Dubbed the Big Smoke, Toronto lived up to its nickname on Tuesday as a blanket of yellow-tinted smoke descended upon the city. The cause? Rampant forest fires raging in Quebec and northeastern Ontario. By nightfall, Toronto’s air quality had plummeted to become one of the world’s worst, even surpassing the pollution levels of Lahore, Pakistan, labeled as the most polluted city in 2022 by IQ Air, a global air quality tracker.
As the unsettling haze loomed and the moon turned crimson due to the wildfire smoke, health experts warned of the grim reality we may have to accept in the absence of substantial climate change mitigation efforts. Consequently, the risk of respiratory ailments, heart disease, cancer, and the subsequent strain on our already overburdened healthcare systems may become our new normal.
Jeff Brook, an associate professor at the University of Toronto’s Dalla Lana School of Public Health and Department of Chemical Engineering & Applied Chemistry (ChemE), emphasized the importance of wearing N95 masks to minimize the smoke’s impact. Even a standard surgical mask would offer some protection, he advised. Brook further recommended avoiding strenuous activities and ensuring windows and doors remain closed, acknowledging that any reduction in exposure to the hazardous air would benefit one’s health.
The situation was compounded by the fact that the smoke emitted by these fires produces PM2.5, which consists of fine particles smaller than 2.5 microns—about 30 of which could fit across a single hair strand. These tiny particles can easily penetrate deep into the lungs, and due to their size, they can even enter the bloodstream, triggering widespread inflammation that exacerbates heart conditions and potentially leads to various cancers.
Unfortunately, understanding the full extent of the damage caused by PM2.5 particles remains a challenge. Arthur Chan, an associate professor at ChemE, explained the complexity of these particles, noting that researchers are still uncovering the thousands of different compounds they contain and identifying the most toxic components.
Among the known components are PAHs, or polycyclic aromatic hydrocarbons, primarily formed during the incomplete combustion of organic materials like wood. PAHs have been classified as carcinogenic and mutagenic, with links to lung cancer and other forms of the disease due to their ability to induce DNA mutations.
Thus, the dangers posed by these particles are real, even if our understanding of their full impact remains limited. Ongoing research seeks to shed light on their composition and toxicity, providing crucial insights into the risks they pose to human health.