NO to NO2 Conversion Rate Analysis and Implications for Dispersion Model Chemistry Methods using Las Vegas, Nevada Near-Road Field Measurements.

摘要: The nitrogen dioxide/oxides of (NO2/NOX) ratio is an important surrogate for NO to NO2 chemistry in dispersion models when estimating NOX impacts a near-road environment. Existing use different techniques and assumptions represent conversion do not fully characterize all the atmospheric chemical mechanical processes. Thus, "real-world" ambient measurements must be analyzed assess behavior NO2/NOX ratios near roadways. An examination data from field study conducted Las Vegas, Nevada (NV), mid-December, 2008 through 2009 provides insights into appropriateness about included models. Data analysis indicates multiple factors affect downwind ratio. These include spatial gradient, background ozone (O3), source emissions NO2, Analysis gradient that under high O3 conditions, change fairly constant once certain threshold (≥ 30 ppb) reached. However, low conditions (< ppb), there are differences between weekdays weekends, most likely due decline concentrations during weekday morning hours, reducing available titrate emitted NO, allowing lower ratios. results suggest driving whereas mixing factor.