Epidemiological studies have established a strong correlation between inhaling ultrafine particles from incomplete combustion and respiratory and cardiovascular diseases. Still, relatively little is known about the mechanisms behind how air particulates affect human health. New work seeks to provide the first model of how ultrafine carbon-based particles interact with the lung tissues. Researchers created a 3D lung cell model system to investigate how carbon-based combustion byproducts behave as they interact with human epithelial tissue.