Satellite and Ground Observations of Severe Air Pollution Episodes in the Winter of 2013 in Beijing, China

Shenshen Li,David C Christiani,Xiaozhen Xiong,Yang Liu,Zhaoxi Wang,Zongwei Ma

doi:10.4209/aaqr.2015.01.0057

Abstract

ABSTRACTBeginning in early January 2013, Beijing experienced multiple prolonged and severe smog events that were characterized by very high levels of PM2.5, with peak daily PM2.5 over 400 µg m–3. With PM2.5 concentration contours created from ground observations and satellite remote sensing data, we describe the spatial and temporal characteristics of these episodes and further investigated the factors that contributed to these episodes. Our results indicated that these smog episodes affected a much larger geographic region, far beyond Beijing metropolitan area, corresponding to a total area of ~550,000 km2 and ~180 million people. The extremely cold weather in December 2012 and regional pollution transport were likely the main causes of these severe PM pollutions. In addition to aggressive emission control measures for Beijing, coordinated regional policy must be put in place to achieve more blue-sky days. Although the configuration of the current ground monitoring network may be sufficient to record PM2.5 levels in urban centers, these monitors alone cannot fully characterize the spatial pattern and track the transport of air pollution on a regional scale. Satellite remote sensing data can provide valuable information to fill the gaps left by ground monitors to create a more comprehensive picture of PM2.5.

Highlights

Smog, or the mixture of smoke and fog, is a severe air pollution event often characterized by hazy air and reduced visibility
With PM2.5 concentration contours created from ground observations and satellite remote sensing data, we describe the spatial and temporal characteristics of these episodes and further investigated the factors that contributed to these episodes
The highest PM2.5 concentration occurred on January 12th, 2013

Summary

Introduction

The mixture of smoke and fog, is a severe air pollution event often characterized by hazy air and reduced visibility. Smog episodes can be caused by various natural and anthropogenic factors, such as forest fires, agricultural burning, fossil fuel combustion, and industrial emissions; and are exacerbated by unfavorable meteorological conditions It is a serious problem in many large cities in the world and continues to harm human health (Chen et al, 2007). There were several well-known lethal smog episodes, including the air pollution events, in the heavily industrialized Meuse Valley (Belgium) in December 1930, in Donora (the United States) in October 1948, and in London (the United Kingdom) in December 1952. The spatial distribution of these PM2.5 monitoring stations is heavily biased towards major cities in China, with very limited coverage elsewhere

Results

Discussion

Conclusion