In the case of sulfur oxide and particulate matter, each applicable implementation plan shall contain measures assuring that maximum allowable increases over baseline concentrations of, and maximum allowable concentrations of, such pollutant shall not be exceeded. In the case of any maximum allowable increase (except an allowable increase specified under section 7475(d)(2)(C)(iv) of this title) for a pollutant based on concentrations permitted under national ambient air quality standards for any period other than an annual period, such regulations shall permit such maximum allowable increase to be exceeded during one such period per year.
Pollutant

Maximum allowable increase (in micrograms per cubic meter) 

Particulate matter: 

Annual geometric mean 
5 
Twentyfourhour maximum 
10 
Sulfur dioxide: 

Annual arithmetic mean 
2 
Twentyfourhour maximum 
5 
Threehour maximum 
25 
Pollutant

Maximum allowable increase (in micrograms per cubic meter) 

Particulate matter: 

Annual geometric mean 
19 
Twentyfourhour maximum 
37 
Sulfur dioxide: 

Annual arithmetic mean 
20 
Twentyfourhour maximum 
91 
Threehour maximum 
512 
Pollutant

Maximum allowable increase (in micrograms per cubic meter) 

Particulate matter: 

Annual geometric mean 
37 
Twentyfourhour maximum 
75 
Sulfur dioxide: 

Annual arithmetic mean 
40 
Twentyfourhour maximum 
182 
Threehour maximum 
700 