|
Description:
|
Some of the air pollution regulations in the United States are based on an
application of the National Ambient Air Quality Standards at the property line .
Agricultural operations such as cotton gins , feed mills , and cattle feed yards may be
inappropriately regulated by such regulations if the current methods of measuring and
predicting the concentrations of regulated pollutants are used . The regulated particulate
matter pollutants are those with aerodynamic equivalent diameters less than or equal to a
nominal 10 and 2 .5 micrometers (PM10 and PM2 .5 ) respectively .
The current Federal Reference Method PM10 and PM2 .5 samplers exhibit oversampling
errors when sampling dusts with particle size distributions similar to those of
agricultural sources . These errors are due to the interaction of the performance
characteristics of the sampler with the particle size distribution of the dust being
sampled . The results of this work demonstrate the development of a new sampler that
may be used to accurately sample total suspended particulate (TSP ) concentrations . The
particle size distribution of TSP samples can be obtained and used to more accurately
determine PM10 and PM2 .5 concentrations . The results of this work indicate that accurate
measures of TSP can be taken on a low volume basis . This work also shows that the low
volume samplers provide advantages in maintaining more consistent sampling flow
rates , and more robust measurements of TSP concentrations in high dust concentrations .
The EPA approved dispersion model most commonly used to estimate
concentrations downwind from a stationary source is the Industrial Source Complex
Short Term version 3 (ISCST3 ) . ISCST3 is known to over -predict downwind
concentrations from low level point sources . The results of this research show that the
magnitude of these errors could be as much as 250 % . A new approach to correcting
these errors using the power law with P values as a function of stability class and
downwind distance is demonstrated . Correcting the results of ISCST3 using this new
approach results in an average estimated concentration reduction factor of 2 .3 . |