The University of California, Los Angeles’ Fielding School of Public Health conducted the study. It determined that fast chargers’ emissions are most likely related to their cooling fans, which can kick up particles like brake dust and tire fragments into the air. Researchers looked at 50 DC fast chargers, most of which were Tesla Superchargers, finding that the air around them was slightly dirtier than the air at gas stations and much dirtier than neighborhoods and parks nearby.