Air pollutants derived from energy-related activities, primarily the combustion of fossil fuels (heating oil, coal, natural gas, gasoline, diesel fuel), are responsible for 82% of carbon monoxide emissions, 57% of SO2 emissions, 90% of NOx emissions, and 62% of VOC emissions9 . What follows is a description of the relationship between air pollutants and health. The link between air quality and health has long been established. In times past, when woodstoves and fireplaces provided indoor heating, the resulting respiratory illness required people to sleep propped-up by pillows. In 1952, a single smog event in London, England, characterized by very high concentrations of sulphur aerosols from the burning of coal as residential and commercial heating fuel, caused over 4000 deaths. This event and others in major cities across the world have led to the implementation of various measures to reduce the air pollution and therefore decrease the number of deaths. These measures however, have not eliminated mortality due to air pollution. In Canada, at least 5000 deaths are attributed to air pollution annually with over 2000 deaths in Ontario alone. In urban areas respiratory allergic diseases such as rhinitis and bronchial asthma appear to be on the increase worldwide. In Canada, the rate of asthma among children went from 2.5% in 1978 to 11.2% in 199510 (Figure 2). In Ottawa, it is estimated that air pollution is responsible for over 100 premature deaths/year, around 700 hospital admissions, over 900 emergency room visits, and around 65 million dollars are spent annually in respiratory and cardiovascular problems11 . In Toronto, approximately 35% of excess summer-time respiratory hospital admissions occur in children under 2 years of age12 . Unfortunately, there are not comparative figures for Ottawa13 . It is believed that air pollution causes sensitization of the airway resulting in high incidence of respiratory illnesses. The most vulnerable populations are children, the elderly, and those with underlying illnesses, particularly heart and lung diseases, such as asthma. Between 5 and 8% of Canadians are asthmatics and this number is growing15 particularly among children. Children are physiologically and anatomically at greater risk to air pollution than adults because of their growth rate. Children's lungs grow from 3 square metres at birth to 75 square metres by adulthood. Most of the pulmonary alveolar development continues into late childhood. The growing tissue is the most vulnerable to pollution. Children breathe in and out more rapidly than adults: every minute they exchange more air per kilogram of body weight than most adults. Hospital admissions due to respiratory problems for children have increased by 28% between1980 and 1990 . Adults over 45 years old are also vulnerable. These two groups currently represent 55% of Ottawa's total population. The vulnerability of our senior populations is also of concern given that their number will double by 2020. Consequently, the impact of air pollution to human health will be much greater in decades to come. Of all the air contaminants, diesel fuel particulate matter may be responsible for 70%-89% of total cancer risk caused by air pollution . It is estimated that diesel particulate matter may cause 13,600 cases of cancer in Canada. Air pollution has also been linked with reduced weight in newborns and to immunodeficiency. Some researchers note that there is a likelihood of other impacts that still need to be discovered. Recent research in California has shown evidence that air pollution not only triggers asthma attacks, but may in fact be a causal source of the illness . Depending upon the contaminant or its synergistic effects with other compounds, air pollution causes a range of other illnesses including decreased breathing capacity, eye irritation, decreased immune function, chronic respiratory, and chronic diseases and death. Previously, Canada had stood as a leader in air quality, particularly in its role in the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer. Canada acted swiftly to implement, enforce and update regulations to stop the use of most chlorofluorcarbons and other substances that destroy the upper atmosphere ozone layer that prevents excessive ultraviolet radiation. Due to continuous budget reductions at the federal level, Canada has become a country with the worst air emission records among the thirty members developed countries. Its air quality objectives have not changed since the 1970's. A 2004 report from the Organization of Economic Cooperative Development cited Canada as having one of the worst records for air emissions, specifically particulate matter and ground level ozone. On most days, the air quality in Ottawa is good to very good, but during the increasing number of summer smog episodes, it is poor to very poor. As the City's population increases, we will see a rise in the number of cars and trucks on our roads, currently above 0.5 million , both for personal transport and to supply goods and services to a larger population. Although improvements to vehicle efficiency and emissions will continue, more vehicles will still result in increased levels of air contaminants. The air quality challenges we face today will be aggravated by climate change with a likely two-fold increase in intensity of impact by 2020. A detailed description of our key air quality indicators, their trends in our environment and impacts on human and environmental health are presented in Annex 1. A brief description follows:
9 Environment Canada, forthcoming. National Emissions Inventory of Criteria Air Contaminants. Ottawa. National Indicators and Reporting Office, Environment Canada from the 2000 data |
Official site of the City of Ottawa
