PM_2.5 Pollution Modulates Wintertime Urban Heat Island Intensity in the Beijing‐Tianjin‐Hebei Megalopolis, China

Abstract

Heavy PM2.5 (particulate matter with aerodynamic diameter equal to or less than 2.5 μm) pollution and urban heat island (UHI) pose increasing threats to human health and living environment in populated cities. However, how PM2.5 pollution affects the UHI intensity (UHII) has not been fully understood. The impacts of PM2.5 on the wintertime UHII in the Beijing‐Tianjin‐Hebei megalopolis of China are explored during 2013–2017. The results show that the UHII at the time of daily maximum/minimum temperature (UHIImax/UHIImin) exhibits a decreasing/increasing tendency as PM2.5 concentration increases, causing a continuous decrease in the diurnal temperature range. These effects are mediated via aerosol‐radiation interaction (aerosol‐cloud interaction) under clear‐sky (cloudy) condition. The changes in PM2.5 concentration further cause different relative trends of UHIImax/UHIImin/diurnal temperature range across different cities in the Beijing‐Tianjin‐Hebei region, which are likely related to the differences in both the PM2.5 composition and city size. This study provides insights on how air pollution affects urban climate and would help to design effective mitigation strategies.

The mechanisms and seasonal differences of the impact of aerosols on daytime surface urban heat island effect

“…A generalized split-window algorithm is applied using MODIS data from two longwave bands in the atmospheric window to correct for atmospheric water vapor, haze effects, and the sensitivity to errors in the surface emissivity. Changes in surface emissivity have been taken into account to obtain the LST from brightness temperatures (Wan and Dozier, 1996;Snyder et al, 1998;Wang and Liang, 2009;Yu et al, 2011;Cao et al, 2016).…”

Daily Global Solar Radiation in China Estimated From High‐Density Meteorological Observations: A Random Forest Model Framework

“…In recent years, there has been an aggravation of air pollution in China induced by massive fossil fuel consumption and emissions coinciding with unfavorable weather conditions (Guo et al, , ; Lou et al, ; Yang, et al, ; Yang, Ye, et al, ; Zheng et al, ). On the one hand, this has significantly modulated the change in surface solar radiation (Che et al, ; Guo et al, ; Wang et al, , ; Wang & Wild, ; Zheng et al, ; He & Wang, ; Yang et al, ), while on the other hand, it has led to solar radiation becoming one of the fastest‐growing and important sources of clean and renewable energy. Therefore, solar radiation is a topic that has attracted broad and increasing attention in China (Che et al, ; Sun et al, ; Li et al, ; Wang et al, ; Song et al, ; Tang et al, , ; Liu et al, ; He & Wang et al, ).…”

“…However, to date, field observations have been insufficient and solar radiation monitoring stations are distributed unevenly and sparsely across the globe, meaning high‐spatial‐resolution and high‐density DGSR information still remains limited. Besides, high uncertainty also exists in the estimation of solar radiation received at the Earth's surface, mainly due to the influences of astronomical, meteorological, and regional factors (Che et al, ; Sun et al, ; Wang et al, , ; Wang & Wild, ; Liu et al, ; He & Wang, ; Yang et al, ). Therefore, a reliable and high‐density DGSR observational network and information on the spatiotemporal distribution of surface solar radiation are an ongoing core issue in energy studies (Jiang, ; Wang et al, ; Zhang et al, ; Assouline et al, ; Halabi et al, , Qin et al, ).…”

The interaction between urbanization and aerosols during a typical winter haze event in Beijing

“…Urbanization, as the most drastic means by which human activities transform the environment, has had an important impact on regional climate and weather processes (Miao et al, 2011;Yu and Liu, 2015;Yu et al, 2017). Existing research suggests that there are three main ways by which urbanization influences the climate (Oke, 1982(Oke, , 1995.…”