Air Quality Field Measurements in Las Vegas: Ozone Formation and Its Sensitivity to NO _x and VOCs

Abstract Las Vegas, Nevada is an urban center in the southwest US where the population is rapidly growing. In Las Vegas, surrounded by the Mojave Desert, biogenic emissions are low, but anthropogenic emissions, especially along the Las Vegas Strip, are a large source of volatile organic compounds (VOC) and nitrogen oxides (NO + NO 2 = NO x ) from volatile chemical products, cooking, and fossil fuel usage. This makes Las Vegas an ideal place to study anthropogenic VOC emissions and oxidation in the absence of a strong biogenic signal. The urban air quality in Las Vegas was measured at a stationary site and with a mobile laboratory. Biogenic VOC influence, VOC enhancement ratios, and weekday‐weekend effects were evaluated. An Eulerian box model was constructed to evaluate the chemical processes impacting air quality in Las Vegas. The model showed that the daily ozone (O 3 ) enhancement, taken as the maximum O 3 produced midday above background, was approximately 30 ppb. The O 3 sensitivities to VOCs and NO x showed that reductions in both would reduce O 3 production. Reducing NO x or VOCs by half would reduce O 3 by 10.5 and 11.5 ppb, respectively. Reducing both NO x and VOCs together would decrease O 3 by 15 ppb. The O 3 contribution from biogenic VOCs was ∼3.5 ppb, which is about 10% of the total produced O 3 . This differs from other regions of the US, such as New York or Los Angeles, where biogenic VOCs contribute significantly to urban ozone.