About LocalAirData
Making air quality data accessible to every American — so you can make informed decisions about where you live, work, and play outdoors.
Why We Built This
Most people have no idea what the air quality is in their city — until there's a wildfire, a smog alert, or a family member with asthma who can't breathe. At that point, the data that exists is either buried in EPA databases or presented in ways that require a science degree to parse.
We built LocalAirData to fix that. Our goal is simple: give every American an honest, easy-to-understand picture of the air they breathe — whether they're checking their own city, comparing places before a move, or figuring out which days are safe to run outside.
The data is all public. The EPA collects it. We just make it useful.
Our Mission
Air quality directly affects millions of Americans every day — from chronic health conditions to deciding whether to let kids play outside. Yet that data is often buried in government databases, hard to find, and harder to understand.
LocalAirData brings together real-time AQI readings, historical pollution trends, and clear health guidance for every US city and ZIP code. We translate raw data into simple grades and actionable recommendations.
Our Data Sources
AirNow API (Real-Time)
Current AQI readings come from the AirNow API, operated by the U.S. EPA in partnership with NOAA and National Park Service. Readings are refreshed hourly from thousands of monitoring stations nationwide.
EPA Air Quality System (Historical)
Historical annual AQI data comes from the EPA's Air Quality System (AQS) database, which tracks daily and annual measurements going back decades. We use county-level data to calculate multi-year trends.
US Census / Geographic Data
City, county, and ZIP code geographic data comes from US Census Bureau sources, ensuring accurate location matching for air quality readings.
How We Calculate Air Quality Grades
Our letter grades (A+ through F) are based on a city's median AQI from EPA annual data. The median AQI represents the middle value of all days measured — a better indicator of typical air quality than averages skewed by extreme events.
| Grade | Median AQI Range | Description |
|---|---|---|
| A+ | 0–30 | Excellent air quality |
| A | 31–40 | Very good air quality |
| A– | 41–50 | Good air quality |
| B+ | 51–60 | Above average |
| B | 61–70 | Average air quality |
| C | 71–100 | Fair, some concern |
| D | 101–150 | Poor air quality |
| F | 150+ | Very poor air quality |
Quick Facts
- •Coverage across all 50 US states
- •Real-time AQI updated hourly
- •Historical data going back 10+ years
- •6 EPA criteria pollutants tracked
- •ZIP code-level data available