Evaluating the effects of compact growth on air quality in already-high-density cities with an integrated land use-transport-emission model: A case study of Xiamen, China

Urban form may play an important role in improving air quality, but studies on already-high-density cities are relatively limited. In this paper, we developed an integrated land use-transport-emission model with TRANUS and MOBILE 6.2, selected an already-high-density city, Xiamen, as the study area, and explored the effects of compact growth on traffic emissions and exposure to air pollution. The results show that compact growth may significantly reduce regional traffic emissions even in an already-high-density city, but high-density developments may result in higher population-weighed exposures to air pollution. The finding implies that compact growth strategies should be carried out and the metric of population-weighed exposures should be considered in already-high-density cities. Integrated land use-transport-emission models may serve as a useful tool for urban planning agencies to decide appropriate locations for urban growths.