Metro area air quality · 2025

New Castle, IN

Median AQI 37 (Good). 69.9% of monitored days rated Good across this metro's EPA monitoring network.

37
Median AQI
69.9%
Good-air days
0
Unhealthy days
45%
Cleaner than US metros

New Castle, IN posted a 2025 median AQI of 37 (Good) with 69.9% Good days

According to the U.S. EPA Air Quality System, the New Castle, IN CBSA recorded a median AQI of 37 across 365 monitored days in 2025, with 69.9% 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 New Castle, IN CBSA's 69.9% Good-day share places it cleaner than 45% of US metros in 2025.
Closest median-AQI peer
Alexandria, LA (73.7% Good, median AQI 37) is the closest nationwide median-AQI peer to New Castle, IN.
2020–2025 Good-day shift
New Castle, IN's Good-day share moved -3.9 points from 2020 to 2025 (median AQI -2).
Median AQI
Median AQI: 37

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

The verdict

New Castle, IN's median AQI 37 is in the lower (cleaner) CBSA tercile on this site. On the EPA scale the metro runs good, more polluted than the median US metro, with a median AQI of 37 and 69.9% of 365 monitored days in the Good band.

37
median AQI · Good
69.9%
days rated Good
45%
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
  • New Castle, IN metro's Good-day share fell from 78.1% to 69.9% between the 2024 and 2025 EPA annual releases, a change of -8.3 percentage points.
  • New Castle, IN metro's peak single-day AQI rose from 75 to 95 between the 2024 and 2025 EPA annual releases, a change of +20 points.
  • New Castle, IN metro's median AQI rose from 34 to 37 between the 2024 and 2025 EPA annual releases, a change of +3 points.

Compared against 361 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

New Castle, IN's median AQI 37 is in the lower (cleaner) CBSA tercile on this site. Signature read: median AQI 37 (low tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 37 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 255 Good (70%), 110 Moderate (30%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 59; the highest single-day reading hit 95 (Moderate).

Across 2020–2025, Good-day share shifted -3.9 points and median AQI moved -2 (worsening). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Alexandria, LA (73.7% good, AQI 37); Athens, TN (78.2% good, AQI 37); Bennington, VT (83.6% good, AQI 37).

Understanding AQI →

Air Quality Summary

Median AQI

37

Good

Good Days

69.9%

255 of 365 days

Max AQI

95

Moderate

Health Grade

Moderate

90th pct: 59

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

255

70%

Moderate

110

30%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Moderate

The New Castle, IN metro area's air quality is rated Moderate based on 69.9% 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 New Castle, IN metro compare?

How New Castle, IN compares

Good-day share worse than typical
New Castle, IN 69.9%
Alexandria, LA 73.7%
Typical US metro 70.6%
Median AQI better than typical
New Castle, IN 37
Alexandria, LA 37
Typical US metro 41
Unhealthy days / yr better than typical
New Castle, IN 0
Alexandria, LA 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is worsening in the New Castle, IN metro. Highest Good-day share: 2022 (78.4%, 87 of 111 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 87 31 0 39
2021 78 39 0 38
2022 87 24 0 34
2023 214 124 2 44
2024 282 79 0 34
2025 255 110 0 37

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near New Castle, IN (37).

Alexandria, LA

Median AQI 37 · 73.7% Good-day share

37

Athens, TN

Median AQI 37 · 78.2% Good-day share

37

Bennington, VT

Median AQI 37 · 83.6% Good-day share

37

Blacksburg-Christiansburg-Radford, VA

Median AQI 37 · 94.4% Good-day share

37

Cadillac, MI

Median AQI 37 · 86.0% Good-day share

37

Chambersburg-Waynesboro, PA

Median AQI 37 · 91.5% Good-day share

37

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to New Castle, IN'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

What does AQI 37 mean for health? ▼
An AQI of 37 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 many unhealthy air days does New Castle, IN have? ▼
In 2025, the New Castle, IN 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 New Castle, IN metro area? ▼
The New Castle, IN metro area has a median Air Quality Index (AQI) of 37, rated "Good." 69.9% of monitored days (255 out of 365) had good air quality in 2025.
Is air quality in New Castle, IN getting better or worse? ▼
Air quality in the New Castle, IN 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: 2022 at 78.4% (87 of 111 days). Lowest qualifying Good-day share: 2023 at 62.9% (214 of 340 days).
How does New Castle, IN compare to other metro areas? ▼
The New Castle, IN metro has 69.9% good air days. Similar metros: Alexandria, LA (73.7% good), Athens, TN (78.2% good), Bennington, VT (83.6% good).
What is the 90th percentile AQI for New Castle, IN? ▼
The 90th percentile AQI for the New Castle, IN metro area is 59, 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 New Castle, IN, 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, New Castle, IN · 2020–2025