Metro area air quality · 2025

Moscow, ID

Median AQI 31 (Good). 83.4% of monitored days rated Good across this metro's EPA monitoring network.

31
Median AQI
83.4%
Good-air days
0
Unhealthy days
74%
Cleaner than US metros

Moscow, ID posted a 2025 median AQI of 31 (Good) with 83.4% Good days

According to the U.S. EPA Air Quality System, the Moscow, ID CBSA recorded a median AQI of 31 across 338 monitored days in 2025, with 83.4% 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 Moscow, ID CBSA's 83.4% Good-day share places it cleaner than 74% of US metros in 2025.
Closest median-AQI peer
Athens, OH (83.4% Good, median AQI 31) is the closest nationwide median-AQI peer to Moscow, ID.
2020–2025 Good-day shift
Moscow, ID's Good-day share moved -6.2 points from 2020 to 2025 (median AQI +10).
Median AQI
Median AQI: 31

Aggregated from EPA Air Quality System (2025), 338 monitored days. EPA AQS →

The verdict

Moscow, ID sits in the upper Good-day tercile among EPA CBSA metros on this site (83.4% of 338 monitored days). On the EPA scale the metro runs good, cleaner than the median US metro, with a median AQI of 31 and 83.4% of 338 monitored days in the Good band.

31
median AQI · Good
83.4%
days rated Good
74%
cleaner than US metros
107
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
  • Moscow, ID metro's Good-day share rose from 81.4% to 83.7% between the 2024 and 2025 EPA annual releases, a change of +2.3 percentage points.
  • Moscow, ID metro's median AQI rose from 27 to 31 between the 2024 and 2025 EPA annual releases, a change of +4 points.
  • Moscow, ID metro's peak single-day AQI fell from 117 to 107 between the 2024 and 2025 EPA annual releases, a change of -10 points.

Compared against 365 monitored days in 2024 and 337 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

Moscow, ID sits in the upper Good-day tercile among EPA CBSA metros on this site (83.4% of 338 monitored days). Signature read: 83.4% 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 31 over 338 measured days in 2025 (Good / Good). The monitored-day split lands at 282 Good (83%), 55 Moderate (16%), and 1 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 57; the highest single-day reading hit 107 (USG).

Across 2020–2025, Good-day share shifted -6.2 points and median AQI moved +10 (worsening). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Athens, OH (83.4% good, AQI 31); Bellingham, WA (94.0% good, AQI 31); Clearlake, CA (99.2% good, AQI 31).

Best and worst city air quality →

Air Quality Summary

Median AQI

31

Good

Good Days

83.4%

282 of 338 days

Max AQI

107

USG

Health Grade

Good

90th pct: 57

AQI Day Breakdown (2025)

Distribution of 338 monitored days across EPA AQI categories.

Good

282

83%

Moderate

55

16%

USG

1

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Good

The Moscow, ID metro area's air quality is rated Good based on 83.4% 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 Moscow, ID metro compare?

How Moscow, ID compares

Good-day share better than typical
Moscow, ID 83.4%
Athens, OH 83.4%
Typical US metro 70.6%
Median AQI better than typical
Moscow, ID 31
Athens, OH 31
Typical US metro 41
Unhealthy days / yr better than typical
Moscow, ID 0
Athens, OH 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is worsening in the Moscow, ID metro. Highest Good-day share: 2020 (89.9%, 319 of 355 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 319 35 1 21
2021 309 41 5 20
2022 312 44 4 13
2023 320 38 1 22
2024 297 68 0 27
2025 282 55 0 31

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Moscow, ID (31).

Metros with similar unhealthy-day exposure

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

Frequently Asked Questions

How many unhealthy air days does Moscow, ID have?
In 2025, the Moscow, ID metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 107.
What is the air quality in the Moscow, ID metro area?
The Moscow, ID metro area has a median Air Quality Index (AQI) of 31, rated "Good." 83.4% of monitored days (282 out of 338) had good air quality in 2025.
Is air quality in Moscow, ID getting better or worse?
Air quality in the Moscow, ID metro is worsening across floor-qualifying years (2020-2025); years with fewer than 100 monitored days are excluded from that direction. Highest qualifying Good-day share: 2020 at 89.9% (319 of 355 days). Lowest qualifying Good-day share: 2024 at 81.4% (297 of 365 days).
What does AQI 31 mean for health?
An AQI of 31 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 Moscow, ID compare to other metro areas?
The Moscow, ID metro has 83.4% good air days. Similar metros: Athens, OH (83.4% good), Bellingham, WA (94.0% good), Clearlake, CA (99.2% good).
What is the 90th percentile AQI for Moscow, ID?
The 90th percentile AQI for the Moscow, ID metro area is 57, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 107 (USG).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Moscow, 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, Moscow, ID · 2020–2025