What Is the Air Quality in Maricopa, Arizona?
Maricopa, Arizona has an Air Quality Grade of F (very poor) with a 5-year median AQI of 90. The dominant pollutant is Ground-Level Ozone, and air quality has been worsening over the past decade.
Maricopa, Arizona Air Quality Snapshot
| Air Quality Grade | F9/100 |
| 5-Year Median AQI | 90 (Moderate) |
| Most Recent Median AQI (2023) | 72 (Moderate) |
| Dominant Pollutant | Ground-Level Ozone |
| 10-Year Trend | Worsening (+2.93 AQI/yr) |
| Unhealthy Days (last 5 yr) | 628 |
| National Rank (cleanest = #1) | #1020 of 1,020 (100th most polluted percentile) |
| Arizona Rank | #13 of 13 |
What Does the F Grade Mean?
Maricopa, Arizona earns an F — among the most polluted areas tracked by EPA monitoring, with a 5-year median AQI of 90. The city sees a high count of unhealthy air days, and residents with respiratory or cardiovascular conditions should treat AQI forecasts as a serious daily input.
Maricopa, Arizona's 5-year median AQI of 90 is 49 points above the national average of 41 — meaningfully more polluted than the typical U.S. metro tracked here. Within Arizona, Maricopa, Arizona runs more polluted than the state average of 46 — local sources or geography are concentrating pollution above the state's typical reading.
For context within Arizona: Apache, Arizona currently holds the state's cleanest grade (A, AQI 13), while Pinal, Arizona sits at the bottom (D, AQI 66).
What's in Maricopa, Arizona's Air?
The dominant pollutant in Maricopa, Arizona is Ground-Level Ozone. Ground-level ozone forms when sunlight reacts with vehicle exhaust and industrial emissions. It is worst on hot, sunny, stagnant summer days. Ozone irritates the lungs, triggers asthma attacks, and reduces lung function — even healthy adults can feel chest tightness and shortness of breath after exercising in elevated ozone.
Days by Dominant Pollutant (2023)
| Pollutant | Days as Dominant | Share of Year |
|---|---|---|
| Ground-Level Ozone | 193 | 53% |
| Fine Particulate Matter (PM2.5) | 91 | 25% |
| Coarse Particulate Matter (PM10) | 81 | 22% |
Is the Air Getting Better or Worse?
Air quality in Maricopa, Arizona has been getting worse over the past decade, with median AQI climbing by roughly 2.9 points per year. That bucks the national trend of broad improvement, and most often reflects either growing wildfire smoke exposure (particularly across the West) or rising local emissions from population and freight growth.
In 2014, Maricopa, Arizona posted a median AQI of 69. By 2023 that figure was 72 — a rise of 3 AQI points dirtier across 10 years of EPA records.
Year-by-Year AQI in Maricopa, Arizona
| Year | Median AQI | Good Days | Unhealthy Days | Dominant Pollutant |
|---|---|---|---|---|
| 2014 | 69 | 32 | 45 | Ozone |
| 2015 | 66 | 62 | 36 | Ozone |
| 2016 | 67 | 47 | 37 | Ozone |
| 2017 | 71 | 38 | 55 | Ozone |
| 2018 | 71 | 49 | 64 | Ozone |
| 2019 | 67 | 50 | 38 | Ozone |
| 2020 | 112 | 11 | 201 | Ozone |
| 2021 | 122 | 12 | 225 | Ozone |
| 2022 | 75 | 27 | 96 | Ozone |
| 2023 | 72 | 41 | 68 | Ozone |
Health Context for Maricopa, Arizona
Across the past five years, this area has logged 628 days where AQI rose into the "Unhealthy for Sensitive Groups" range or worse — about 126 days per year, or roughly one in three days on the calendar. That count places this area in the worst tier nationally and is the dominant driver of the F grade.
Treat daily AQI forecasts as essential input. On flagged days, sensitive groups (asthma, COPD, heart disease, pregnancy, young children, older adults) should limit outdoor exertion and keep windows closed. A HEPA air cleaner sized to a bedroom or family room can cut indoor PM2.5 by 80%+ during smoke or pollution events. Because ozone peaks in the afternoon on hot sunny days, plan outdoor exercise for early morning or after sunset on bad-air days.
How This Grade Is Calculated
The AirHistory Air Quality Grade combines four signals: the 5-year median AQI (40% of the score), the 10-year trend direction (30%), the count of unhealthy days per year (20%), and the dominant pollutant type (10%). All four come directly from the EPA Air Quality System (AQS), which aggregates readings from federally certified monitors. Read the full methodology.
Maricopa, Arizona has an Air Quality Grade of F (very poor) with a 5-year median AQI of 90. The dominant pollutant is Ground-Level Ozone, and air quality has been worsening over the past decade.
The data source behind this answer is the EPA Air Quality System (AQS). Every figure on the page traces back to that source; the methodology page describes the inputs and the refresh cadence in full detail.
A practical caveat: the headline answer above reflects the most recent the EPA Air Quality System (AQS) vintage; underlying data is often revised for months after first publication, and the right reference for any specific decision is whichever vintage is current at the time of the decision. The as-of date is stamped on every page.
Source: EPA Outdoor Air Quality Data, 2026.