Metro area air quality · 2025

Lancaster, PA

Median AQI 45 (Good). 60.5% of monitored days rated Good across this metro's EPA monitoring network.

45
Median AQI
60.5%
Good-air days
0
Unhealthy days
26%
Cleaner than US metros

Lancaster, PA posted a 2025 median AQI of 45 (Good) with 60.5% Good days

According to the U.S. EPA Air Quality System, the Lancaster, PA CBSA recorded a median AQI of 45 across 365 monitored days in 2025, with 60.5% 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 Lancaster, PA CBSA's 60.5% Good-day share places it cleaner than 26% of US metros in 2025.
Closest median-AQI peer
Akron, OH (61.6% Good, median AQI 45) is the closest nationwide median-AQI peer to Lancaster, PA.
2020–2025 Good-day shift
Lancaster, PA's Good-day share moved +12.0 points from 2020 to 2025 (median AQI -6).
Median AQI
Median AQI: 45

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

The verdict

Lancaster, PA lands in the lower Good-day tercile (60.5% Good), a thinner clean-air share than most CBSA peers here. On the EPA scale the metro runs good, more polluted than the median US metro, with a median AQI of 45 and 60.5% of 365 monitored days in the Good band.

45
median AQI · Good
60.5%
days rated Good
26%
cleaner than US metros
119
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
  • Lancaster, PA metro's Good-day share rose from 52.1% to 60.9% between the 2024 and 2025 EPA annual releases, a change of +8.8 percentage points.
  • Lancaster, PA metro's median AQI fell from 50 to 45 between the 2024 and 2025 EPA annual releases, a change of -5 points.

Compared against 363 monitored days in 2024 and 363 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

Lancaster, PA lands in the lower Good-day tercile (60.5% Good), a thinner clean-air share than most CBSA peers here. Signature read: 60.5% Good-day share (low tercile vs CBSA corpus). Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 45 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 221 Good (61%), 142 Moderate (39%), and 2 Unhealthy-for-Sensitive-Groups (1%). The 90th-percentile AQI finished at 71; the highest single-day reading hit 119 (USG).

Across 2020–2025, Good-day share shifted +12.0 points and median AQI moved -6 (improving). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Akron, OH (61.6% good, AQI 45); Ardmore, OK (67.9% good, AQI 45); Asheville, NC (69.9% good, AQI 45).

Health effects of air pollution →

Air Quality Summary

Median AQI

45

Good

Good Days

60.5%

221 of 365 days

Max AQI

119

USG

Health Grade

Moderate

90th pct: 71

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

221

61%

Moderate

142

39%

USG

2

1%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Moderate

The Lancaster, PA metro area's air quality is rated Moderate based on 60.5% 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 Lancaster, PA metro compare?

How Lancaster, PA compares

Good-day share worse than typical
Lancaster, PA 60.5%
Akron, OH 61.6%
Typical US metro 70.6%
Median AQI worse than typical
Lancaster, PA 45
Akron, OH 45
Typical US metro 41
Unhealthy days / yr better than typical
Lancaster, PA 0
Akron, OH 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is improving in the Lancaster, PA metro. Highest Good-day share: 2025 (60.9%, 221 of 363 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 177 184 1 51
2021 100 257 1 56
2022 84 274 1 59
2023 108 243 3 58
2024 189 174 0 50
2025 221 142 0 45

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Lancaster, PA (45).

Akron, OH

Median AQI 45 · 61.6% Good-day share

45

Ardmore, OK

Median AQI 45 · 67.9% Good-day share

45

Asheville, NC

Median AQI 45 · 69.9% Good-day share

45

Cheyenne, WY

Median AQI 45 · 75.1% Good-day share

45

Clinton, IA

Median AQI 45 · 59.5% Good-day share

45

Fort Dodge, IA

Median AQI 45 · 59.2% Good-day share

45

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Lancaster, PA'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

Albany, GA

0 unhealthy-or-worse days · median AQI 46

46

Albany, OR

0 unhealthy-or-worse days · median AQI 27

27

Albany-Schenectady-Troy, NY

0 unhealthy-or-worse days · median AQI 41

41

Frequently Asked Questions

How many unhealthy air days does Lancaster, PA have? ▼
In 2025, the Lancaster, PA metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 119.
What is the air quality in the Lancaster, PA metro area? ▼
The Lancaster, PA metro area has a median Air Quality Index (AQI) of 45, rated "Good." 60.5% of monitored days (221 out of 365) had good air quality in 2025.
Is air quality in Lancaster, PA getting better or worse? ▼
Air quality in the Lancaster, PA 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 60.9% (221 of 363 days). Lowest qualifying Good-day share: 2022 at 23.4% (84 of 359 days).
What does AQI 45 mean for health? ▼
An AQI of 45 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 Lancaster, PA compare to other metro areas? ▼
The Lancaster, PA metro has 60.5% good air days. Similar metros: Akron, OH (61.6% good), Ardmore, OK (67.9% good), Asheville, NC (69.9% good).
What is the 90th percentile AQI for Lancaster, PA? ▼
The 90th percentile AQI for the Lancaster, PA metro area is 71, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 119 (USG).

Data Sources

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