| Abstrakt: |
Being a typical city of heavy industry in west China, Urumqi City is subjected to serious atmospheric ozone pollution in the urban areas due to rapid industrialization and urbanization development. In order to probe into the characteristics of the City' s land-surface ozone pollution, the monitoring data of air pollutants and the meteorological observation data from 2015 to 2019 were applied with the statistical analysis, backward trajectory analysis, potential source contribution factor (PSCF) and concentration weighted trajectory (CWT) to analyze the characteristics and potential source-areas of ozone pollution in Urumqi. The results showed (1) the annual evaluation index of ozone during the period (2015-2019) increased from 118 µg/m³ to 128 µg/m³, and at the same time, the main air pollutant in Urumqi has underwent a transition, i.e, from PM to ozone, the proportion of ozone as a primary pollutant up from 5.8% (2015) to 28.0% (2019). The ozone concentrations variation characteristics of seasons in order of decreasing magnitude: summer>spring>autumn>winter; on the interannual scale, ozone was negatively correlated to NO2 and CO obviously; (2) according to the backward trajectory analysis, the airflow that affected the distribution of atmospheric ozone in Urumqi was characterized by that passing from outbound areas, long-distance migration and containing high ozone concentration. The airflow migration path within the city territory was generally short, not very much influencing the transmission of ozone concentration in Urumqi; and (3) results of using PSCF and the concentration CWT showed that the main source-areas and high ozone-contribution areas that affected the ozone concentration in Urumqi were Changji Prefecture, Tacheng District, Bortala Mongolian Autonomous Prefecture and Altay District; and the distribution of ozone source-areas and high ozone-contribution areas was positively correlated to the seasonal variation of ozone concentrations, which had the evident seasonal characteristics, i.e., the potential source-areas in summer were mainly the moderate source-areas, which widely distributed within the city and had higher ozone contribution, while in winter the whole area of Urumqi turned into a mild source-area; as to spring and autumn the feature of the source-areas fell in between. [ABSTRACT FROM AUTHOR] |
