Air Quality Blog
Data-driven analysis of air quality trends across America, powered by EPA monitoring data.
April 6, 2026
Is It Safe to Run Outside? AQI Guide for Runners
AQI thresholds for outdoor exercise, best time of day to run, and city rankings for athletes — backed by EPA monitoring data.
April 6, 2026
Best Cities for People with Asthma
The best US cities for asthma sufferers, ranked by unhealthy air days, average AQI, and trend direction using 10 years of EPA data.
April 6, 2026
How Wildfires Changed Air Quality in America
Wildfire smoke has reversed decades of air quality progress in western cities. Data reveals which areas are most affected and how far smoke travels.
April 6, 2026
Air Quality Before and After COVID Lockdowns
Did COVID lockdowns improve air quality? EPA data for 1,000+ cities reveals which areas saw the biggest drops — and whether improvements lasted.
April 6, 2026
Fastest-Improving Air Quality Cities in America
These US cities have the biggest AQI improvements over the past decade. EPA data reveals where air quality is getting better the fastest.
April 6, 2026
PM2.5 Trends: Which Cities Are Getting Worse?
PM2.5 fine particulate matter is rising in dozens of US cities. EPA data reveals where levels are increasing, driven by wildfires and industry.
April 5, 2026
Cities Where Air Quality Is Getting Worse
These US cities have seen the biggest increases in AQI over the past decade. Data shows which areas are declining — and why.
April 5, 2026
Best Cities for Air Quality in 2026
The top 20 US cities ranked by air quality using EPA data and Air Quality Grades. See which cities earned an A grade.
April 5, 2026
What Is a Good AQI Score? Ranges Explained
The Air Quality Index ranges from 0-500. A good AQI score is 0-50. Learn what each range means for your health with real city examples.