Spatiotemporal Patterns of Ground Monitored PM2.5 Concentrations in China in Recent Years.

Junming Li,Xuejiao Li,Xiulan Han,Xiao Li,Jianping Yang

doi:10.3390/ijerph15010114

Abstract

This paper firstly explores the space-time evolution of city-level concentrations showed a very significant seasonal cycle type fluctuation during the period between 13 May 2014 and 30 May 2017. The period from October to April following each year was a heavy pollution period, whereas the phase from April to October of the current year was part of a light pollution period. The average monthly concentrations in mainland China based on ground monitoring, employing a descriptive statistics method and a Bayesian spatiotemporal hierarchy model. Daily and weekly average concentrations in 338 cities in mainland China presented no significant spatial difference during the severe pollution period but a large spatial difference during light pollution periods. The severe pollution areas were mainly distributed in the Beijing-Tianjin-Hebei urban agglomeration in the North China Plain during the beginning of each autumn-winter season (September), spreading to the Northeast Plains after October, then later continuing to spread to other cities in mainland China, eventually covering most cities. pollution in China appeared to be a cyclic characteristic of first spreading and then centralizing in the space in two spring-summer seasons, and showed an obvious process of first diffusing then transferring to shrinkage alternation during the spring-summer season of 2015, but showed no obvious diffusion during the spring-summer season of 2016, maintaining a stable spatial structure after the shrinkage in June, as well as being more concentrated. The heavily polluted areas are continuously and steadily concentrated in East China, Central China and Xinjiang Province.

Highlights

Since the beginning of the 21st century, air pollution, especially PM2.5 pollution, has caused more than 2 million deaths each year worldwide [1], leading to an increase in hospitalization and mortality rates for asthma and chronic obstructive pulmonary disease (COPD) [2,3]
PM2.5 pollution in mainland China over the most recent three years based on available ground monitoring station data
The study findings are: (i) PM2.5 pollution in mainland China showed a very significant seasonal cycle type fluctuation, with the period from October to April following a previous year being a heavy pollution period, while the phase from April to October of the current year belonged to the light pollution period

Summary

Introduction

Since the beginning of the 21st century, air pollution, especially PM2.5 pollution, has caused more than 2 million deaths each year worldwide [1], leading to an increase in hospitalization and mortality rates for asthma and chronic obstructive pulmonary disease (COPD) [2,3]. When the PM2.5 concentration in the air is higher than 10 μg/m3 for a significant period of time, the risk of death increases significantly, on the basis of 10 μg/m3 ; with every additional 10 μg/m3 increase, the total risk of death increases by 4%, with the risk of death from lung cancer and heart disease increasing by 8% and 6%, respectively [4]. Chen et al [5] found that prolonged exposure to an environment with an additional 100 μg/m3 increase of total suspended particulate matter would result in an average reduction of about 3 years in life expectancy [5]. Public Health 2018, 15, 114; doi:10.3390/ijerph15010114 www.mdpi.com/journal/ijerph

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Results

Discussion

Conclusion