A group of researchers based in Hamilton has uncovered insights into the issue of soot deposition on neighborhoods in proximity to the city’s industrial zone. Over the years, residents have voiced concerns about a dirty, black residue covering their properties. The recurring problem resurfaced in early July, with some residents describing it as the most severe fallout in recent memory.
Sarah Styler, an associate professor specializing in environmental chemistry at McMaster University, and Grace Yao, a PhD candidate under Styler’s mentorship, are part of a study titled “What’s the Grime?” aimed at addressing this query. Conducting sampling activities across the city in 2024 and 2025 with the help of volunteers, the team discovered that the soot contains hazardous substances consistent with coal combustion. Moreover, elevated levels of dust and polycyclic aromatic hydrocarbons (PAHs) were identified particularly near the industrial hub in northeast Hamilton.
Collaborating with Environment Hamilton, Styler initiated the research project, which received a $15,000 grant from the university in 2024. Both Styler and Yao, residing in east Hamilton and Corktown respectively, have experienced firsthand encounters with the soot issue. Styler highlighted the long-standing nature of the problem, noting references to the soot in historical news archives dating back to the 1950s.
The study involved utilizing sampling kits distributed to 50 volunteer households across the city to collect soot samples periodically for analysis. According to Styler, the proximity to the industrial sector correlated with increased dust deposition and presence of toxic compounds. The team’s findings indicated higher PAH levels during winter compared to summer.
Styler emphasized that while the study focused on 13 PAH variants, other toxic elements in the grime remain unexplored due to resource constraints. Yao acknowledged the significance of coal combustion in generating the PAHs observed. Although the team refrained from pinpointing specific industrial sources of the PAHs, Styler suggested that with enhanced monitoring and analytical capabilities, such identifications could be feasible.
Styler anticipated that the research outcomes would not be surprising to residents most affected by the fallout, attributing the substance’s origins to industrial emissions near coke plants. Despite the community’s frustration over limited official information, the Ministry of the Environment, Conservation and Parks pledged to share test results and investigate industrial operations in Hamilton’s north end.
The researchers plan to present their findings at a community meeting on Aug. 20, with a manuscript under peer review awaiting publication. They intend to expand the study to include 200 volunteers, explore additional compounds in the grime, and assess effective cleaning methods.