Research Article Spatiotemporal Patterns and Cause Analysis of PM 2.5 Concentrations in Beijing, China Guangjin Tian , 1 Xiaojuan Liu, 2 and Lingqiang Kong 2 1 School of Government, Beijing Normal University, Xinjie Kouwai Street, Beijing 100875, China 2 State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Xinjie Kouwai Street, Beijing 100875, China Correspondence should be addressed to Guangjin Tian; tianguangjin@bnu.edu.cn Received 5 October 2017; Revised 28 November 2017; Accepted 30 November 2017; Published 15 February 2018 Academic Editor: Julio Diaz Copyright © 2018 Guangjin Tian et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. According to the monthly comprehensive air index ranking in China in 2016, Beijing ranked in the bottom tenth three times, indicating that the air pollution situation is very serious compared to other cities in China. In this study, we chose 23 urban environmental assessment points, which covered all districts and counties in Beijing. We used ArcGIS sofware to analyze atmospheric concentrations of particulate matter with a diameter < 2.5 m (PM 2.5 ) for each month of 2016 in each district/county of Beijing. Our results showed that PM 2.5 concentrations in winter and spring were generally higher than those in summer and autumn. Te higher monthly average PM 2.5 concentrations were primarily in the southwest and southeast areas. Te higher annual average values were distributed in Fangshan, Daxing, and Tongzhou, which were closely related to the high terrain in the northwest and the low-lying terrain in the southeast, the “Beijing Bay” terrain, and local climatic conditions. Te temporal and spatial distributions of PM 2.5 constitute a warning signal for human life and production during diferent seasons and regions. 1. Introduction In recent years, the frequent occurrence of haze events has gradually infuenced human health and living. Te composition of haze is very complex, including hundreds of atmospheric particles [1]. Aerosol particles 10 m in diameter are the most harmful particles for human health: foating dust, aerosols, and inhalable particles can directly enter the human body and adhere to the upper and lower respiratory tract and lungs, causing rhinitis, bronchitis, and other diseases. Tese particles will induce lung cancer if they exist in this environment for a long time. Particles > 10 m do not easily enter the respiratory tract. Most 5–10 m particles are deposited in the upper respiratory tract, whereas most 2.5–5 m particles are deposited in the bronchioles and alveoli. However, about 75% of particles < 2.5 m (PM 2.5 ) in diameter are deposited in alveoli. Because the alveolar area has a large surface area and the alveolar wall has an abundant capillary network, the soluble fraction (including some heavy metals) is easily absorbed into the blood and has efects in the human body, while the insoluble fraction, as a foreign body, is phagocytized by macrophages, causing an infammatory reaction. In addition, PM 2.5 also damage the cardiovascular and nervous systems. Although PM 2.5 particles are small, a large number of toxic and harmful substances readily attach to them. Particles attached to toxic substances have the characteristics of long duration and long- distance transportation in the atmosphere, causing a greater impact on human health and the atmosphere. In February 2012, the State Council of China revised and issued an Ambient Air Quality Standard (GB3095-2012), in which PM 2.5 was added as a new monitoring indicator. PM 2.5 is equivalent to 1/20 the diameter of a human hair, and particles of this size directly enter the lungs. Although PM 2.5 content is very small compared to other components of the Earth’s atmosphere, they have important implications for air quality and visibility. In 2013, PM 2.5 was identifed as a primary carcinogen by the International Cancer Research Institute. Te composition of PM 2.5 is very complex and mainly depends on the source, which can be natural (soil dust, volcanic eruption, and forest fres) or anthropogenic (burning of fossil fuels, emission of motor vehicles, and Hindawi Advances in Meteorology Volume 2018, Article ID 1724872, 8 pages https://doi.org/10.1155/2018/1724872