Abstract:
The hourly data from environmental monitoring stations in Shandong province during 2013-2021 was used to characterize six pollutants, to explore the temporal and spatial distributions of particulate matter (PM) and ozone (O
3), and to analyze the meteorological conditions and sources of pollution. The results show that the air quality in Shandong province has improved year by year from 2013 to 2021. The annual mean mass concentration of PM
2.5 in 2021 decreased by 60.2% compared to that in 2013. The annual mean concentration of O
3 shows a rising trend year by year during 2013-2021, while the concentrations of the other five pollutants decrease. PM and O
3 are the most important pollutants affecting the air quality in Shandong province. CO, NO
2, PM
10, PM
2.5, and SO
2 concentrations exhibit a unimodal pattern characterized by highs in winter and lows in summer; O
3 concentrations show a unimodal pattern feature with the highest in summer and the lowest in winter. The spatial distribution is characterized by high pollutant concentrations in the central and western part of Shandong province and low concentrations in the eastern part of Shandong province. Environmental meteorological index and atmospheric self-purification capacity index characteristics show that the combination of favorable meteorological conditions and emission reduction during 2013-2021 led to a 59 μg·m
-3 decrease in the annual average concentration of PM
2.5 in 2021 compared to that in 2013, with emission reduction as the main reason. Source apportionment shows that the proportion of PM
2.5 from local emissions is high in most areas of Shandong province. The share of local emissions decreased in 2021 compared to that in 2019. An area is closer to Hebei and He'nan provinces, the share of exogenous transmission is the larger. Local emissions in the seven corridor cities accounted for 31%~54% in 2019, and 19%~34% in 2021, with northwest Shandong province being the most affected by external transport.