Insights into measurements of ambient air PM2.5 in China

Particulate matter with an aerodynamic diameter of 2.5 mu m or less (PM2.5) is the main air pollutant in many countries. PM2.5 levels vary substantially over time and short distances, which directly affects the interpretation of data collected from reference stations. Although such data are usually accurate for one location at a certain time, they cannot be extrapolated to carry out complete spatial and temporal PM2.5 assessment. China's varying geographies, climates and environment make it challenging to accurately measure ambient air PM2.5 levels. This paper describes the current state of PM2.5 pollution and standard/specifications of monitoring in China, reviews all available PM measurement techniques, highlights the advantages and limitations of the most widely used instruments, and discusses the related challenges. Based on our analysis of PM2.5 measurements, we suggest some ways to improve this measurement in China. In particular, suitable instruments need to be developed to accommodate different environments, climates and pollution levels across China. However, it is important to note that monitoring is merely a way to measure pollution levels, and not the main purpose of our research. The final purpose we have is creating a healthy and comfortable living environment for China's residents. (C) 2017 Elsevier B.V. All rights reserved.