Analysis of Spatial-Temporal Characteristics of the PM2.5 Concentrations in Weifang City, China

Abstract

Air pollution, which accompanies industrial progression and urbanization, has become an urgent issue to address in contemporary society. As a result, our understanding and continued study of the spatial-temporal characteristics of a major pollutant, defined as 2.5-micron or less particulate matter (PM2.5), as well as the development of related approaches to improve the environment, has become vital. This paper studies the characteristics of yearly, quarterly, monthly, daily, and hourly PM2.5 concentrations, and discusses the influencing factors based on the hourly data of nationally controlled and provincially controlled monitoring stations, from 2012 to 2016, in Weifang City. The main conclusion of this study is that the annual PM2.5 concentrations reached a peak in 2013. With efficient aid from the government, this value has decreased annually and has high spatial characteristics in the northwest and low spatial characteristics in the southeast. Second, the seasonal and monthly PM2.5 concentrations form a U-shaped trend, meaning that the concentration is high in the summer and low in the winter. These trends are highly relevant to the factors of plantation, humidity, temperature, and precipitation. Third, within a week, higher PM2.5 concentrations appear on Mondays and Saturdays, whereas the lowest concentration occurs on Wednesdays. It can be inferred that PM2.5 concentrations tend to be highly dependent on human activities and living habits. Lastly, there are hourly discrepancies within the peaks and troughs depending on the month, and the overall daytime PM2.5 concentrations and reductive rates are higher in the daytime than in the nighttime.

Transport Pathways and Potential Source Region Contributions of PM2.5 in Weifang: Seasonal Variations

“…The data were acquired from the Data Center of the Ministry of Environmental Protection of the People's Republic of China (http: //datacenter.mep.gov.cn/index). Thermo Fisher 1405F monitoring devices were used to measure the PM 2.5 concentrations, and this instrument operates on the principle of measuring PM 2.5 concentrations by a filter dynamic measurement system (FDMS) with the tapered element oscillating microbalance (TEOM) and the beta-attenuation method [6]. Thermo Fisher 1405F monitoring devices were used to measure the PM2.5 concentrations, and this instrument operates on the principle of measuring PM2.5 concentrations by a filter dynamic measurement system (FDMS) with the tapered element oscillating microbalance (TEOM) and the beta-attenuation method [6].…”

“…Their structure is shown in Figure 2b. Thermo Fisher 1405F monitoring devices were used to measure the PM2.5 concentrations, and this instrument operates on the principle of measuring PM2.5 concentrations by a filter dynamic measurement system (FDMS) with the tapered element oscillating microbalance (TEOM) and the beta-attenuation method [6].…”

“…These trajectories mainly pass over waters and coastal areas in eastern Shandong. These areas are characterized by strong air masses, cleanliness, and intensive atmospheric wet deposition, which facilitate wet deposition and dilution of pollutants [1,6,42].…”

“…With rapid socioeconomic development, accelerated industrialization, and continuously increasing energy consumption, particulates have become major urban air pollutants in China [1][2][3]. In particular, fine particulates PM 2.5 can not only reduce atmospheric visibility but also increase mortality and incidence of diseases such as respiratory diseases [4][5][6], and these particulates have aroused great public concern and attention. Studies have indicated that urban air pollution levels and their spatiotemporal distributions are not only associated with local emissions but also influenced by cross-regional transport from sources in surrounding areas [7][8][9].…”

“…(4) More attention should be paid to short-distance transport from the surrounding areas of Weifang, and a joint pollution prevention and control mechanism is critical for controlling regional pollution. Li et al (2018Li et al ( , 2019 indicated that PM 2.5 concentration and its influencing factors varied in different seasons, and they also preliminarily showed that the air pollution in Weifang City was affected by meteorological conditions and pollution of surrounding cities [6,15]. The above-mentioned studies are based on qualitative analysis.…”