Impact of Urban Land Use and Anthropogenic Heat on Air Quality in Urban Environments

Abstract

In the GEM-MACH URBAN project, Environment and Climate Change Canada (ECCC) high-resolution (2.5-km) Global Environment Multiscale-Modelling Air-quality and Chemistry (GEM-MACH) model and the Town Energy Balance Model (TEB) are being employed to examine the impact of the urban surface exchange scheme on the transport and diffusion of air pollutants in large cities such as Toronto, New York and Detroit. Simulation results show that while the TEB scheme causes O3 mixing ratios to increase, it leads to a decrease of CO and NOx mixing ratios and air quality health index (AQHI) values in the urban centers in both summer (July) and winter (January) months. The TEB scheme also has a big impact on the vertical diffusion coefficient, atmospheric boundary layer (ABL) height and air temperature. Comparisons against ECCC’s meteorological and air quality (AQ) observation networks suggest that the inclusion of TEB scheme improves the forecasts of both surface temperature and pollutant mixing ratios.