Combining Remote Sensing and Cell Phone Users' Mobility Data to Monitor the Impact of Transportation on NO2 Concentrations in India

Estimating the extent to which transportation contributes to air pollution levels has been hampered by the difficulty in separating the relative degree of ambient nitrogen dioxide generated by transportation, power generation, and industrial activity'all of which play roles. This paper addresses this gap by isolating the impact of ground-level mobility on air pollution in India through a combination of remotely sensed tropospheric nitrogen dioxide measures and data from mobile phone users' locations. The paper constructs vectors of ground-level movement of cell phones to estimate the impact of daily changes in mobility within a given district, controlling for both daily thermal electricity generation from upwind power plants and trends in ambient pollution concentrations over time and space. The findings show that tropospheric nitrogen dioxide concentrations are very responsive to changes in mobility, and that the effect varies with population density. The findings show that a 1 percent increase in mobility increases nitrogen dioxide concentrations by more than 2 percent, suggesting that traffic congestion plays a significant role in air pollution