While the high activity of LDVs causes a higher aggregate impact on disparity, HDVs stand out as the fleet type whose emissions cause the most disparate impact on Californians of color. As a complement to apportioning the overall absolute exposure disparity to emissions from individual vehicle types (i.e., largest aggregate impact), in Fig. we also consider which vehicle fleet types have an especially disparate impact on specific racial-ethnic groups (largest relative impact regardless of magnitude of emissions) relative to the statewide population. For example, the relative disparity caused by HDVs for Hispanic Californians (range: 16 -17%) was larger than the relative disparity caused by LDVs (range: 11 -14%). This difference in impacts by fleet type is consistent with recent traffic equity modeling, which demonstrated that the majority of Californians of all race-ethnicity are exposed to high annual average daily traffic from LDVs, but Californians of color are disproportionately exposed to higher annual average daily traffic from HDVs . Another useful metric for discussing the especially disparate impact of HDVs is the exposure inequality, defined by Demetillo et al. as the percent difference in exposure between the most-and least-exposed racial-ethnic groups. Based on our results the PM2.5 inequality for Hispanic Californians, relative to white Californians, increases from 37% in 2000 to 41% in 2019. This finding complements recent work that shows the importance of HDV emission mitigation for reducing racial-ethnic disparity .