A high resolution Volatile Organic Compounds Emission from gas station
and its effect on ozone concentration: take Xi’an for example
Abstract
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 (O3) 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
O3 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.