Studies have shown that pollution disproportionately affects communities where economically disadvantaged people and Hispanic, Black and Asian people live. Scientists have begun documenting these disparities in detail, but information on daily variations has been lacking. Today, scientists report preliminary work calculating how inequities in exposure fluctuate daily across 11 major U.S. cities. And in some places, climate change could exacerbate these differences.Studies have shown that pollution disproportionately affects communities where economically disadvantaged people and Hispanic, Black and Asian people live. Scientists have begun documenting these disparities in detail, but information on daily variations has been lacking. Today, scientists report preliminary work calculating how inequities in exposure fluctuate daily across 11 major U.S. cities. And in some places, climate change could exacerbate these differences.