Although Air pollution is defined by the World Health Organization as the "the world's largest single environmental health risk" and causes millions of premature deaths annually. Exposure to air pollution is associated with respiratory diseases as a result of (including asthma and changes in lung function), cardiovascular diseases, adverse pregnancy outcomes (such as preterm birth), and even death. In 2013, the World Health Organization concluded that outdoor air pollution is carcinogen to humans dispite In other words, air pollution is an invisible killer—may not always be visible, but it can be deadly.
The two major types of outdoor air pollution, smog and soot, come from cars and trucks, factories, power plants, incinerators, engines—anything that combusts fossil fuels such as coal, gas, or natural gas. becouse the Smog, or "ground-level ozone," occurs when emissions from combusting fossil fuels react with sunlight. instred of Soot, or "particulate matter," is made up of tiny particles of chemicals, soil, smoke, dust, or allergens, in the form of gas or solids that are carried in the air.However,as a results of from a recent study (published in the journal Science) show that in urban areas, chemicals contained in consumer goods such as personal care products, indoor cleaners, paints and pesticides now contribute as much to ozone and fine particulate matter as do emissions from the combustion of fossil fuels.
