These findings further underscore the importance of addressing both exhaust and non-exhaust emissions when formulating policies to mitigate vehicle-related air pollution, particularly for HDVs and MDVs, which contribute significantly to overall exposure. Note. LDV = light-duty vehicle; MDV = medium-duty vehicle; HDV = heavy-duty vehicle. Average PM2.5 exposure represents the sum of PM2.5 exposure from exhaust, brake wear particulate, and tire ware particulate.