The impact of traffic congestion during rush hours due to air pollution was estimated in terms of mortality and economic cost by researchers at the Harvard Clean Air Research Center and ACE Center. While other studies have examined on the effects of traffic emissions, the economic cost of traffic congestion has typically been estimated in terms of time wasted. In this study, researchers focused on the public health impact of traffic-related air pollution, and its economic impact. Traffic congestion in the greater Toronto metropolitan area was estimated through a stochastic model based on commuting time data, and traffic emissions were estimated through EPA’s MOVES model for PM2.5, accounting for exhaust, brakes, and tires emissions. Results showed an impact of 206 deaths per year from all causes (of which 119 for cardiovascular mortality), resulting in an economic impact of $1.3 billion ($778 from cardiovascular disease). The health and economic impact of the peak morning period (7-8 am) was 59 times higher than that of the least congested period (2:00 am). These results can help the medical and urban planning communities to prepare for future trends.