What Is the Air Quality in Valley, Idaho?

Valley, Idaho earns a D — air quality falls below the U.S. average, with a 5-year median AQI of 37. Residents with asthma, COPD, heart disease, or young children should watch daily AQI forecasts and limit outdoor exertion when alerts go out.

Valley, Idaho's 5-year median AQI of 37 is 4 points below the national average of 41 — meaningfully cleaner than the typical U.S. metro tracked here. Within Idaho, Valley, Idaho runs more polluted than the state average of 33 — local sources or geography are concentrating pollution above the state's typical reading.

For context within Idaho: Custer, Idaho currently holds the state's cleanest grade (A, AQI 8), while Canyon, Idaho sits at the bottom (C, AQI 41).

Air quality in Valley, Idaho has been getting worse over the past decade, with median AQI climbing by roughly 2.8 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 2015, Valley, Idaho posted a median AQI of 18. By 2023 that figure was 36 — a rise of 18 AQI points dirtier across 9 years of EPA records.

Across the past five years, this area has logged just 24 days where AQI rose into the "Unhealthy for Sensitive Groups" range or worse — about 5 days per year, or roughly one every other month. That is a low count by national standards.

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 PM2.5 penetrates deep into the lungs and bloodstream, an N95 or KN95 mask provides meaningful protection on smoky or high-particulate days — surgical masks do not.