Median AQI
44
Good
Arizona · County air quality · 2025
La Paz County, Arizona
Median AQI 44 (Good). 76.6% of monitored days rated Good, direct from EPA Air Quality System stations.
- 44
- Median AQI
- 76.6%
- Good-air days
- 1
- Unhealthy days
- 48%
- Cleaner than US counties
La Paz County's 2025 annual median AQI is 44 (Good), with 76.6% Good days
According to the U.S. EPA Air Quality System, La Paz County, Arizona posted a 2025 median AQI of 44 (Good) across 363 monitored days, with 76.6% rated Good and 1 unhealthy or worse. This is an annual comparison, not today's advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US
- La Paz County's 76.6% Good-day share places it cleaner than 48% of US counties in 2025.
- Closest median-AQI peer
- Allegan County (63.9% Good, median AQI 44) is the closest nationwide median-AQI peer to La Paz County.
- 2020–2025 trend
- La Paz County's floor-qualifying Good-day share is stable from 2020 to 2025 (79.8% → 76.8%).
- Median AQI
- Median AQI: 44
The verdict
According to EPA Air Quality System monitoring data, La Paz County's air is good on balance, more polluted than the median US county, a median AQI of 44 with 76.6% of 363 monitored days in the Good band, driven mainly by Ozone.
- 44
- median AQI · Good
- 76.6%
- days rated Good
- Ozone
- main pollutant
- 48%
- cleaner than US counties
1 day reached Unhealthy or worse; the worst single reading hit AQI 253.
Annual release change
What changed in the 2025 EPA annual release
- La Paz County's Good-day share rose from 61.7% to 76.6% between the 2024 and 2025 EPA annual releases, a change of +14.9 percentage points.
- La Paz County's peak single-day AQI rose from 105 to 253 between the 2024 and 2025 EPA annual releases, a change of +148 points.
- La Paz County's median AQI fell from 47 to 44 between the 2024 and 2025 EPA annual releases, a change of -3 points.
Data updated August 2026
- Good · 278 d · 76.6%
- Moderate · 84 d · 23.1%
- Very Unhealthy · 1 d · 0.3%
How did La Paz County's air break down in 2025?
Across 363 monitored days, 278 fell in the Good band (AQI 0–50) and 1 reached Unhealthy or worse. The worst single day peaked at AQI 253 (Very Unhealthy).
EPA AQS →Air quality data from EPA Air Quality System (2025). 363 days monitored. Median AQI: 44 (Good).
Insights: La Paz County, Arizona. EPA monitors recorded a median Air Quality Index of 44 across 363 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 278 (77%) fell in the Good band (AQI 0–50), 84 (23%) registered Moderate readings, and 0 (0%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 64, while the worst single-day peak hit 253 (Very Unhealthy). Residents averaged about 23.0 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (335 days), PM2.5 (18 days), PM10 (10 days). Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -3.2 points and the median AQI moved +0 points, placing the multi-year trajectory at stable. The annual record contains 1 day at Unhealthy or worse. On that day, the EPA recommends that sensitive groups limit prolonged outdoor exertion. Nearby counties show comparable readings: Apache (86.2% good, AQI 33); Cochise (69.9% good, AQI 45); Coconino (70.1% good, AQI 46); Gila (62.7% good, AQI 47); Maricopa (8.8% good, AQI 73); Mohave (94.8% good, AQI 17).
Air Quality Summary
Good Days
76.6%
278 of 363 monitored days
1.6pp vs 75% target
Max AQI Recorded
253
Very Unhealthy
Health Grade
Good
90th-pct AQI 64
La Paz County, Good days share 76.6%
National avg
Share of monitored days at AQI 0-50 (Good band).
La Paz County, Unhealthy-or-worse share 2.8%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 363 monitored days across EPA AQI categories.
Good
278
77%
Moderate
84
23%
USG
0
0%
Unhealthy
0
0%
Very Unhealthy
1
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in La Paz County.
- Ozone · 335 days · 92.3%
- PM2.5 · 18 days · 5.0%
- PM10 · 10 days · 2.8%
Health Impact Assessment
Good
La Paz County's air quality is rated Good based on 76.6% good air days. There were 1 unhealthy days in 2025 when outdoor activity should be limited.
Air quality reached unhealthy levels on 1 days in 2025 (0 Unhealthy, 1 Very Unhealthy). Sensitive groups, including people with asthma, COPD, cardiovascular conditions, children, and adults over 65, should review the daily breakdown below and follow local air-quality advisories on high-AQI days.
Sensitive group advisory
People with asthma, COPD, heart disease, children, pregnant women, and adults 65+ should follow EPA AQI alerts daily and limit outdoor exertion when AQI exceeds 100. Real-time conditions: airnow.gov.
The dominant pollutant is Ozone, driving AQI on 335 of 363 monitored days.
5-Year Air Quality Trend
Air quality is stable in La Paz County. Highest Good-day share: 2020 (79.8%, 292 of 366 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 292 | 72 | 2 | 0 | 44 | 125 |
| 2021 | 254 | 107 | 0 | 1 | 46 | 187 |
| 2022 | 275 | 83 | 1 | 0 | 44 | 130 |
| 2023 | 257 | 104 | 3 | 0 | 45 | 126 |
| 2024 | 224 | 135 | 4 | 0 | 47 | 105 |
| 2025 | 278 | 84 | 0 | 0 | 44 | 253 |
How does La Paz County compare?
How La Paz County compares
Good-day share better than typical
La Paz County 76.6%
Allegan County, Michigan 63.9%
Typical US county 76.0%
Median AQI worse than typical
La Paz County 44
Allegan County, Michigan 44
Typical US county 39
Unhealthy days / yr about typical
La Paz County 1
Allegan County, Michigan 2
Typical US county 1
Counties with a similar median AQI
Nationwide peers within about the same annual median AQI as La Paz County (44), not geographic neighbors.
Allegan County, Michigan
Median AQI 44 · 63.9% Good-day share
Allen County, Indiana
Median AQI 44 · 60.0% Good-day share
Baker County, Florida
Median AQI 44 · 69.5% Good-day share
Bay County, Florida
Median AQI 44 · 66.4% Good-day share
Blount County, Tennessee
Median AQI 44 · 71.5% Good-day share
Cache County, Utah
Median AQI 44 · 66.0% Good-day share
Same primary pollutant: Ozone
Ozone led the AQI on the most monitored days here. These peers share that driver and the closest Good-day share (a second relationship type beyond median-AQI neighbors).
York County, South Carolina
76.5% Good-day share · median AQI 43
Lee County, Florida
76.4% Good-day share · median AQI 40
Blair County, Pennsylvania
76.9% Good-day share · median AQI 40
Cumberland County, New Jersey
76.2% Good-day share · median AQI 40
Franklin County, Massachusetts
76.9% Good-day share · median AQI 38
Cass County, North Dakota
76.2% Good-day share · median AQI 37
Arizona counties on the map
Geographic containment only, other monitored counties in Arizona, independent of AQI or pollutant match.
What La Paz County's air means for you
On most days the air here is fine, but Ozone drives 1 unhealthy-or-worse day a year that sensitive groups should plan around.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-Ozone days, the guide explains what a median of 44 means for exposure. Health guidance
- See how La Paz County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare La Paz County with its Arizona neighbours before drawing a conclusion about the region. All of Arizona
Based on 363 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
Keep exploring the annual AQI record
Air-quality reading list
Frequently Asked Questions
What is the air quality in La Paz County, Arizona? ▼
La Paz County has a median Air Quality Index (AQI) of 44, rated "Good." 76.6% of monitored days (278 out of 363) had good air quality in 2025.
What is the main pollutant in La Paz County? ▼
The primary pollutant in La Paz County is Ozone (O3), which was the main AQI driver on 335 days (92% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does La Paz County have? ▼
In 2025, La Paz County recorded 1 unhealthy air days (0 Unhealthy, 1 Very Unhealthy, 0 Hazardous). The maximum AQI reached 253.
Is the air quality in La Paz County getting better or worse? ▼
Air quality in La Paz County 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: 2020 at 79.8% (292 of 366 days). Lowest qualifying Good-day share: 2024 at 61.7% (224 of 363 days).
What does AQI 44 mean for health? ▼
La Paz County's median AQI of 44 falls in the "Good" category. See the AQI category guide for what each range means for health.
How does La Paz County compare to other counties in Arizona? ▼
La Paz County has 76.6% good air days. Nearby counties in Arizona: Apache (86.2% good), Cochise (69.9% good), Coconino (70.1% good), Gila (62.7% good), Maricopa (8.8% good), Mohave (94.8% good).
What is the 90th percentile AQI in La Paz County? ▼
The 90th percentile AQI for La Paz County is 64, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 253 (Very Unhealthy).
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer. Spotted a figure that looks wrong? Report a correction.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for La Paz County, Arizona · 2020–2025
Share this annual record
Send the source-year summary or download its ready-to-use data card.
Download this county's annual AQI row as CSV , with the same EPA fields and denominator shown on this page.
Every figure on PlainAirData is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.