The purpose of 310 CMR 8.00 is to prevent ambient air contaminantconcentrations atanylocation in the Commonwealth from reaching levels which would constitute significant harm, or imminent and substantial endangerment to the health of persons. The levels which would constitute significant harm, or imminent and substantial endangerment, to the health of persons as have been defined by the Administrator of the Environmental Protection Agency are set forth in Table 1.

TABLE 1.

CONTAMINANT CONCENTRATION LEVELS

Prescribed by the EPA Administrator as would cause significant harm, or Imminent and Substantial Endangerment, to Health. W444444444444444444444444444444444444444444444444444444444444444

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Ambient Air Contaminant Concentration Levels

Contaminant Ave. ug/m 3 ppm COHs Duration Product

(average)

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Sulfur Dioxide (SO ) 2 2,620 1.0 24-hr.

Particulate Matter PM10 600 24-hr. Tape Stain (COHs) 8 24-hr.

Product of: (SO ) X (COHs) (SO ) 2 2 (COHs) 24-hr. 1.5

Carbon Monoxide 144,000 125 1-hr.

Carbon Monoxide 86,300 75 4-hr.

Carbon Monoxide 57,500 50 8-hr.

Photochemical Oxidant 1,200 0.6* 1-hr.

Nitrogen Dioxide 3,750 2.0 1-hr.

Nitrogen Dioxide 938 0.5 24-hr.

*expressed as Ozone (O ) 3