placestats

Days with an air quality reading

How many days of the year the county's air monitors gave an Air Quality Index reading. It shows how well the county's air is watched, not how clean it is. Counties with no monitor are missing. Years with fewer than 274 days are left out of the air measures, since part of a year can't be compared with a whole one.

Reported for803areas, in 51 states — none in CT
Link to density0.20not mostly about how urban a place is
Nearby places alike0.08Moran’s I: only weakly, little map pattern
Typeratedays

How it has moved

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Every state, every year

Nothing to draw here: this measure has no state figures. Its publisher reports it for counties. This site does not add county numbers up into state figures, since a home-made figure could clash with one an agency publishes itself. The chart above covers the whole country, year by year.

Where it comes from

EPA Air Quality System · EPA AQS annual_aqi_by_county, Days with AQI

How many days of the year the county's monitors produced an AQI. It measures monitoring, not air. Adding days across counties counts county-days, which is not a number of days.

Combining areas: it cannot be combined, so it is shown only where its publisher works it out.

Population makeup

How this measure varies with the racial and ethnic makeup of counties. Every group is shown, whatever its rank. These are links across counties: they describe places, not people. They say nothing about any person’s risk or behaviour based on their race. Counties with a larger share of one group also differ in much else, such as income, segregation, region and history. The adjusted figure only accounts for density, income and education.

Share of residentsUnadjustedAdjusted
Days with an air quality reading and Share White, not HispanicCould easily be chance once only places with similar density, income and education are compared. Share White, not Hispanic by US county-0.07-0.05
Days with an air quality reading and Share Black, not HispanicCould easily be chance once only places with similar density, income and education are compared. Share Black, not Hispanic by US county+0.05+0.03
Days with an air quality reading and Share Hispanic or Latino, any raceCould easily be chance once only places with similar density, income and education are compared. Share Hispanic or Latino, any race by US county+0.01+0.00
Days with an air quality reading and Share Asian, not HispanicCould easily be chance once only places with similar density, income and education are compared. Share Asian, not Hispanic by US county+0.13+0.07
Days with an air quality reading and Share American Indian or Alaska Native, not HispanicCould easily be chance once only places with similar density, income and education are compared. Share American Indian or Alaska Native, not Hispanic by US county-0.09-0.05

Highest and lowest

Of 803 counties reporting it. These are the two ends of a national ranking. For most measures, that ranking mostly sorts places by income and how urban they are. That is why the place pages compare each place with similar places instead.

Highest

  1. Weld County, CO — 365
  2. Rio Blanco County, CO — 365
  3. Montezuma County, CO — 365
  4. Mesa County, CO — 365
  5. Larimer County, CO — 365

Lowest

  1. Aiken County, SC — 275
  2. Berkeley County, WV — 277
  3. Monongalia County, WV — 277
  4. Haywood County, NC — 278
  5. Canadian County, OK — 278

The middle area reports 365. The middle half of counties falls between 360 and 365 (the 25th to 75th percentile).

US Counties With the Highest Days with an Air Quality Reading · US Counties With the Lowest Days with an Air Quality Reading

All measures · Explore its pairs · How the US county data works