Understanding sources of fine particulate matter in China

Abstract

Fine particulate matter has been a major concern in China as it is closely linked to issues such as haze, health and climate impacts. Since China released its new national air quality standard for fine particulate matter (PM 2.5 ) in 2012, great efforts have been put into reducing its concentration and meeting the standard. Significant improvement has been seen in recent years, especially in Beijing, the capital city of China. This paper reviews how China understands its sources of fine particulate matter, the major contributor to haze, and the most recent findings by researchers. It covers the characteristics of PM 2.5 in China, the major methods to understand its sources such as emission inventory and measurement networks, the major research programmes in air quality research, and the major measures that lead to successful control of fine particulate matter pollution. A great example of linking scientific findings to policy is the control of coal combustion from the residential sector in northern China. This review not only provides an overview of the fine particulate matter pollution problem in China, but also its experience of air quality management, which may benefit other countries facing similar issues. This article is part of a discussion meeting issue ‘Air quality, past present and future’.

A chronology of global air quality

“…The large increases in emissions of all primary pollutants in South and East Asia have been widely reported and described by Zheng et al [106]. Air quality in Asian megacities shows values for PM, SO 2 and NO 2 in episode conditions that are similar to the highly polluted atmosphere of London in the smog episodes of the 1950s, for example the Beijing ‘haze’ events in January 2012.…”

Abating ammonia is more cost-effective than nitrogen oxides for mitigating PM 2.5 air pollution

“…Air pollution from PM 2.5 (fine particulate matter with a mass median aerodynamic diameter <2.5 μm) has been estimated to cause millions of premature deaths annually in recent years ( 1 , 2 ). Therefore, mitigating PM 2.5 pollution is a high priority for environmental protection in many countries such as China ( 3 ), India ( 4 ), the United States ( 5 ), and the member states of the European Union (EU) ( 6 ). The most cost-effective abatement measures need to be identified to balance environmental protection and economic development.…”

Monitoring of PM2.5 Concentrations by Learning from Multi-Weather Sensors

“…When the number of iterations reached 900, the performance of the algorithm approached saturation. Finally, the multivariate nonlinear regression model was completely fitted after 1081 iterations as PM 2.5 =68.7672e (−0.0001×Visibility) + 8.3784e (0.0029×Wind direction) − 0.0536e (0.7548×Wind speed) + 7.3861e (−0.256×RH) (18) In the training of neural network models, validation is not required due to the use of the Bayesian regularization method. Therefore, the PM data and meteorological parameters were randomly divided into two sets as: 60% for training, and 40% for a completely independent test.…”

“…The mission's payload is the tropospheric monitor, which measures key atmospheric constituents, including ozone, nitrogen dioxide, sulphur dioxide, carbon monoxide, methane, nitrous oxide, and Ultraviolet aerosol index [16]. At the same time, ground based direct samplers were developed to accurately measure PM concentrations [17,18]. Zhang et al [19] demonstrated how vertical wind shear affects ground-level PM 2.5 by using radar wind profiler observations in Beijing, providing new insights into the role of vertical wind shear in modulating the variation of PM 2.5 , which is worth considering in future air quality predictions.…”