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This assignment provides answers to the following assignment description –
BACKGROUND:
On October 5 2006, the World Health Organization (WHO) released a new report on the health effects of environmental air pollution around the world. This is an except from CBC News.
MANILA, Philippines (AP) - The World Health Organization called on governments Thursday to improve air quality in their cities, saying air pollution prematurely kills two million people a year, with more than half the deaths in developing countries. Reducing pollution from particles that are too small to be filtered in the nose and throat and settle in the lungs could save as many as 300,000 lives every year, according to a statement issued by the WHO's regional office in Manila.
Reducing levels of those extremely small particles -- caused primarily by the burning of fossil and other types of fuel --could cut the deaths from air pollution by about 15 per cent, said Maria Neira, the WHO director for public health and the environment. It also could cut the global burden of disease from respiratory infections, heart disease and lung cancer, she said. Particulate matter pollution is considered the biggest health risk. But the WHO Air Quality Guidelines also recommended lowering the daily allowed limits for ozone.
That represents a challenge especially for developing countries with numerous sunny days when ozone concentrations reach the highest levels, causing respiratory problems and asthma attacks, WHO said. The guidelines also cut the sulfur dioxide limits. Many countries around the world do not have regulations for air pollution, which makes control virtually impossible. WHO said the new guidelines, which were established after worldwide consultation with more than 80 leading scientists, provide the basis for all countries to build their own air quality standards and policies supporting health. In Ontario, photochemical pollutants (smog) in ambient air are estimated to cause several thousand premature deaths per year, as well as increasing the rate and severity of respiratory diseases such as asthma, COPD, and acute bronchitis. This problem is especially severe in the Toronto-Hamilton region and throughout Southwest Ontario, including Kitchener-
Waterloo. Not surprisingly, ambient air pollution is considered to be a major problem in public health and the environment. The major focus of concern is generally on particulate matter (PM) and ozone, as a direct cause of health problems both from acute (short–term) exposures on bad air days and chronic (long-term) exposures over months and years.
ASSIGNMENT QUESTIONS:
Based on materials provided your PHS 604 course (particularly Lecture 7 ) and the associated Required Readings (plus any optional readings or papers that you elect to include), answer the following 5 questions:
1. Focusing on PM and ozone, briefly summarize the major sources of evidence from large-scale epidemiological studies that supports the conclusion that PM and ozone smog constituents in ambient air pollution contribute significantly to acute and chronic health effects in humans populations in developed countries such as Canada, the U.S. and the EU. Be specific about which types of health effects are associated with either acute or chronic exposure. Explain the basic distinction between different size fractions of particulates — coarse PM (PM10), fine PM (PM2.5) and ultrafine PM (PM<0.1).
2. Describe how various measures of exposure and dose can be applied to the determination of dose-response relationships for air pollutants and human health effects. Explain the distinction between ambient air pollution levels and personal exposures to air pollutants, and why this distinction is important. Explain the role of residential infiltration factors and individual time-activity factors in determining the personal exposure to air pollutants in humans. Using a chain of causality framework, discuss the relationships between ambient air exposure levels, personal exposure, inhaled dose, internal dose (in the lungs) and uptake of air pollutants into target tissues (e.g. lung airway cells, alveolar cells, macrophage cells, and bloodstream). Explain why the selection of an appropriate dose-metric for PM and ozone air pollution is important for public health.
3. Briefly describe the most plausible biological mechanism that might explain the ability of PM and ozone to cause similar respiratory and cardiovascular health effects, even though PM is a relatively unreactive physical particle and ozone is an active chemical gas. Discuss why PM and ozone are thought to have potential additive or synergistic dose effects when people are exposed to both substances at the same time. Explain how people's dietary patterns and nutritional status may affect their individual susceptibility to PM and ozone toxicity.
4. Discuss the recommended WHO Air Quality Guidelines for allowable for PM and ozone levels in ambient air in comparison to national air quality standards in specific countries (e.g. U.S. EPA). Explain why there needs to be different allowable levels specified for acute and chronic exposures. Discuss the meaning and significance of estimating the dose–response threshold for air pollutants, and explain the public health implications when no threshold can be determined by epidemiological studies.
5. Using a health promotion approach, discuss the strengths and weaknesses of current efforts by various federal, provincial, and local government health organizations to educate Ontario citizens about ways to avoid the hazards of ambient air pollution. Critically examine the use of the newly introduced Air Quality Health Index (AQHI) in Ontario as a visual and textual means of providing warnings about precautions to be taken on 'smog days' or 'bad air days', in comparison to the older Air Quality Index (AQI).