Relationship Between Fine-Particle Pollution and the Urban Heat Island in Beijing, China: Observational Evidence

PM2.5 Pollution Modulates Wintertime Urban Heat Island Intensity in the Beijing‐Tianjin‐Hebei Megalopolis, China

“…Accordingly, UHII ave gradually decreased, varying from 2.9 °C on 27 December to 2.82 °C on 28 December and to 2.67 °C on 29 December, corresponding to the CR of UHII ave of −54.3% and −25.1%, respectively, and UHII max (UHII min ) weakened (enhanced) gradually. These results suggest that UHII decreases with increasing PM 2.5 concentration, consistent with the observations of Zheng, Ren, et al ().…”

“…Recently, Zheng, Ren, et al () revealed that the downward shortwave radiation at the surface decreased with the increase in PM 2.5 concentration in Beijing, leading to a weaker daytime UHII, but a stronger nighttime UHII. Until now, there is a gap in the understanding of the impacts of PM 2.5 pollution on UHI with their regional differences in the Beijing‐Tianjin‐Hebei (BTH) region of China (Li et al, ; Ren et al, , ; Zhou et al, ), which is among the areas with the highest population densities and fastest urbanization rates in the world.…”

Effects of urbanization and global climate change on regional climate in the Pearl River Delta and thermal comfort implications

“…At night‐time, the stored heat was released (Roth, ; Feng et al ., ; Wang et al ., ), which may increase the minimum temperature. Nevertheless, the stored heat was also horizontally transported to the U/U areas (typically an urban core) by urban heat island circulations (Liu et al ., ; Zheng et al ., ). The minimum temperature thus did not increase obviously in the N/U areas.…”

Re‐evaluating the variation in trend of haze days in the urban areas of Beijing during a recent 36‐year period

“…In spring (March–May), summer (June–August), autumn (September–November), and winter (December–February), the average numbers of haze days in Beijing are 9.7, 11, 16.5, and 15.9 days, respectively, accounting for 17.8, 19.6, 31.7, and 30.9% of the haze days over an entire year, implying haze occurs more frequently in autumn and winter than in spring and summer. The differences in seasonal haze days can be explained as follows: because Autumn and winter are traditional heating and coal‐burning seasons in northern China, the haze days in autumn and winter are relatively higher because of the concentrated population and the consequent increased energy consumption and unfavorable meteorological conditions (Cai et al, ; Pei et al, ; Yang et al, ; Zheng et al, ). While the lower haze days in spring are closely related to the large average wind speed and more windy days during this period, and those in summer are mainly corresponding to more wet deposition of precipitation (Miao et al, ; Zheng et al, ).…”

“…On the other hand, previous work has shown that the weather conditions determine the pollutant diffusion, depending on the wind speed, wind direction, relative humidity, assuming pollutants are released steadily (Ding and Liu, ; Zhang et al, ). In addition, inter‐annual variability and the long‐term trend of heavy haze pollution are sensitive to the natures of the local and large‐scale circulations (Che et al, ; Ji et al, ; Chen and Wang, ; Miao et al, , , ; Cai et al, ; Zheng et al, ). Therefore, for the establishment of observationally long‐term variations and trends of haze days, it is important that a reference observation station is suitably selected to explore the haze trend and its relationship with climate variability.…”