Table 2.

Criteria pollutants.

Pollutant	Source	Averaging Time	Level
Carbon Monoxide	Traffic	8 hour 1 hour	9 ppm 35 ppm
Lead	Metal processing industries	Rolling 3 month average	0.15 μg/m3
Nitrogen Dioxide	High temperature combustion	1 hour Annual	100 ppb 53 ppb
Ozone	Sunlight on oxidants emitted by engines and industry	8 hour	0.075 ppm
Particulate Matter2.5	Combustion processes, smoke, haze	Annual 24 hour	15 μg/m3 35 μg/m3
Particulate Matter10	Dust, soil, crushing and grinding processes, near roadways	24 hour	150 μg/m3
Sulfur Dioxide	Industrial processes, especially coal	1 hour	75 ppb