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Air pollution can occur naturally or be caused by human activities. [4] Air pollution causes around 7 or 8 million deaths each year. [5] [6] It is a significant risk factor for a number of pollution-related diseases, including heart disease, stroke, chronic obstructive pulmonary disease (COPD), asthma and lung cancer.
Looking down from the Hollywood Hills, with Griffith Observatory on the hill in the foreground, air pollution is visible in downtown Los Angeles on a late afternoon.. Air pollution is the introduction of chemicals, particulate matter, or biological materials into the atmosphere that cause harm or discomfort to humans or other living organisms, or damage ecosystems.
Air pollution is caused predominantly by burning fossil fuels, cars, and much more. [4] Natural sources of air pollution include forest fires, volcanic eruptions, wind erosion, pollen dispersal, evaporation of organic compounds, and natural radioactivity. These natural sources of pollution often soon disperse and thin settling near their locale.
Various definitions of pollution exist, which may or may not recognize certain types, such as noise pollution or greenhouse gases.The United States Environmental Protection Administration defines pollution as "Any substances in water, soil, or air that degrade the natural quality of the environment, offend the senses of sight, taste, or smell, or cause a health hazard.
The Air Quality Act of 1967 (Pub. L. 90–148) authorized planning grants to state air pollution control agencies, permitted the creation of interstate air pollution control agencies, and required HEW to define air quality regions and develop technical documentation that would allow states to set ambient air quality and pollution control ...
Indoor air pollution is a major health hazard in developing countries and is commonly referred to as "household air pollution" in that context. [5] It is mostly relating to cooking and heating methods by burning biomass fuel, in the form of wood, charcoal, dung, and crop residue, in indoor environments that lack proper ventilation. Millions of ...
Air pollution measurement is the process of collecting and measuring the components of air pollution, notably gases and particulates. The earliest devices used to measure pollution include rain gauges (in studies of acid rain ), Ringelmann charts for measuring smoke , and simple soot and dust collectors known as deposit gauges . [ 1 ]
In dry air, the adiabatic lapse rate (i.e., decrease in temperature of a parcel of air that rises in the atmosphere without exchanging energy with surrounding air) is 9.8 °C/km (5.4 °F per 1,000 ft). The saturated adiabatic lapse rate (SALR), or moist adiabatic lapse rate (MALR), is the decrease in temperature of a parcel of water-saturated ...