Metro area air quality · 2025

Nashville-Davidson--Murfreesboro--Franklin, TN

Median AQI 50 (Good). 51.2% of monitored days rated Good across this metro's EPA monitoring network.

50
Median AQI
51.2%
Good-air days
0
Unhealthy days
14%
Cleaner than US metros

Nashville-Davidson--Murfreesboro--Franklin, TN posted a 2025 median AQI of 50 (Good) with 51.2% Good days

According to the U.S. EPA Air Quality System, the Nashville-Davidson--Murfreesboro--Franklin, TN CBSA recorded a median AQI of 50 across 365 monitored days in 2025, with 51.2% 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 Nashville-Davidson--Murfreesboro--Franklin, TN CBSA's 51.2% Good-day share places it cleaner than 14% of US metros in 2025.
Closest median-AQI peer
Fort Collins, CO (50.7% Good, median AQI 50) is the closest nationwide median-AQI peer to Nashville-Davidson--Murfreesboro--Franklin, TN.
2020–2025 Good-day shift
Nashville-Davidson--Murfreesboro--Franklin, TN's Good-day share moved +2.5 points from 2020 to 2025 (median AQI -1).
Median AQI
Median AQI: 50

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

The verdict

Nashville-Davidson--Murfreesboro--Franklin, TN lands in the lower Good-day tercile (51.2% Good), a thinner clean-air share than most CBSA peers here. On the EPA scale the metro runs good, among the more polluted US metros, with a median AQI of 50 and 51.2% of 365 monitored days in the Good band.

50
median AQI · Good
51.2%
days rated Good
14%
cleaner than US metros
136
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
  • Nashville-Davidson--Murfreesboro--Franklin, TN metro's Good-day share rose from 47.9% to 51.4% between the 2024 and 2025 EPA annual releases, a change of +3.5 percentage points.

Compared against 359 monitored days in 2024 and 364 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

Nashville-Davidson--Murfreesboro--Franklin, TN lands in the lower Good-day tercile (51.2% Good), a thinner clean-air share than most CBSA peers here. Signature read: 51.2% 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 50 over 365 measured days in 2025 (Good / Moderate). The monitored-day split lands at 187 Good (51%), 177 Moderate (48%), and 1 Unhealthy-for-Sensitive-Groups (0%). The 90th-percentile AQI finished at 67; the highest single-day reading hit 136 (USG).

Across 2020–2025, Good-day share shifted +2.5 points and median AQI moved -1 (stable). No Unhealthy-tier days appear in this annual dataset. Metros with comparable AQI profiles include Fort Collins, CO (50.7% good, AQI 50); Madera, CA (50.4% good, AQI 50); Merced, CA (51.0% good, AQI 50).

Health effects of air pollution →

Air Quality Summary

Median AQI

50

Good

Good Days

51.2%

187 of 365 days

Max AQI

136

USG

Health Grade

Moderate

90th pct: 67

AQI Day Breakdown (2025)

Distribution of 365 monitored days across EPA AQI categories.

Good

187

51%

Moderate

177

48%

USG

1

0%

Unhealthy

0

0%

Very Unhealthy

0

0%

Hazardous

0

0%

Health Impact Assessment

Moderate

The Nashville-Davidson--Murfreesboro--Franklin, TN metro area's air quality is rated Moderate based on 51.2% 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 Nashville-Davidson--Murfreesboro--Franklin, TN metro compare?

How Nashville-Davidson--Murfreesboro--Franklin, TN compares

Good-day share worse than typical
Nashville-Davidson--Murfreesboro--Franklin, TN 51.2%
Fort Collins, CO 50.7%
Typical US metro 70.6%
Median AQI worse than typical
Nashville-Davidson--Murfreesboro--Franklin, TN 50
Fort Collins, CO 50
Typical US metro 41
Unhealthy days / yr better than typical
Nashville-Davidson--Murfreesboro--Franklin, TN 0
Fort Collins, CO 0
Typical US metro 1

5-Year Air Quality Trend

Air quality is stable in the Nashville-Davidson--Murfreesboro--Franklin, TN metro. Highest Good-day share: 2025 (51.4%, 187 of 364 monitored days).

Year Good Moderate Unhealthy Median AQI
2020 178 186 0 51
2021 138 222 0 53
2022 164 197 0 52
2023 128 227 0 54
2024 172 187 0 51
2025 187 177 0 50

Metros with a similar median AQI

CBSA peers nationwide whose annual median AQI sits near Nashville-Davidson--Murfreesboro--Franklin, TN (50).

Fort Collins, CO

Median AQI 50 · 50.7% Good-day share

50

Madera, CA

Median AQI 50 · 50.4% Good-day share

50

Merced, CA

Median AQI 50 · 51.0% Good-day share

50

Oxnard-Thousand Oaks-Ventura, CA

Median AQI 50 · 52.0% Good-day share

50

Reno, NV

Median AQI 50 · 50.1% Good-day share

50

San Luis Obispo-Paso Robles-Arroyo Grande, CA

Median AQI 50 · 52.3% Good-day share

50

Metros with similar unhealthy-day exposure

A second relationship type: metros whose unhealthy-or-worse day count is closest to Nashville-Davidson--Murfreesboro--Franklin, TN'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 Nashville-Davidson--Murfreesboro--Franklin, TN have? ▼
In 2025, the Nashville-Davidson--Murfreesboro--Franklin, TN metro area recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 136.
What is the air quality in the Nashville-Davidson--Murfreesboro--Franklin, TN metro area? ▼
The Nashville-Davidson--Murfreesboro--Franklin, TN metro area has a median Air Quality Index (AQI) of 50, rated "Good." 51.2% of monitored days (187 out of 365) had good air quality in 2025.
Is air quality in Nashville-Davidson--Murfreesboro--Franklin, TN getting better or worse? ▼
Air quality in the Nashville-Davidson--Murfreesboro--Franklin, TN 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 51.4% (187 of 364 days). Lowest qualifying Good-day share: 2023 at 36.1% (128 of 355 days).
What does AQI 50 mean for health? ▼
An AQI of 50 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 Nashville-Davidson--Murfreesboro--Franklin, TN compare to other metro areas? ▼
The Nashville-Davidson--Murfreesboro--Franklin, TN metro has 51.2% good air days. Similar metros: Fort Collins, CO (50.7% good), Madera, CA (50.4% good), Merced, CA (51.0% good).
What is the 90th percentile AQI for Nashville-Davidson--Murfreesboro--Franklin, TN? ▼
The 90th percentile AQI for the Nashville-Davidson--Murfreesboro--Franklin, TN metro area is 67, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 136 (USG).

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset for Nashville-Davidson--Murfreesboro--Franklin, TN, 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, Nashville-Davidson--Murfreesboro--Franklin, TN · 2020–2025