Urban vibrancy and air pollution: avoidance behaviour and the built environment

Urban vibrancy can be captured by people's out-of-home mobility. It is an essential indicator of the 'liveliness' of cities. Nowadays, many cities, however, are suffering from air pollution, which is harmful to human health. As such, health authorities are advising people, especially vulnerable groups with respiratory or other chronic diseases, to avoid out-of-home activities and travels on polluted days. With such avoidance behaviour, how would urban vibrancy decline in response to air pollution? How does the built environment moderate such declines? Applying spatial econometric approaches on panel data comprising social media check-in records, air quality index, meteorological conditions and built environment characteristics, this paper delves into the relationship between air pollution and urban vibrancy in Guangzhou using fine spatial (1km*1 km grids) and temporal (daily) data over two years from 2018 to 2019. The research findings provide clear evidence that air pollution is negatively associated with urban vibrancy. Furthermore, our study suggests that urban vibrancy of places with higher points of interest intensity and being farther away from the city centre are more affected by air pollution, whereas vibrancy of places with higher public transport convenience, smaller blocks, and higher functional mixture tend to be less vulnerable. The findings provide evidence-based implications for city governments to better understand and capture gains of urban vibrancy from pollution regulations and built environment design for sustainable urban development. The lessons learned are applicable to other cities with emerging air pollution problems.