In 1987, the EPA began using a standard (40 CFR 50.6) for concentrations of airborne particulate matter less than 10 micrometers in diameter (PM₁₀).  Particles of this size can reach the lungs and are considered to be responsible for most of the adverse health effects associated with airborne particulate pollution. 

ESER Program personnel operate three PM₁₀ samplers, one at Rexburg CMS, one at Blackfoot CMS, and one at Atomic City.  A sample was collected for a period of 24 hours, once every six days.  This interval yields 15 samples per location, per quarter.  However due to equipment failures, insufficient run time (24 hrs ± 1 hour), and/or filter problems, several samples were invalid during the 3^rd quarter including three from the Blackfoot CMS location (July 11, July 17, and September 21) and five samples from the Rexburg CMS location (July 5, August 16, August 22, August 4, and September 21).  The average, maximum, and minimum results of the 24-hour samples are shown in Table 3.  Results for all PM₁₀ samples are listed in Table C-5, Appendix C. 

The air quality standards for PM₁₀ are an annual average of 50 µg/m³, with a maximum 24-hour concentration of 150 µg/m³.  PM₁₀ concentrations for the third quarter of 2001 were well below all air quality standard levels.  The maximum 24-hour concentration was 47.1 µg/m³ on July 5, in Atomic City.   

TABLE 3.            Summary of 24-hour PM₁₀ Values (µg/m³) for each station.   

Air quality PM₁₀ standards permit an annual average of 50 µg/m³, and a maximum 24-hour concentration of 150 µg/m³.

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