Table 1. National and Florida ambient air quality standards^; ug/m3 

 microgram per cubic meter (Florida State Department of Environmental 

 Regulation, Bureau of Air Quality Management 1980). 



The air quality standards and a description of the Federal Reference Methods 

 (FRM) were published on April 30, 1971, in 42 CFR 410, recodified to 40 CFR 

 50 on November 25, 1972. The new FRM for nitrogen dioxide was published on 

 December 1, 1976, as 40 CFR 50. 



Not to be exceeded more than once a year. 



Geometric mean is a measure of central tendency. It is the nth root of the 

 product of n individual data values recorded during the given period. 



Arithmetic mean is the most common measure of the central tendency. It is 

 the sum of the data collected during the given period divided by the number 

 of observations in the same period. 

 Parts per million. 



Chemiluminescence has been established as the FRM and the sodium arsenite and 

 trienthanolamine guiacol sulfite (TGS) methods have been identified as equiv- 

 alent methods. 



^The FRM measures 0, (ozone). 



The hydrocarbon HC standard is a guide to devising State implementation plans 

 to achieve the oxidant standard. The HC standard does not have to he met if 

 the oxidant standard is met. 



257 



