Keywords
Urban Heat Island; Nitrogen Dioxide; Urban Population; Scaling; Meta-Analysis
Start Date
16-9-2020 11:20 AM
End Date
16-9-2020 11:40 AM
Abstract
Due to urban population growth worldwide, thermal anomalies and toxic air pollution are increasing concern for citizens. Despite this increasing challenge and indications that these environmental problems increase with city size, there is still no consolidated understanding of the effect of city size on urban heat island (UHI) and nitrogen dioxide (NO2) pollution. Meanwhile, research on urban scaling laws, which formally relates population size and urban characteristics, has been quickly increasing over the past decade but is mostly devoted to the socio-economic outcome of cities rather than pollution or heat stress. Most studies dedicated to UHI or NO2 consider only a single city or analyze a few cities within the top ranks of specific world regions or globally. We intend to fill this gap by conducting a qualitative synthesis of the literature and performing a statistical meta-analysis from published work with the aim to uncover scaling laws of UHI and NO2 with the population size of cities. Under the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline, we collect and filter about 500 research outcomes on UHI and NO2 from Scopus and Google Scholar. We find that moving from a city with a population of 100-thousand to a city with a population of 1 million, the max UHI intensity increases by 2.66 °C, the annual mean NO2 surface concentration increases by 14.95 ����g/m3. Moving from a city having a population of 1 million to a city with a population of 10-million, the max UHI intensity increases by 3.87 °C, the annual mean NO2 surface concentration increases by 21.72 ����g/m3. Thus, larger cities have higher levels of UHI effects and NO2 pollution. We also give the progress of verifying the NO2 scaling using census data and in-situ and RS-measured NO2 data at the level of Urban Atlas 2012.
Scaling of Urban Heat Island and NO2 with Urban Population: A Meta-Analysis
Due to urban population growth worldwide, thermal anomalies and toxic air pollution are increasing concern for citizens. Despite this increasing challenge and indications that these environmental problems increase with city size, there is still no consolidated understanding of the effect of city size on urban heat island (UHI) and nitrogen dioxide (NO2) pollution. Meanwhile, research on urban scaling laws, which formally relates population size and urban characteristics, has been quickly increasing over the past decade but is mostly devoted to the socio-economic outcome of cities rather than pollution or heat stress. Most studies dedicated to UHI or NO2 consider only a single city or analyze a few cities within the top ranks of specific world regions or globally. We intend to fill this gap by conducting a qualitative synthesis of the literature and performing a statistical meta-analysis from published work with the aim to uncover scaling laws of UHI and NO2 with the population size of cities. Under the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline, we collect and filter about 500 research outcomes on UHI and NO2 from Scopus and Google Scholar. We find that moving from a city with a population of 100-thousand to a city with a population of 1 million, the max UHI intensity increases by 2.66 °C, the annual mean NO2 surface concentration increases by 14.95 ����g/m3. Moving from a city having a population of 1 million to a city with a population of 10-million, the max UHI intensity increases by 3.87 °C, the annual mean NO2 surface concentration increases by 21.72 ����g/m3. Thus, larger cities have higher levels of UHI effects and NO2 pollution. We also give the progress of verifying the NO2 scaling using census data and in-situ and RS-measured NO2 data at the level of Urban Atlas 2012.
Stream and Session
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