Metro area air quality · 2025

Effingham, IL

Median AQI 35 (Good). 95.5% of monitored days rated Good across this metro's EPA monitoring network.

35
Median AQI
95.5%
Good-air days
0
Unhealthy days
95%
Cleaner than US metros

Effingham, IL posted a 2025 median AQI of 35 (Good) with 95.5% Good days

According to the U.S. EPA Air Quality System, the Effingham, IL CBSA recorded a median AQI of 35 across 242 monitored days in 2025, with 95.5% 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 Effingham, IL CBSA's 95.5% Good-day share places it cleaner than 95% of US metros in 2025.
Closest median-AQI peer
Baraboo, WI (75.6% Good, median AQI 35) is the closest nationwide median-AQI peer to Effingham, IL.
2020–2025 Good-day shift
Effingham, IL's Good-day share moved +1.5 points from 2020 to 2025 (median AQI -2).
Median AQI
Median AQI: 35

Aggregated from EPA Air Quality System (2025), 242 monitored days. EPA AQS →

The verdict

Effingham, IL sits in the upper Good-day tercile among EPA CBSA metros on this site (95.5% of 242 monitored days). On the EPA scale the metro runs good, among the cleanest 10% of US metros, with a median AQI of 35 and 95.5% of 242 monitored days in the Good band.

35
median AQI · Good
95.5%
days rated Good
95%
cleaner than US metros
84
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
  • Effingham, IL metro's Good-day share rose from 90.8% to 95.5% between the 2024 and 2025 EPA annual releases, a change of +4.7 percentage points.
  • Effingham, IL metro's median AQI fell from 41 to 35 between the 2024 and 2025 EPA annual releases, a change of -6 points.
  • Effingham, IL metro's peak single-day AQI fell from 101 to 84 between the 2024 and 2025 EPA annual releases, a change of -17 points.

Compared against 239 monitored days in 2024 and 242 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

Effingham, IL sits in the upper Good-day tercile among EPA CBSA metros on this site (95.5% of 242 monitored days). Signature read: 95.5% 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 35 over 242 measured days in 2025 (Good / Excellent). The monitored-day split lands at 231 Good (95%), 11 Moderate (5%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 46; the highest single-day reading hit 84 (Moderate).

Across 2020–2025, Good-day share shifted +1.5 points and median AQI moved -2 (stable). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Baraboo, WI (75.6% good, AQI 35); Ithaca, NY (93.2% good, AQI 35); Kinston, NC (97.5% good, AQI 35).

Best and worst city air quality →

Air Quality Summary

Median AQI

35

Good

Good Days

95.5%

231 of 242 days

Max AQI

84

Moderate

Health Grade

Excellent

90th pct: 46

AQI Day Breakdown (2025)

Distribution of 242 monitored days across EPA AQI categories.

Good

231

95%

Moderate

11

5%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Excellent

The Effingham, IL metro area's air quality is rated Excellent based on 95.5% 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 Effingham, IL metro compare?

How Effingham, IL compares

Good-day share better than typical
Effingham, IL 95.5%
Baraboo, WI 75.6%
Typical US metro 70.6%
Median AQI better than typical
Effingham, IL 35
Baraboo, WI 35
Typical US metro 41
Unhealthy days / yr better than typical
Effingham, IL 0
Baraboo, WI 1
Typical US metro 1

5-Year Air Quality Trend

Air quality is stable in the Effingham, IL metro. Highest Good-day share: 2025 (95.5%, 231 of 242 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 156 10 0 37
2021 226 11 0 37
2022 215 24 0 38
2023 182 50 0 44
2024 217 22 0 41
2025 231 11 0 35

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Effingham, IL (35).

Baraboo, WI

Median AQI 35 · 75.6% Good-day share

35

Ithaca, NY

Median AQI 35 · 93.2% Good-day share

35

Kinston, NC

Median AQI 35 · 97.5% Good-day share

35

Meridian, MS

Median AQI 35 · 94.6% Good-day share

35

Morehead City, NC

Median AQI 35 · 96.2% Good-day share

35

Salem, OR

Median AQI 35 · 80.0% Good-day share

35

Metros with similar unhealthy-day exposure

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

Aberdeen, SD

0 unhealthy-or-worse days · median AQI 27

27

Aberdeen, WA

0 unhealthy-or-worse days · median AQI 22

22

Adrian, MI

0 unhealthy-or-worse days · median AQI 41

41

Akron, OH

0 unhealthy-or-worse days · median AQI 45

45

Albany, GA

0 unhealthy-or-worse days · median AQI 46

46

Albany, OR

0 unhealthy-or-worse days · median AQI 27

27

Frequently Asked Questions

How many unhealthy air days does Effingham, IL have? ▼
In 2025, the Effingham, IL metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 84.
What is the air quality in the Effingham, IL metro area? ▼
The Effingham, IL metro area has a median Air Quality Index (AQI) of 35, rated "Good." 95.5% of monitored days (231 out of 242) had good air quality in 2025.
Is air quality in Effingham, IL getting better or worse? ▼
Air quality in the Effingham, IL metro is stable 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 95.5% (231 of 242 days). Lowest qualifying Good-day share: 2023 at 78.4% (182 of 232 days).
What does AQI 35 mean for health? ▼
An AQI of 35 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 Effingham, IL compare to other metro areas? ▼
The Effingham, IL metro has 95.5% good air days. Similar metros: Baraboo, WI (75.6% good), Ithaca, NY (93.2% good), Kinston, NC (97.5% good).
What is the 90th percentile AQI for Effingham, IL? ▼
The 90th percentile AQI for the Effingham, IL metro area is 46, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 84 (Moderate).

Data Sources

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

Read our methodology , how this data is sourced, computed, and verified.

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