St. Johns, Arizona Air Quality
St. Johns has a median AQI of 14, earning an air quality grade of A+ — excellent air quality that ranks better than 96% of US cities. Air quality has remained relatively stable over the past decade. Particulate matter (PM10) is the primary concern, often linked to vehicle traffic, industrial activity, and wildfire smoke. In 2025, St. Johns recorded 269 good air quality days (100% of monitored days).
Population: 3,395 • County: Apache
Current AQI
Quick Facts
| Current AQI | 19 — Good |
| Air Quality Grade | A+ |
| Median AQI (2025) | 14 |
| vs. U.S. Cities | Better than 96% |
| Primary Pollutant | PM10 |
| Unhealthy Days/Year | 0 |
| 10-Year Trend | → Stable |
| Data Source | EPA AQS (historical) · AirNow (live) |
Health Recommendation
Air quality is satisfactory, and air pollution poses little or no risk.
It's a great day to be active outside!
5-Day AQI Forecast
Last 90 Days
Current Pollutant Levels
Real-time data from EPA AirNow
Local Air Quality Context
Air quality data for St. Johns is sourced from the Miami Golf Course monitoring area, located approximately 112 miles from city center. This EPA-certified station continuously tracks particulate matter (PM10), the primary driver of air quality alerts in this area.
Wildfire smoke is a significant factor in St. Johns's air quality, with regional fires capable of pushing AQI from Good to Unhealthy within hours during fire season (typically July through October). On smoke-impacted days, staying indoors with windows closed and running an air purifier with a HEPA filter is the most effective protection.
AQI Trend (10 Years)
Air Quality Days by Year
St. Johns Median AQI by Year
Annual EPA air quality data for St. Johns — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 14 | 269 | — | 52 | PM10 |
| 2024 | 14 | 350 | — | 57 | PM10 |
| 2023 | 13 | 362 | 1 | 106 | PM10 |
| 2022 | 11 | 359 | — | 57 | PM10 |
| 2021 | 15 | 353 | — | 90 | PM10 |
| 2020 | 14 | 356 | — | 63 | PM10 |
| 2019 | 11 | 357 | — | 64 | PM10 |
| 2018 | 13 | 354 | — | 58 | PM10 |
| 2017 | 14 | 361 | — | 62 | PM10 |
| 2016 | 14 | 362 | — | 56 | PM10 |
Source: EPA Air Quality System (AQS) annual summaries. "Unhealthy Days" includes Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, and Hazardous categories.
2025 Air Quality Summary
Primary Pollutant Days (2025)
Days when each pollutant was the primary driver of AQI. Learn about pollutants →
Frequently Asked Questions About St. Johns Air Quality
What is the air quality in St. Johns today?
The current AQI in St. Johns is 19, rated "Good". Air quality is good — outdoor activity is safe for everyone today. Air quality is satisfactory, and air pollution poses little or no risk.
Is air quality in St. Johns getting better or worse?
Air quality in St. Johns has been stable. The median AQI has remained stable at around 14 over the past decade.
What is the most common air pollutant in St. Johns?
PM10 is the primary air pollutant in St. Johns, responsible for 270 days (100% of monitored days) in 2025. Particulate matter originates from vehicle exhaust, wildfires, construction, and industrial activity.
How many unhealthy air days does St. Johns have per year?
In 2025, St. Johns recorded 100% good air quality days (269 days) out of 270 monitored days. There were 0 Unhealthy for Sensitive Groups days and 0 Unhealthy days (AQI above 100). The highest single-day AQI recorded was 52.
What air quality grade does St. Johns receive?
St. Johns receives an air quality grade of A+, placing it better than 96% of US cities. This is based on a median AQI of 14 in 2025, with 269 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 96% of US cities
Nearby Cities
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National Rankings
See how St. Johns compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for St. Johns
St. Johns's primary pollutant is PM10 (coarse dust and pollen). Units with a washable pre-filter stage plus True HEPA handle the larger particles that drive most of this area's air quality days.
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