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Seasonal and diurnal analysis of NO2 concentrations from a long-duration study conducted in Las Vegas, Nevada
Citation:
Kimbrough, Sue, R. Baldauf, AND N. Watkins. Seasonal and diurnal analysis of NO2 concentrations from a long-duration study conducted in Las Vegas, Nevada. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION. Taylor and Francis, Philadelphia, PA, 63(8):934-942, (2013).
Impact/Purpose:
Long-term monitoring in a near-road environment in Las Vegas, Nevada showed that pollutant concentrations are highest at distances closest to the highway. While high traffic volumes impact pollutant concentrations, meteorological conditions are important factors when assessing the impacts of emissions of highway vehicles in a near-road environment. For example, concentration gradients are observed during all wind conditions but are more pronounced under downwind conditions (i.e., winds from highway). Other important factors may include atmospheric temperature, atmospheric mixing, etc.
Description:
A study, conducted in Las Vegas, NV from mid-December 2008 to mid-December 2009 along an interstate highway, collected continuous and integrated ambient air quality samples for a wide variety of species including NO2 and NOX. Previous near-road studies have been short duration, a few weeks or months. This study provided a unique opportunity to examine long-term trends of NO2 and NOX ambient air quality measurements in a near-road environment. Study results indicate that concentration gradients are observed for NO2 and NOX with highest absolute and average concentrations at distances closest to the roadway. Higher traffic volumes impact pollutant concentrations although the effects of wind speed and wind direction are factors with regards to elevated pollutant concentrations and concentration gradients. Moreover, changes in ambient temperature may be a factor as well with regards to driving atmospheric chemistry activity. These concentration gradients are observed for all wind conditions; however under downwind conditions (winds from highway), the concentration gradients are more pronounced. Higher pollutant concentrations are generally observed during low wind speed conditions especially when those winds were from the highway. Assessing the variability and levels of pollutant concentrations in the near-road environment is important for evaluating potential exposures and assessing risks for near-road populations.
