Air quality standards | WELL Standard

01.2.a

The EPA’s 2012 NAAQS require ambient air in cities to keep 8-hr average levels of carbon monoxide below 9 ppm and 1-hr averages below 35 ppm, not to be exceeded more than once per year.

01.2.b

The EPA’s 2012 NAAQS requre PM₂.₅ to be less than 12 μg/m³ for a primary annual mean, secondary annual mean of 15 μg/m³ and a 24-hour concentration of 35 μg/m³, averaged over three years .

01.4.c

The EPA’s NAAQS for nitrogen dioxide set 100 ppb as the limit for the 98th percentile (averaged over three years) of hourly means.

01.4.a

The EPA’s NAAQS set a 1-hour concentration level for carbon monoxide at 35 ppm, which is not to be exceeded more than once a year.

01.4.b

The EPA’s NAAQS sets standards for PM₂.₅ at 12 μg/m³ for a primary annual mean, a secondary annual mean set at 15 μg/m³ and a 24-hour concentration set at 35 μg/m³, all averaged over three years.