Indicator · us-no2-days
Days when nitrogen dioxide set the AQI
Traffic and combustion; the pollutant with the highest AQI that day.
- Unit
- % of days
- Places
- 916 counties in 2025
- Built from
- Yearly air quality summary by county
Map and compare every county on visualizedata.org →
Median county, 1980–2025
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Show the data as a table
Highest and lowest in 2025
| Karnes County, TX | 100.0% of days |
|---|---|
| Wilson County, TX | 100.0% of days |
| Carbon County, WY | 88.7% of days |
| Macoupin County, IL | 34.1% of days |
| Hudson County, NJ | 28.5% of days |
| Yuma County, AZ | 0.0% of days |
|---|---|
| York County, SC | 0.0% of days |
| York County, ME | 0.0% of days |
| Yolo County, CA | 0.0% of days |
| Yavapai County, AZ | 0.0% of days |
779 counties share this value; five are shown, alphabetically.
How it is computed
EPA days NO2 was the main pollutant / days with an AQI, from the Yearly air quality summary by county dataset on this site. visualizedata.org computes the indicator for every place and year; the full table, the map and each place's history are on its page there. The underlying data, with its source and license, is on the dataset page, with the API and downloads.