Metro area air quality · 2024

New Castle, IN

Median AQI 34 (Good). 78.1% of monitored days rated Good across this metro's EPA monitoring network.

34
Median AQI
78.1%
Good-air days
0
Unhealthy days
60%
Cleaner than US metros

Aggregated from EPA Air Quality System (2024), 361 monitored days. EPA AQS → · NOAA →

Insights: New Castle, IN metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 34 over 361 measured days in 2024, which corresponds to a Good band and a Good metro-wide health grade. The monitored-day split lands at 282 Good days (78%), 79 Moderate (22%), and 0 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 55 while the highest single-day reading hit 75 (Moderate). Metro residents averaged roughly 23.4 clean-air days per 30-day window across the reporting year.

Across the 2020–2024 trend window, good days shifted by +195 and the median AQI moved -5 points, which classifies the multi-year trajectory as improving. The metro avoided any Unhealthy-tier days entirely, an outcome that typically reflects favorable wind patterns, lower industrial density, or effective regional emission controls. Metros with comparable AQI profiles include Clarksburg, WV (80.5% good, AQI 34); Kinston, NC (95.8% good, AQI 34); Sioux Falls, SD (81.4% good, AQI 34).

Air Quality Summary

Median AQI

34

Good

Good Days

78.1%

282 of 361 days

Max AQI

75

Moderate

Health Grade

Good

90th pct: 55

AQI Day Breakdown (2024)

Distribution of 361 monitored days across EPA AQI categories.

Good

282

78%

Moderate

79

22%

USG

0

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Good

The New Castle, IN metro area's air quality is rated Good based on 78.1% good air days. No unhealthy air days were recorded in 2024.

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 better than US avg
New Castle, IN 78.1%
Clarksburg, WV 80.5%
US average 70.2%
Median AQI better than US avg
New Castle, IN 34
Clarksburg, WV 34
US average 41
Unhealthy days / yr better than US avg
New Castle, IN 0
Clarksburg, WV 0
US average 1

5-Year Air Quality Trend

Air quality is improving in the New Castle, IN metro. Best year: 2024 (282 good 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

Metros with Similar Air Quality

Metro areas across the US with a similar median AQI to New Castle, IN.

Clarksburg, WV

AQI 34 · 80.5% good

34

Kinston, NC

AQI 34 · 95.8% good

34

Sioux Falls, SD

AQI 34 · 81.4% good

34

St. Marys, PA

AQI 34 · 95.8% good

34

Arkadelphia, AR

AQI 35 · 93.3% good

35

Atlantic City-Hammonton, NJ

AQI 35 · 82.5% good

35

More Air Quality Data

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Worst Air Quality

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All Metro Areas

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Air Quality Guides

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Understanding AQI

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Health Effects of Air Pollution

How PM2.5 and ozone exposure affects respiratory and cardiovascular health.

Frequently Asked Questions

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 34, rated "Good." 78.1% of monitored days (282 out of 361) had good air quality in 2024.
How many unhealthy air days does New Castle, IN have? ▼
In 2024, the New Castle, IN metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 75.
Is air quality in New Castle, IN getting better or worse? ▼
Air quality in the New Castle, IN metro is improving based on 5-year trends (2020-2024). Best year: 2024 with 282 good days. Worst year: 2021 with 78 good days.
What does AQI 34 mean for health? ▼
An AQI of 34 is "Good", air quality is satisfactory and poses little or no health risk. This is the best category on the EPA's AQI scale.
What is the 90th percentile AQI for New Castle, IN? ▼
The 90th percentile AQI for the New Castle, IN metro area is 55, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 75 (Moderate).
How does New Castle, IN compare to other metro areas? ▼
The New Castle, IN metro has 78.1% good air days. Similar metros: Clarksburg, WV (80.5% good), Kinston, NC (95.8% good), Sioux Falls, SD (81.4% good).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2024. The AQS collects ambient air monitoring data from state, local, and tribal monitoring agencies across the United States.

Metrics: Air Quality Index (AQI) is calculated using EPA-standard breakpoints for six criteria pollutants: PM2.5, PM10, Ozone, NO2, CO, and SO2. Median AQI, max AQI, and 90th percentile AQI are computed from daily measurements. Good days percentage reflects days with AQI 0–50.

Coverage: 501 metro areas (Core Based Statistical Areas). Only metros with active monitoring stations are included. Unmonitored areas are not represented.

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

Source: U.S. EPA, AirNow / AQS Air Quality Index readings and pollutant concentrations · 2025