Air quality influenced by urban heat island coupled with synoptic weather patterns.

Few studies have discussed the association between the urban heat island (UHI) phenomenon and air quality under synoptic weather patterns conducive to UHI. In this study, the authors used statistical analyses to study this association in the Taichung metropolis region. The air quality data obtained from government-owned observation stations and wind field profiles obtained from tethersonde monitoring (performed during 21-29 October 2004) were combined with the simulations of the horizontal wind fields at different heights by the air pollution model (TAPM). The results show that certain specific synoptic weather patterns worsen the air quality and induce the UHI phenomenon: Taichung's UHI appears clearly under the synoptic weather patterns featuring light air or breezes (0.56 m/s < or =wind speed <2.2 m/s) mainly from the north and west. Furthermore, under these weather patterns, the concentrations of air pollutants (NO2, CO2 and CO) increase significantly (P<0.05) with the UHI intensity. The convergence usually associated with nocturnal UHI causes the accumulation of O3 precursors, as well as other air pollutants, thereby worsening the air quality at that time and also during the following daytime period.

[1]  K. Baumann,et al.  Analysing the nocturnal wind field in the city of Graz , 2001 .

[2]  H. Yoshikado,et al.  High Levels of Winter Air Pollution under the Influence of the Urban Heat Island along the Shore of Tokyo Bay , 1996 .

[3]  J. Labajo,et al.  The urban heat island in Salamanca (Spain) and its relationship to meteorological parameters , 2007 .

[4]  Qihao Weng,et al.  Urban Air Pollution Patterns, Land Use, and Thermal Landscape: An Examination of the Linkage Using GIS , 2006, Environmental monitoring and assessment.

[5]  Ronald P. Cody,et al.  Applied Statistics and the SAS Programming Language , 1986 .

[6]  William R. Cotton,et al.  Interactions of an urban heat island and sea-breeze circulations during winter over the metropolitan area of São Paulo, Brazil , 2007 .

[7]  Dehua Zhao,et al.  A fieldwork study on the diurnal changes of urban microclimate in four types of ground cover and urban heat island of Nanjing, China , 2008 .

[8]  Valéry Masson,et al.  Simulation of a Summer Urban Breeze Over Paris , 2002 .

[9]  Liangjun Da,et al.  Ecological consequences of rapid urban expansion: Shanghai, China , 2006 .

[10]  Wan-Li Cheng.  Synoptic weather patterns and their relationship to high ozone concentrations in the Taichung Basin , 2001 .

[11]  P. Manins,et al.  Year-long, high-resolution, urban airshed modelling: verification of TAPM predictions of smog and particles in Melbourne, Australia , 2003 .

[12]  Min-Der Lin,et al.  Wintertime vertical profiles of air pollutants over a suburban area in central Taiwan , 2002 .

[13]  C. Rosenzweig,et al.  Urban Heat Island and Climate Change : An Assessment of Interacting and Possible Adaptations in the Camden , New Jersey Region , 2004 .

[14]  B. Tsuang,et al.  Synoptic patterns in relation to ozone concentrations in west-central Taiwan , 2001 .

[15]  I. Eliasson,et al.  Suspended particulate matter and its relations to the urban climate in Dar es Salaam, Tanzania , 2004 .

[16]  K. Steffen,et al.  Ozone and meteorological boundary-layer conditions at Summit, Greenland, during 3–21 June 2000 , 2002 .

[17]  C. Wu,et al.  Study on an ozone episode in hot season in Hong Kong and transboundary air pollution over Pearl River Delta region of China , 2005 .

[18]  M. Roth,et al.  Temporal dynamics of the urban heat island of Singapore , 2006 .

[19]  Jong‐Jin Baik,et al.  Daily maximum urban heat island intensity in large cities of Korea , 2004 .

[20]  C. Sarrata,et al.  Impact of urban heat island on regional atmospheric pollution , 2006 .

[21]  A. Chandrasekar,et al.  Numerical study of the effects of urban heat island on the characteristic features of the sea breeze circulation , 1998, Journal of Earth System Science.