EnviroNearby

La Paz County, Arizona air quality history

Daily Air Quality Index summaries from EPA monitors in La Paz, Arizona, 2005–2025.

77%
Good days in 2025
44
Median daily AQI, 2025
1
Days above 100 in 2025
363
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for La Paz, Arizona on 363 days. 278 of those days (77%) were in the Good range, and the median daily AQI was 44. That median is lower than the typical monitored county in Arizona (median 47 across 13 counties), and higher than the typical monitored U.S. county (40). The main pollutant was ozone on 335 days. Across the years with fuller monitoring, the share of Good days rose: an average of 50% in 2005–2007 versus 70% in 2023–2025.

How the days broke down each year

Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.

Share of monitored days in each AQI category, by year0%25%50%75%100%2005: Good 68 of 130 days2005: Moderate 56 of 130 days2005: Unhealthy for Sensitive Groups 6 of 130 days20052006: Good 98 of 214 days2006: Moderate 107 of 214 days2006: Unhealthy for Sensitive Groups 9 of 214 days2007: Good 112 of 212 days2007: Moderate 94 of 212 days2007: Unhealthy for Sensitive Groups 6 of 212 days20072008: Good 105 of 178 days2008: Moderate 66 of 178 days2008: Unhealthy for Sensitive Groups 7 of 178 days2009: Good 130 of 213 days2009: Moderate 81 of 213 days2009: Unhealthy for Sensitive Groups 2 of 213 days20092010: Good 121 of 213 days2010: Moderate 88 of 213 days2010: Unhealthy for Sensitive Groups 4 of 213 days2011: Good 104 of 196 days2011: Moderate 84 of 196 days2011: Unhealthy for Sensitive Groups 8 of 196 days20112012: Good 140 of 239 days2012: Moderate 88 of 239 days2012: Unhealthy for Sensitive Groups 11 of 239 days2013: Good 148 of 240 days2013: Moderate 87 of 240 days2013: Unhealthy for Sensitive Groups 5 of 240 days20132014: Good 264 of 358 days2014: Moderate 90 of 358 days2014: Unhealthy for Sensitive Groups 4 of 358 days2015: Good 273 of 360 days2015: Moderate 84 of 360 days2015: Unhealthy for Sensitive Groups 3 of 360 days20152016: Good 290 of 365 days2016: Moderate 74 of 365 days2016: Unhealthy for Sensitive Groups 1 of 365 days2017: Good 273 of 361 days2017: Moderate 86 of 361 days2017: Unhealthy for Sensitive Groups 2 of 361 days20172018: Good 257 of 364 days2018: Moderate 104 of 364 days2018: Unhealthy for Sensitive Groups 3 of 364 days2019: Good 303 of 364 days2019: Moderate 61 of 364 days20192020: Good 292 of 366 days2020: Moderate 72 of 366 days2020: Unhealthy for Sensitive Groups 2 of 366 days2021: Good 254 of 362 days2021: Moderate 107 of 362 days2021: Unhealthy 1 of 362 days20212022: Good 275 of 359 days2022: Moderate 83 of 359 days2022: Unhealthy for Sensitive Groups 1 of 359 days2023: Good 257 of 364 days2023: Moderate 104 of 364 days2023: Unhealthy for Sensitive Groups 3 of 364 days20232024: Good 224 of 363 days2024: Moderate 135 of 363 days2024: Unhealthy for Sensitive Groups 4 of 363 days2025: Good 278 of 363 days2025: Moderate 84 of 363 days2025: Very Unhealthy 1 of 363 days2025
  • Good
  • Moderate
  • Unhealthy for Sensitive Groups
  • Unhealthy
  • Very Unhealthy
  • Hazardous

Typical and high-end AQI over time

The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.

Median and 90th-percentile daily AQI, by year0501002005: 90th percentile AQI 902006: 90th percentile AQI 902007: 90th percentile AQI 872008: 90th percentile AQI 932009: 90th percentile AQI 712010: 90th percentile AQI 802011: 90th percentile AQI 872012: 90th percentile AQI 902013: 90th percentile AQI 802014: 90th percentile AQI 672015: 90th percentile AQI 672016: 90th percentile AQI 672017: 90th percentile AQI 642018: 90th percentile AQI 712019: 90th percentile AQI 582020: 90th percentile AQI 582021: 90th percentile AQI 712022: 90th percentile AQI 642023: 90th percentile AQI 742024: 90th percentile AQI 772025: 90th percentile AQI 642005: Median AQI 502006: Median AQI 542007: Median AQI 502008: Median AQI 482009: Median AQI 492010: Median AQI 482011: Median AQI 502012: Median AQI 492013: Median AQI 482014: Median AQI 442015: Median AQI 422016: Median AQI 422017: Median AQI 442018: Median AQI 442019: Median AQI 442020: Median AQI 442021: Median AQI 462022: Median AQI 442023: Median AQI 452024: Median AQI 472025: Median AQI 4420052007200920112013201520172019202120232025
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2025

On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.

PollutantDays as main pollutantShare of monitored days
Ozone33592%
Fine particles (PM2.5)185%
Coarse particles (PM10)103%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253632788400104464253Ozone
202436322413540004777105Ozone
202336425710430004574126Ozone
20223592758310004464130Ozone
202136225410701004671187Ozone
20203662927220004458125Ozone
2019364303610000445877Ozone
201836425710430004471105Ozone
20173612738620004464105Ozone
20163652907410004267101Ozone
20153602738430004267108Ozone
20143582649040004467136Ozone
20132401488750004880115Ozone
201223914088110004990115Ozone
20111961048480005087136Ozone
20102131218840004880105Ozone
20092131308120004971112Ozone
20081781056670004893143Ozone
20072121129460005087136Ozone
20062149810790005490119Ozone
2005130685660005090119Ozone

What this data can and can’t tell you

It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.

It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.

Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.

Counties in Arizona with a similar median AQI in 2025

All monitored counties in Arizona

Source: U.S. EPA AirData, “Annual AQI by County” files for 2005–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem