Estimation of on-road NO2 concentrations, NO2/NOX ratios, and related roadway gradients from near-road monitoring data.

摘要: This paper describes a new regression modeling approach to estimate on-road nitrogen dioxide (NO2) and oxides of (NOX) concentrations near-road spatial gradients using data from monitoring network. Field were collected in Las Vegas, NV, at three monitors sited 20, 100, 300 m Interstate-15 between December 2008 January 2010. Measurements NO2 NOX integrated over 1-h intervals matched with meteorological data. Several mathematical transformations tested for regressing pollutant against distance the roadway. A logit-ln model was found have best fit (R 2 = 94.7 %) also provided physically realistic profile. The used gradient which mobile source pollutants elevated above background levels. Average maximum concentration estimates 33 105 ppb, respectively. Concentration steeper morning late afternoon compared overnight when stable conditions preclude mixing. Estimated highest afternoon. Median estimated lower during summer winter, summer, convective mixing occurs longer portion day. On-road higher winds perpendicular road parallel atmospheric stability neutral-to-unstable conditions. increasing be sharper wind winds. NO2/NOX ratios yielded ranging 0.25 0.35, substantially than anticipated tailpipe emissions ratios. results showed that diurnal cycle driving factor downwind