A homogenized daily in situ PM 2.5 concentration dataset from the national air quality monitoring network in China

[摘要] In situ PM 2.5 concentration observations have long been used as critical data sources in haze-related studies. Due to the frequently occurring haze pollution events, China started to regularly monitor PM 2.5 concentration nationwide from the newly established air quality monitoring network in 2013. Nevertheless, the acquisition of these invaluable air quality samples is challenging given the absence of a publicly available data download interface. In this study, we provided a homogenized in situ PM 2.5 concentration dataset that was created on the basis of hourly PM 2.5 data retrieved from the China National Environmental Monitoring Center (CNEMC) via a web crawler between 2015 and 2019. Methods involving missing value imputation, change point detection, and bias adjustment were applied sequentially to deal with data gaps and inhomogeneities in raw PM 2.5 observations. After excluding records with limited samples, a homogenized PM 2.5 concentration dataset comprising of 1309 5-year long PM 2.5 data series at a daily resolution was eventually compiled. This is the first attempt to homogenize in situ PM 2.5 observations in China. The trend estimations derived from the homogenized dataset indicate a spatially homogeneous decreasing tendency of PM 2.5 across China at a mean rate of about − 7.6 % per year from 2015 to 2019. In contrast to raw PM 2.5 observations, the homogenized data record not only has complete data integrity but is more consistent over space and time. This homogenized daily in situ PM 2.5 concentration dataset is publicly accessible at https://doi.org/10.1594/PANGAEA.917557 (Bai et al., 2020a) and can be applied as a promising dataset for PM 2.5 -related studies such as satellite-based PM 2.5 mapping, human exposure risk assessment, and air quality management.

[学科分类] 眼科学