The Idaho Falls, ID metro area's air quality is rated Good based on 85.2% good air days. No unhealthy air days were recorded in 2025.

Air quality is generally acceptable. Unusually sensitive people should monitor real-time conditions at AirNow.gov during high-pollution events.

How does the Idaho Falls, ID metro compare?

How Idaho Falls, ID compares

Good-day share better than typical
Idaho Falls, ID 85.2%
Ashtabula, OH 81.2%
Typical US metro 70.6%
Median AQI worse than typical
Idaho Falls, ID 43
Ashtabula, OH 43
Typical US metro 41
Unhealthy days / yr better than typical
Idaho Falls, ID 0
Ashtabula, OH 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is improving in the Idaho Falls, ID metro. Highest Good-day share: 2025 (85.2%, 311 of 365 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 291 70 4 41
2021 265 90 0 44
2022 297 67 0 43
2023 306 59 0 44
2024 291 75 0 43
2025 311 54 0 43

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Idaho Falls, ID (43).

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Idaho Falls, ID's 0 (independent of median AQI).

Frequently Asked Questions

How many unhealthy air days does Idaho Falls, ID have?
In 2025, the Idaho Falls, ID metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 95.
What is the air quality in the Idaho Falls, ID metro area?
The Idaho Falls, ID metro area has a median Air Quality Index (AQI) of 43, rated "Good." 85.2% of monitored days (311 out of 365) had good air quality in 2025.
Is air quality in Idaho Falls, ID getting better or worse?
Air quality in the Idaho Falls, ID metro is improving across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2025 at 85.2% (311 of 365 days). Lowest qualifying Good-day share: 2021 at 74.6% (265 of 355 days).
What does AQI 43 mean for health?
An AQI of 43 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
How does Idaho Falls, ID compare to other metro areas?
The Idaho Falls, ID metro has 85.2% good air days. Similar metros: Ashtabula, OH (81.2% good), Bloomington, IN (67.7% good), Champaign-Urbana, IL (65.8% good).
What is the 90th percentile AQI for Idaho Falls, ID?
The 90th percentile AQI for the Idaho Falls, ID metro area is 54, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 95 (Moderate).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Idaho Falls, ID, 2025. See our methodology for how AQI, median, and coverage figures are computed.

Source: U.S. EPA Air Quality System (AQS) Annual AQI by CBSA summary, Idaho Falls, ID · 2020–2025