A group of scientists based in Hamilton has provided insights into the issue of black soot settling on residences near the city’s industrial zone. This problem, which has been ongoing for years, resurfaced in early July with what some residents described as the most severe fallout in recent times.
Sarah Styler, an environmental chemistry associate professor at McMaster University, and Grace Yao, a PhD candidate under Styler’s supervision, are part of a research project titled “What’s the Grime?” aimed at unraveling the nature of this phenomenon. Their study involved collecting samples across the city in 2024 and 2025, revealing that the soot consists of harmful substances typically associated with coal burning. Furthermore, elevated levels of dust and polycyclic aromatic hydrocarbons (PAHs) were detected in proximity to the industrial district in northeast Hamilton.
Collaborating with Environment Hamilton, Styler conducted the research funded by a $15,000 grant awarded by the university in 2024. Both Styler and Yao, residing in east Hamilton and Corktown respectively, have personal encounters with the soot issue. The research traced references to the soot back to the 1950s in historical news archives.
The study entailed collecting soot samples from 50 volunteers’ homes using sampling kits, which were analyzed at four-month intervals. Styler noted that more dust and toxic compounds were observed closer to the industrial area. The team also observed higher PAH levels during winter compared to summer.
Although the study focused on 13 different PAHs, Styler highlighted that other toxic elements may be present in the grime, which she described as a viscous substance. Despite resource constraints limiting a comprehensive analysis, coal combustion emerged as a significant source of the identified PAHs.
Styler emphasized that while the research team cannot pinpoint the exact industrial sources generating the PAHs, enhanced monitoring and analytical capabilities could facilitate this identification. The findings, according to Styler, confirm what residents in affected neighborhoods have long suspected – industrial emissions are likely responsible for the soot fallout.
Despite the apparent connection between industrial activities and the soot, local residents have expressed frustration over the lack of information from official channels. Efforts by the Ministry of the Environment, Conservation and Parks to investigate potential sources of the fallout are ongoing, with results expected to be shared publicly. Styler’s team plans to present their research findings at a community meeting on August 20 and aims to expand the study to include 200 volunteers, explore additional compounds present in the grime, and investigate effective cleaning methods.