Tucson Best & Worst AQI Days: Air Quality Guide
The worst air quality day on record for Tucson (Tucson, AZ area) was July 1, 2025, when the daily AQI reached 357 (Hazardous), set by coarse dust (PM10). Across 2,557 monitored days in 2019–2025, 9 of the 10 worst days were Unhealthy (AQI 151+) or worse; 9 of the 10 were driven by coarse dust (PM10) and 1 by fine particulate matter (PM2.5), and 5 of them fell in 2025. The cleanest day was September 26, 2019 at AQI 23 (Good); the 10 best days span 5 different years.
Reduce Indoor Ozone in Tucson
Today's main pollutant in Tucson is ground-level ozone (AQI 35). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
As an Amazon Associate, we earn from qualifying purchases.
When were Tucson's worst and best air quality days?
Worst: July 1, 2025, AQI 357 (Hazardous, PM10). Best: September 26, 2019, AQI 23 (Good). Based on 2,557 EPA-monitored days in the Tucson, AZ area, 2019–2025.
- ✓9 of the 10 worst days were Unhealthy (AQI 151+) or worse; the 10th-worst was AQI 148 (Unhealthy for Sensitive Groups).
- ✓Coarse dust (PM10) drove 9 of the 10 worst days.
- ✓2025 accounts for 5 of the 10 worst days.
Frequently asked questions
What was the worst air quality day in Tucson?▾
July 1, 2025: the Tucson, AZ area's daily AQI hit 357 (Hazardous), driven by coarse dust (PM10). That is the highest of 2,557 monitored days in 2019–2025.
What was the best air quality day in Tucson?▾
September 26, 2019, with a daily AQI of 23 (Good). The daily AQI is the highest reading from any monitor in the area, so even the cleanest day reflects the area's worst monitor.
What was Tucson's worst air quality day in 2025?▾
July 1, 2025, AQI 357 (Hazardous), set by coarse dust (PM10).
Which pollutant causes Tucson's worst air days?▾
Coarse dust (PM10) set the AQI on 9 of the 10 worst days; fine particulate matter (PM2.5) on 1. The tables above list the defining pollutant for every day.
Tucson's 10 worst air quality days, 2019–2025
Highest daily AQI recorded for the Tucson, AZ area (EPA AQS). The daily AQI is the highest reading from any monitor in the area that day.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2025 page) | 357 | Hazardous | PM10 — coarse dust (PM10) |
| 2 | (2021 page) | 313 | Hazardous | PM10 — coarse dust (PM10) |
| 3 | (2020 page) | 277 | Very Unhealthy | PM10 — coarse dust (PM10) |
| 4 | (2025 page) | 251 | Very Unhealthy | PM10 — coarse dust (PM10) |
| 5 | (2025 page) | 189 | Unhealthy | PM10 — coarse dust (PM10) |
| 6 | (2025 page) | 174 | Unhealthy | PM10 — coarse dust (PM10) |
| 7 | (2024 page) | 171 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 8 | (2024 page) | 169 | Unhealthy | PM10 — coarse dust (PM10) |
| 9 | (2025 page) | 162 | Unhealthy | PM10 — coarse dust (PM10) |
| 10 | (2021 page) | 148 | Unhealthy for Sensitive Groups | PM10 — coarse dust (PM10) |
Worst day of each year in Tucson
The single highest-AQI day in each year on record. Click a year for its full month-by-month statistics.
| Year | Worst day | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 2019 | 103 | Unhealthy for Sensitive Groups | PM10 — coarse dust (PM10) | |
| 2020 | 277 | Very Unhealthy | PM10 — coarse dust (PM10) | |
| 2021 | 313 | Hazardous | PM10 — coarse dust (PM10) | |
| 2022 | 142 | Unhealthy for Sensitive Groups | PM10 — coarse dust (PM10) | |
| 2023 | 147 | Unhealthy for Sensitive Groups | PM10 — coarse dust (PM10) | |
| 2024 | 171 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2025 | 357 | Hazardous | PM10 — coarse dust (PM10) |
Tucson's 10 best air quality days, 2019–2025
Lowest daily AQI recorded for the Tucson, AZ area. Ties are listed most recent first.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2019 page) | 23 | Good | O3 — ground-level ozone |
| 2 | (2020 page) | 25 | Good | O3 — ground-level ozone |
| 3 | (2019 page) | 28 | Good | O3 — ground-level ozone |
| 4 | (2019 page) | 29 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 5 | (2025 page) | 31 | Good | O3 — ground-level ozone |
| 6 | (2024 page) | 31 | Good | O3 — ground-level ozone |
| 7 | (2022 page) | 31 | Good | O3 — ground-level ozone, in peak ozone season |
| 8 | (2019 page) | 31 | Good | O3 — ground-level ozone |
| 9 | (2019 page) | 31 | Good | PM10 — coarse dust (PM10) |
| 10 | (2019 page) | 31 | Good | O3 — ground-level ozone |
Right now in Tucson
The latest EPA AirNow observation puts Tucson's AQI at 35 (O3). The days above are historical records, not today's reading.
View current Tucson air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Tucson, 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.