A team of researchers in Hamilton has answers to questions about the soot falling on neighbourhoods near the city's industrial sector. Working with volunteers to collect samples throughout the city, the researchers found the soot contains toxic chemicals consistent with coal combustion. They also found amounts of dust and polycyclic aromatic hydrocarbons (PAHs) were higher near the industrial area in northeast Hamilton. Living in east Hamilton, Styler said, she has first-hand experience with the soot; Yao said that's the case with her as well, in Corktown. Due to resource limitations, the study couldn't look at everything in the grime, Yao said, meaning it's possible other sources are contributing to the fallout.