THESIS
2022
1 online resource (69 pages) : illustrations (chiefly color), color maps
Abstract
China’s air pollution has been effectively controlled in recent years. However, in some
major city clusters with fast growing economies and large population density, air quality
is still far below the world recommended health standards. Chongqing is the largest
municipality located in southwestern China. The well-developed industrial economy
and the highly dense population here result in a large number of anthropogenic
emissions of air pollutants, combined with its complex geography and stable
meteorological conditions, continuously causing server air pollution. While research
has been done focusing on air pollution in other major city clusters, relatively less
research has been done on air pollution in Chongqing. Not to mention further study the
effects of urban morphology on local pol...[
Read more ]
China’s air pollution has been effectively controlled in recent years. However, in some
major city clusters with fast growing economies and large population density, air quality
is still far below the world recommended health standards. Chongqing is the largest
municipality located in southwestern China. The well-developed industrial economy
and the highly dense population here result in a large number of anthropogenic
emissions of air pollutants, combined with its complex geography and stable
meteorological conditions, continuously causing server air pollution. While research
has been done focusing on air pollution in other major city clusters, relatively less
research has been done on air pollution in Chongqing. Not to mention further study the
effects of urban morphology on local pollutant dispersion using fine-scale air quality
models. In such a case, this study first establishes a coupled air quality model called
WRF-CMAQ-ADMS, then uses the model to study Chongqing’s air pollutant
distribution pattern in January and April 2022. It is found that at the morning traffic
peak and at night, the central city of Chongqing has high spots of NO
2 and particulate
matter, along with other high concentration spots near the airport, power plant, and
industries area. Over half a month of days with PM
2.5 concentration exceeded air
quality standards, which should draw more government and public attention. This study
also conducted a sensitive experiment on how urban buildings affect pollutant concentrations and found that the street canyon effect can increase NO
2 and PM
2.5 by
up to 8 μg/m³and 7 μg/m³, respectively, and up to 8% and 12% after doubling the
building height for NO
2 and PM
2.5. In the vertical direction, there is a change in the
NO
2 concentration layer every 40 meters on average. As the height increases, the
pollutant concentration decreases, while PM
2.5 has less change in the concentration
layer at the same height. However, people living in tall buildings on roadsides are more
likely affected by high ozone concentrations than ground-level people. Road
intersections and roads where buildings are close to the street are more significantly
affected by the street canyon effect.
Post a Comment