title: Spatial and Temporal Variations of PM2.5 and Its Relation to Meteorological Factors in the Urban Area of Nanjing, China.
abstract: The serious air pollution problem has aroused widespread public concerns in China. Nanjing city, as one of the famous cities of China, is faced with the same situation. This research aims to investigate spatial and temporal distribution characteristics of fine particulate matter (PM2.5) and the influence of weather factors on PM2.5 in Nanjing using Spearman-Rank analysis and the Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) method. Hourly PM2.5 observation data and daily meteorological data were collected from 1 April 2013 to 31 December 2015. The spatial distribution result shows that the Maigaoqiao site suffered the most serious pollution. Daily PM2.5 concentrations in Nanjing varied from 7.3 μg/m³ to 336.4 μg/m³. The highest concentration was found in winter and the lowest in summer. The diurnal variation of PM2.5 increased greatly from 6 to 10 a.m. and after 6 p.m., while the concentration exhibited few variations in summer. In addition, the concentration was slightly higher on weekends compared to weekdays. PM2.5 was found to exhibit a reversed relation with wind speed, relative humidity, and precipitation. Although temperature had a positive association with PM2.5 in most months, a negative correlation was observed during the whole period. Additionally, a high concentration was mainly brought with the wind with a southwest direction and several relevant factors are discussed to explain the difference of the impacts of diverse wind directions.
authors.affiliation: Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China. chrisplum@smail.nju.edu.cn.
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.affiliation: Nanjing Information Center, Nanjing 210019, China. hejun@njnet.gov.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: He
authors.affiliation: School of the Environment, Nanjing University, Nanjing 210023, China. glxiaowei123@163.com.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Lu
authors.affiliation: Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China. gisjf@nju.edu.cn.
authors.forename: Jiangfeng
authors.initials: J
authors.lastname: She
authors.affiliation: Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China. zhongqingguan@gmail.com.
authors.forename: Zhongqing
authors.initials: Z
authors.lastname: Guan
mesh_terms: D000393:Air Pollutants / Q000737:chemistry*; D000397:Air Pollution / Q000032:analysis; D002681:China; D002947:Cities; D004784:Environmental Monitoring / Q000379:methods*; D052638:Particulate Matter / Q000737:chemistry*; D012621:Seasons; D013696:Temperature; D014887:Weather; D014919:Wind
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter
keywords: CEEMDAN; Nanjing; PM2.5; meteorological factors; spatial and temporal variations