Section 243.122  Sulfur Oxides (Sulfur Dioxide)

a)         Primary Standards.  The primary ambient air quality standards for sulfur oxides measured as sulfur dioxide are:

1)         An annual arithmetic mean concentration of 80 micrograms per cubic meter (0.03 ppm); and,

2)         A maximum 24-hour concentration not to be exceeded more than once per year of 365 micrograms per cubic meter (0.14 ppm).

b)         Secondary Standard.  The secondary ambient air quality standard for sulfur oxides measured as sulfur dioxide is a maximum 3-hour concentration not to be exceeded more than once per year of 1,300 micorgrams per cubic meter (0.5 ppm).

c)         Measurement Method.  For determining conformance with sulfur oxide air quality standards, sulfur oxides shall be measured as sulfur dioxide by the pararosaniline method described in 40 CFR 50, App. A, (1982), or by an equivalent method of proof approved by the Agency.