Mesa Air Quality in 2020

In 2020, Mesa's air quality (Phoenix-Mesa-Scottsdale, AZ area) had a median daily AQI of 120 (Unhealthy for Sensitive Groups) across 366 monitored days. 231 days (63.1%) reached Unhealthy for Sensitive Groups or worse, 7 were Good, and the year's peak AQI was 1194 (Hazardous). Ground-level ozone set the daily AQI on 222 of those days. The cleanest month of 2020 was January (median AQI 75, 8 days above 100) and the worst was April (median 210, 30 days above 100, peak 240).

120
Median AQI
Unhealthy for Sensitive Groups
231
Days above AQI 100
63.1% of 366 days
217
90th percentile AQI
worst 1 day in 10
1194
Peak AQI
Hazardous
O3
Main pollutant
222 of 366 days
7
Good days
1.9% of days
  • Good: 1.9%
  • Moderate: 35.0%
  • Unhealthy for Sensitive Groups: 23.2%
  • Unhealthy or worse: 39.9%

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QUICK ANSWER

How was Mesa's air quality in 2020?

Unhealthy for Sensitive Groups on a typical day: median AQI 120, with 231 days above AQI 100 out of 366 monitored — the 6th cleanest of 7 years on record for the area.

  • Peak AQI in 2020: 1194 (Hazardous).
  • Ground-level ozone was the main pollutant on 222 days.
  • Cleanest month: January; worst: April.

Frequently asked questions

What was the average AQI in Mesa in 2020?

EPA's Air Quality System puts Mesa's (Phoenix-Mesa-Scottsdale, AZ) median daily AQI for 2020 at 120, which is Unhealthy for Sensitive Groups. 231 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 1194.

Which month had the worst air quality in Mesa in 2020?

The cleanest month of 2020 was January (median AQI 75, 8 days above 100) and the worst was April (median 210, 30 days above 100, peak 240).

Was 2020 a good or bad year for Mesa's air?

Among the 7 years EPA has published for the area (2019–2025), 2020 ranks 6th cleanest by days above AQI 100. 2020's median of 120 is above the area's typical annual median of 79.

Mesa month by month in 2020

Mesa air quality month by month, 2020 (Phoenix-Mesa-Scottsdale, AZ, EPA AQS daily AQI)

MonthDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
Januarycleanest31758224PM2.5
February2915027214O3
March3117229274O3
Aprilworst3021030240O3
May319010147O3
June30849130O3
July3114321237O3
August31213301194O3
September309714164PM10
October3119231223O3
November309513522PM10
December31829161PM2.5

How 2020 compares

Among the 7 years EPA has published for the area (2019–2025), 2020 ranks 6th cleanest by days above AQI 100.

2020's median of 120 is above the area's typical annual median of 79.

Activity-specific thresholds: running, cycling, kids' sports.

Right now in Mesa

The latest EPA AirNow observation puts Mesa's AQI at 57 (PM10). The figures above are multi-year annual statistics, not today's reading.

View current Mesa air quality →

Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Phoenix-Mesa-Scottsdale, AZ), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.