  While human mobility plays a crucial role in determining air pollution
exposures and health risks, research to-date has assessed risks based solely on
residential location. Here we leveraged a database of ~ 130 million workers in
the US and published PM2.5 data between 2011-2018 to explore how incorporating
information on both workplace and residential location changes our
understanding of disparities in air pollution exposure. In general, we observed
higher workplace exposures (W) relative to home exposures (H), as well as
increasing exposures for non-white and less educated workers relative to the
national average. Workplace exposure disparities were higher among racial and
ethnic groups and job-types than by income, education, age, and sex. Not
considering workplace exposures can lead to systematic underestimations in
disparities to exposure among these subpopulations. We also quantified the
error in assigning workers H, instead of a weighted home-and-work (HW)
exposure. We observed that biases in associations between PM2.5 and health
impacts by using H instead of HW were highest among urban, younger populations.
