Utilizing a state-of-the-art mobile laboratory in conjunction with a dynamic flow-through chamber system, nitric
oxide concentrations [NO] were measured and NO fluxes were calculated during the summer, winter and spring of 1999/
2000. The field site where these measurements were conducted was an agricultural soil amended with biosolids from a
municipal wastewater treatment facility. These NO flux values were then used to assess the impact of including biosolid
amended soils as a land-use class in an air quality model. The average NO flux from this biosolid amended soil was
found to be exponentially dependent on soil temperature [NO Flux ðng N m2 s1Þ ¼ 1:07 expð0:14 TsoilÞ; R2 ¼ 0:81—
NO Flux ¼ 71:3 ng N m2 s1 at 301C]. Comparing this relationship to results of the widely applied biogenic
emissions inventory system (BEIS2) model revealed that for this field site, if the BEIS2 model was used, the NO
emissions would have been underestimated by a factor of 26. Using this newly developed NO flux algorithm, combined
with North Carolina Division of Water Quality statistics on how many biosolid amended acres are permitted per
county, county-based NO inventories from these biosolid amended soils were calculated. Results from this study
indicate that county-level biogenic NO emissions can increase by as much as 18% when biosolid amended soils are
included as a land-use class. The multiscale air quality simulation platform (MAQSIP) was then used to determine
differences in ozone ðO3) and odd-reactive nitrogen compounds ðNOyÞ between models run with and without the
biosolid amended acreages included in the inventory. Results showed that during the daytime, when atmospheric
mixing heights are typically at their greatest, any increase in O3 or NOy concentrations predicted by the model were
small ðo3%Þ: In some locations during late evening/early morning hours, ozone was found to be consumed by as much
as 11%.
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