Check out our paper showing that the future of urban air quality requires consideration of non-combustion emissions, a highly diverse mix of sources like consumer/commercial products and materials. It published as a highlight paper in ACP (https://www.atmos-chem-phys.net/18/5391/2018/)(ACPD in August 2017). See more at Yale News: https://seas.yale.edu/news-events/news/study-shows-need-broaden-focus-sources-air-pollution.