Examining the causal effects of air pollution on dockless bike-sharing usage using instrumental variables

Dockless bike-sharing (DBS) has proliferated worldwide. Despite DBS’s great potential to reduce air pollution, air pollution may also reduce the usage of DBS. However, not much research attention has been paid to the effects of air pollution on DBS usage. Existing attempts have mostly relied on traditional data sources and intended to establish associations, not causalities. To address this research gap, we compile a panel data set with more than 50 million DBS trip records and high-frequency air quality and weather monitoring readings over a 92-day period in Chengdu, China. We then estimate the causal effects of air pollution on DBS usage using an instrumental variable approach. We find that a 10 μg/m3 increase in PM2.5 concentrations leads to a 2.5% reduction in DBS usage. Furthermore, such adverse effects are particularly pronounced among young DBS users, during non-peak hours, for long-distance trips, and in census tracts with low housing prices.