A study on air  emissions from installations of oil refining in Canada identified in the atmosphere some potentially carcinogenic compounds that may affect human health. The information was used to create a tool to assess the limits of pollutant emissions. Among the many toxic pollutants in the atmosphere, the chemistry of benzene is one of the most serious threats to human health according to a study that involved University of Ottawa, Ryerson University and the University of Waterloo. From this study - published in the January 2008 issue of Journal of Toxicology and Environmental Health, "- researchers have created a

classification tool for reducing emissions on the basis of their estimates of the effects of air pollutants on health. This model, called the Health Effects Indicators Decision Index II or HEIDI II, classified as carcinogenic air contaminants emitted by the 20 oil refineries in Canada. Air concentrations of pollutants were measured for 20 geographical areas around each refinery. The rate of air pollutants were compared with data on the toxicity of volatile components identified by Health Canada and the U.S. Agency for environmental protection. These levels of toxicity were then applied to populations of children, adults and seniors. HEIDI II was able to predict the health impact of each substance emitted. According HEIDI II, the worst category of contaminants, which would require legislation, are carcinogenic compounds emitted into the air such as benzene, toluene, xylene, and polycyclic aromatic hydrocarbons (compounds from combustion sources such as barbecues, incinerators, and forest fires), some of these pollutants are emitted at levels of concern. HEIDI II was also able to test different scenarios such as the influence of solar light, which affects the speed at which the chemicals degrade in ultraviolet light, and the influence of emissions below the thresholds of regulations. This research has been used to inform the National Framework for reducing emissions of oil refineries (NFPRER). The NFPRER helps communities and environmental organizations to establish ceilings for emissions of air pollutants from oil refineries. The objective is to improve air quality and help reduce the negative impact on health, including respiratory tract and chronic diseases caused by toxins volatile. Today, the team at Ryerson University is working with an agency in Quebec to examine the effects on the health of an oil refinery in Montreal. In this study, the researchers analysis based on postal codes, correlating areas of high pollution with visits to hospitals for emergency pollution-related diseases such as childhood asthma. The findings of this survey will be subsequently published in the journal Environmental Health Perspectives. "