Fujian Province highway motor vehicle pollutant emission inventory under the background of the COVID-19

ABSTRACT

Pollutants emitted from motor vehicles have become an important source of air pollution. Based on the traffic flow data of the expressways in Fujian Province, a high-resolution pollutant emission inventory of the expressways from January to July in 2020 was established by the bottom-up calculation method. The results show that under the influence of the COVID-19, the monthly average traffic flow and pollutant emissions of the expressways in Fujian province decreased firstly and then increased. Pollutant emissions reached the lowest in April, and quickly recovered to the pre-COVID-19 emission level in May. The pollutant emissions of the CO, HC, NOx, PM2.5 and PM10 in the middle stage of the COVID-19 decreased by 90.68%, 89.06%, 92.58%, 89.58% and 89.63%, respectively, compared with those in the post stage of the COVID-19. In the entire study period, different cities have different sharing rates of the pollutant emissions from motor vehicles, with Quanzhou, Fuzhou and Zhangzhou having higher motor vehicle emission sharing rates on the expressways. In terms of the vehicle types, the small passenger buses and the light trucks are the main contributors for CO and HC, and the heavy trucks and the light trucks are the main contributors for NOx and PM. In terms of the fuel types, the gasoline vehicle is the main source of CO and HC, and the diesel vehicle is the main source of NOx and PM. In terms of the emission standards, vehicles with China 3 and China 4 have the largest contribution rate to various pollutants. However, the spatial distribution of various pollutants is consistent, with the higher level emissions in the eastern coastal expressways, while the lower level emissions in the western inland expressways. From the spatial distribution of NOx emission intensity of Expressways in Fujian Province, the emission intensity of each section in March and April was at a very low level. Taking the main emission of the motor vehicle NOx as a case, the Shenyang-Haikou Expressway section has the highest NOx emission intensity. Moreover, the Xiamen and Quanzhou sections of Shenyang-Haikou Expressway have relatively high exposure levels of motor vehicle pollution, while other sections have relatively low exposure levels. © 2022, Science Press. All right reserved.