A population-based cohort study in Metropolitan Vancouver found that long-term exposure to traffic-related air pollution, particularly black carbon, is associated with increased risks of coronary heart disease (CHD) hospitalization and mortality. The study included 452,735 individuals aged 45–85 years who lived in the area during the exposure period and had no prior CHD. Exposure to black carbon was linked to a 3% increase in CHD hospitalization and a 6% increase in CHD mortality after adjusting for age, sex, preexisting comorbidities, and other pollutants. The study also found linear exposure-response relationships between black carbon and coronary events. Black carbon, a marker for traffic-related fine particulate matter, was strongly associated with CHD mortality, with a 14% increase in mortality for an interquartile range elevation in black carbon concentration. The study suggests that traffic-related air pollution, particularly black carbon, may partly explain the observed associations between road traffic exposure and adverse cardiovascular outcomes. The findings highlight the importance of addressing traffic-related air pollution for evidence-based environmental policy and cost-effective interventions. The study used land-use regression models to estimate individual exposure to traffic-related pollutants, including black carbon, PM2.5, NO2, and NO, based on residential histories. The study also considered potential confounding factors such as neighborhood socioeconomic status and preexisting comorbidities. While PM2.5 showed no significant association with CHD hospitalization or mortality, black carbon and NO2 were more strongly associated with CHD mortality. The study's results suggest that reducing traffic-related air pollution could help mitigate the risk of cardiovascular disease.A population-based cohort study in Metropolitan Vancouver found that long-term exposure to traffic-related air pollution, particularly black carbon, is associated with increased risks of coronary heart disease (CHD) hospitalization and mortality. The study included 452,735 individuals aged 45–85 years who lived in the area during the exposure period and had no prior CHD. Exposure to black carbon was linked to a 3% increase in CHD hospitalization and a 6% increase in CHD mortality after adjusting for age, sex, preexisting comorbidities, and other pollutants. The study also found linear exposure-response relationships between black carbon and coronary events. Black carbon, a marker for traffic-related fine particulate matter, was strongly associated with CHD mortality, with a 14% increase in mortality for an interquartile range elevation in black carbon concentration. The study suggests that traffic-related air pollution, particularly black carbon, may partly explain the observed associations between road traffic exposure and adverse cardiovascular outcomes. The findings highlight the importance of addressing traffic-related air pollution for evidence-based environmental policy and cost-effective interventions. The study used land-use regression models to estimate individual exposure to traffic-related pollutants, including black carbon, PM2.5, NO2, and NO, based on residential histories. The study also considered potential confounding factors such as neighborhood socioeconomic status and preexisting comorbidities. While PM2.5 showed no significant association with CHD hospitalization or mortality, black carbon and NO2 were more strongly associated with CHD mortality. The study's results suggest that reducing traffic-related air pollution could help mitigate the risk of cardiovascular disease.