Air Pollution: Adverse Effects and Disease Burden

Abstract

At the time of the Workshop in 2017, the scientific evidence was certain: ambient air pollution, that is, contamination of outdoor air consequent to man’s activities, is a major cause of morbidity (ill health) and premature mortality (early death). While the rise of ambient air pollution is relatively recent, air pollution has probably had adverse effects on human health throughout history. In fact, the respiratory tract, which includes the nose, throat and lungs, has a remarkable system of defense mechanisms to protect against inhaled particles and gases. The use of fire for heating and cooking came with exposure to smoke, an exposure that persists today for the billions who use biomass fuels for cooking and heating. The rise of cities concentrated the emissions of pollutants from dwellings and industry and led to air pollution that was likely affecting health centuries ago. Continued industrialization and also electric power generation brought new point sources of pollution into areas adjacent to where people lived and worked. During the twentieth century, cars, trucks, and other fossil fuel-powered vehicles became a ubiquitous pollution source in higher-income countries and created a new type of pollution-photochemical pollution, or “smog”-first recognized in the Los Angeles air basin in the 1940s. The unprecedented growth of some urban areas to form “megacities, " such as Mexico City, São Paulo, London, and Shanghai, has led to unrelenting air pollution from massive vehicle fleets and snarled traffic and from polluting industries and coal-burning power plants. With population growth and urbanization, ever more megacities are anticipatesd; the current total of cities with a population over 10 million has now reached 31.