A high resolution Volatile Organic Compounds Emission from gas station and its effect on ozone concentration: take Xi’an for example

The contribution of volatile organic compounds (VOC) to ozone continues to receive attention and various localities have successively introduced measures to control VOC including limiting emissions from gas stations. Xi’an, as a major city of Fenwei Plain, has a large number of motor vehicles and a large demand for gasoline, and the VOC emission from gas stations can not be ignored in the city. In order to understand its impact on ozone and provide a reasonable basis for gas stations control and governance, this paper combines the SMOKE model to construct a gridded Xi’an gas stations VOC emissions, and uses WRF-CAMx model to study its effect on ozone concentration in summer. The results show that: (1) After considering the VOC emissions from gas stations, the concentrations of ozone (O 3 ) and secondary organic aerosol (SOA) simulated by the sensitivity test in July 2018 were slightly higher than that results without the gas stations VOC emissions. (2) Similar to the baseline scenario, the daily change of O 3 in July 2018 simulated by the control test considering gas stations VOC emissions shows a unimodal distribution; the diurnal change of secondary organic aerosol (SOA) is characterized by a high concentration in the morning even a peak. While the overall concentration level decreased in the afternoon, and gradually increased in the evening. (3) The results of sensitivity numerical test show that the gas stations VOC emissions in Xi’an just has a little influence on air quality, 63.5% hours its effect on ozone is within 0.01 μg/m³, and the VOC emissions from gas stations has different influence on ozone concentration in different hours. The maximum influence on hourly ozone concentration in Xi ’an is about 0.20 μg/m³.