A Two-Stage Method to Estimate the Contribution of Road Traffic to PM2.5 Concentrations in Beijing, China

International Journal of Environmental Research and Public Health

Xin Fang³  Runkui Li¹  Qun Xu⁴  Matteo Bottai³  Fang Fang²  Yang Cao³  P. Grady Dixon⁵ 

[1] College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, ChinaDepartment of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm 17177, Sweden;Unit of Biostatistics, Institute of Environmental Medicine, Karolinska Institutet, Stockholm 17177, Sweden;Department of Epidemiology and Biostatistics, Institute of Basic Medicine Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing 100005, China;;Unit of Biostatistics, Institute of Environmental Medicine, Karolinska Institutet, Stockholm 17177, Sweden

关键词: PM_2.5 concentration;    road traffic contribution;    atmospheric dispersion model;    generalized additive mixed model;   

DOI  :  10.3390/ijerph13010124

来源: mdpi

【 摘 要 】

Background: Fine particulate matters with aerodynamic diameters smaller than 2.5 micrometers (PM_2.5) have been a critical environmental problem in China due to the rapid road vehicle growth in recent years. To date, most methods available to estimate traffic contributions to ambient PM_2.5 concentration are often hampered by the need for collecting data on traffic volume, vehicle type and emission profile. Objective: To develop a simplified and indirect method to estimate the contribution of traffic to PM_2.5 concentration in Beijing, China. Methods: Hourly PM_2.5 concentration data, daily meteorological data and geographic information were collected at 35 air quality monitoring (AQM) stations in Beijing between 2013 and 2014. Based on the PM_2.5 concentrations of different AQM station types, a two-stage method comprising a dispersion model and generalized additive mixed model (GAMM) was developed to estimate separately the traffic and non-traffic contributions to daily PM_2.5 concentration. The geographical trend of PM_2.5 concentrations was investigated using generalized linear mixed model. The temporal trend of PM_2.5 and non-linear relationship between PM_2.5 and meteorological conditions were assessed using GAMM. Results: The medians of daily PM_2.5 concentrations during 2013–2014 at 35 AQM stations in Beijing ranged from 40 to 92 μg/m³. There was a significant increasing trend of PM_2.5 concentration from north to south. The contributions of road traffic to daily PM_2.5 concentrations ranged from 17.2% to 37.3% with an average 30%. The greatest contribution was found at AQM stations near busy roads. On average, the contribution of road traffic at urban stations was 14% higher than that at rural stations. Conclusions: Traffic emissions account for a substantial share of daily total PM_2.5 concentrations in Beijing. Our two-stage method is a useful and convenient tool in ecological and epidemiological studies to estimate the traffic contribution to PM_2.5 concentrations when there is limited information on vehicle number and types and emission profile.

【 授权许可】

CC BY   
© 2016 by the authors; licensee MDPI, Basel, Switzerland.