| In recent years,the haze weather characterized by particulate pollution has occurred frequently in northern cities of China.The analysis results of atmospheric particulate pollution sources in some cities indicate that the dust source is one of the main sources of urban particulate pollution.With the expansion of the urban road network and the continuous increase in the number of motor vehicles,road fugitive dust caused by traffic activities has become a major component of the dust source,and it is an important source of atmospheric particulate matter in urban agglomerations,which not only reduces urban air quality,but also affects people’s daily life and harms people’s health.Therefore,the study on the characteristics of road fugitive dust emission and the establishment of emission inventory can provide reference and data support for urban dust pollution control and atmospheric particulate pollution treatment.In this article,the vacuum cleaning method and rapid detection method were used to conduct on-site detection of the silt loading in Xi’an and Weinan in the Guanzhong urban agglomeration,and the AP-42 model recommended by the U.S.Environmental Protection Agency was used to estimate the annual emissions of road fugitive dust PM2.5,PM10and TSP in 2018 in the Guanzhong urban agglomeration by combining localized parameters such as traffic volume,vehicle type distribution,average vehicle weight,road length and precipitation days on different types of roads in various cities in the Guanzhong area.And analyze the road dust emission characteristics,temporal and spatial distribution characteristics,the impact on environmental particulates in the road area,and the dust control effect of starting different levels of emergency measures during heavy pollution.According to the research results,some suggestions were put forward to improve road dust control measures in Guanzhong urban agglomeration.The main research conclusions are as follows:（1）The average silt loading range of various types of roads in Guanzhong urban agglomeration was 0.05～2.13 g/m2,and the analysis of silt loading on roads around different functional areas in Weinan city showed that the average silt loading（1.77g/m2）on the roads driven by muck trucks was 58.04%higher than the average silt loading（1.12g/m2）on urban roads.The emission factors of PM2.5,PM10 and TSP in various types of road fugitive dust particles in Guanzhong were between 0.03～0.44,0.13～1.83 and 0.66～9.53 g/（km·veh）,respectively.The emission intensity ranges were 0.37～24.86,1.55～102.76 and 8.07～535.33kg/（km·d）,respectively.（2）The total annual emissions of road fugitive dust PM2.5,PM10 and TSP in Guanzhong urban agglomeration in 2018 were 6.42×104,26.52×104 and 138.15×104t respectively.And the emission sharing rate of cities in descending order was as follows:Xi’an（57.90%）,Weinan（14.87%）,Xianyang（14.02%）,Baoji（12.28%）and Tongchuan（0.93%）.Among the emission sharing rates of various roads,the dust emissions of spur tracks and minor roads accounted for a relatively large proportion（21.85%and 21.14%,respectively）,and county and township roads,national roads,provincial roads,major roads and expressways accounted for 19.19%,18.33%,9.4%,6.02%and 3.32%respectively,ring roads emissions accounted for the smallest percentage（0.75%）.The sharing rate of each vehicle type from high to low was as follows:small passenger cars（57.55%）,large passenger cars（24.61%）,heavy trucks（8.09%）,medium trucks（4.78%）,light trucks（2.24%）),low-speed vehicles（1.61%）,medium-sized passenger cars（1%）,motorcycles have the smallest emission sharing rate,accounting for only 0.11%.（3）The contribution of road fugitive dust emission from Guanzhong urban agglomeration to road environment PM2.5 and PM10 reached 93.87%and 96.96%respectively,motor vehicle exhaust contribution rate was 5.32%and 1.46%respectively,and the proportion of wear emissions was 0.81%and 1.58%,of which more than 80%of the wear emissions came from brake wear.（4）Taking Xi’an City as an example to evaluate the dust control effect of different levels of emission reduction measures launched during heavy pollution,it can be seen that the particulate reduction rate during the level Ⅲ emergency was in the range of 22.75%～51.18%,and the level Ⅱ reduction rate was in the range of 23.64%～81.54%,the level I reduction rate ranges from 58.36%to 90.08%,and the larger the particle size,the higher the reduction efficiency.The level Ⅱ and Ⅲ emission reduction measures have better dust suppression effects on the county and township road and expressway,the emergency emission reduction efficiency of level I was very high on the whole,which was about 2～3 times of that of grade Ⅱ and Ⅲ. |
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