On the linkage between urban heat island and urban pollution island: Three-decade literature review towards a conceptual framework

Abstract

With the doubling of urban population within the next two decades and the disproportionate growth of megacities, it is critical to explore the synergism between urban heat and pollution. In this paper, a systematic review is conducted on the existing knowledge, collected since 1990, on the link between urban heat island (UHI) and urban pollution island (UPI). Results from 16 countries and 11 Köppen-Geiger climatic zones are perused and compared to delineate methodological and experimental trends, geographical dependencies and research gaps. Detailed content analysis is conducted according to five prominent topics: i) the role of UHI on temperature-dependent chemistry, ii) the daytime/nighttime variability in the UHI-UPI interaction, iii) the role of urban geomorphic types, forms and growth schemes, iv) future trends and v) primary and secondary effects of UHI mitigation on urban air quality. Different approaches and observations are eventually harmonized to outline opportunities and challenges towards the disentanglement and/or the two-way mitigation of both phenomena. This will help governments and urban planners to deliver coping strategies and precautions towards a more salutogenic urban design.

Exploring coupling effect between urban heat island effect and PM2.5 concentrations from the perspective of spatial environment

“…Researchers in different fields are trying to find a solution to the urban heat island intensity (UHII) and air pollutant concentrations [7][8][9][10]. Part of the results indicate that there is a close coupling effect between the UHII and urban air pollutant concentrations, which has been confirmed by relevant research [11][12][13]. For instance, Estournel et al [14] found out that the temperature of urban and rural areas in Toulouse varies with the aerosol based on the results of solar radiation.…”

Concentrations of Four Major Air Pollutants among Ecological Functional Zones in Shenyang, Northeast China

“…Therefore, we excluded this station from analyses of the relationships between land-use type and air pollutant concentration. At local scale, anthropogenic activities and their urban distribution play an important role for urban pollution [26]. Junk et al [50] indicated that land use and its interaction with other factors can influence air quality.…”

“…Additionally, temperature [22], relative humidity [23], wind direction [24], temperature inversion [25], and so on are related to dispersion and transformation of air pollutants. On the other hand, the intricate feedback loop between urban heat island, temperature-driven chemistry and urban pollution, urbanization also plays an important role for the air quality [26]. Land cover [27], high population density [28], and heavy traffic [29] all can affect pollutants' concentrations.…”

Empirical evidence on the impact of urban overheating on building cooling and heating energy consumption

“…While the repercussions of urban overheating are multifaceted and naturally diverse, they can be subtly grouped into three broad categories: (I) direct impact on urban dwellers in terms of exerted thermal stress, especially in the summertime or periods of extreme heat events and which results in increased heat-related thermal discomfort, mortalities, and morbidities ( Founda and Santamouris, 2017 ; He et al., 2021 ; Ngarambe et al., 2020 ), (II) heightened urban air pollution levels resulting from synergistic interactions between UHI-related elevated temperatures and atmospheric pollutants often fueled by complex photochemical processes ( Cao et al., 2016 ; Ngarambe et al., 2021 ; Ulpiani, 2021 ), and (III) a serious impact on the energy demand of cities; they increase the cooling load and partially decrease the heating load ( Li et al., 2019 ; Santamouris, 2014 ).…”