Dù nguy hiểm Khi các chất nguy cơ độc hại được thải vào khí quyển với tốc độ vượt quá khả năng của mình để giải tán họ bằng cách pha loãng và dòng không khí, sự tích lũy kết quả là ô nhiễm không khí. Nó có thể dưới dạng sương mù, bụi, sương mù (có thể ăn mòn), hay hút thuốc lá và có thể chứa các oxit lưu huỳnh và nitơ và các loại khí khác có thể gây kích ứng mắt, đường hô hấp, hoặc da và các chất khác có thể gây hại cho môi trường. | chapter four Airborne hazards The work is going well but it looks like the end of the world. S. Rowland co-discoverer of the CFC effect to his wife. Introduction When potentially noxious substances are discharged into the atmosphere at a rate that exceeds its capacity to disperse them by dilution and air currents the resulting accumulation is air pollution. It may take the form of haze dust mist which may be corrosive or smoke and may contain oxides of sulfur and nitrogen and other gases that may irritate the eyes respiratory tract or skin and other substances that may be harmful to the environment or to human health. Absorption may occur in amounts sufficient to cause acute or chronic systemic toxicity. Air pollution has been greatly underestimated as a cause of illness and death. In May 2000 acting Canadian Environment Commissioner Richard Smith quoted government statistics indicating that smog adversely affected the health of 20 000 000 Canadians and caused 5000 premature deaths annually in 11 major population centers. This is in comparison to 4936 deaths from breast cancer 3622 from prostate cancer 3064 from motor vehicle accidents and 665 from malignant melanoma. Air pollution obviously is an important health hazard. Types of air pollution Air pollutants may be gaseous or particulate in nature and particulates may be either solid or liquid. Smog is a combination of air pollutants. Gaseous pollutants These are derived from materials that have entered into chemical reactions or combustion processes. They include carbon-based compounds such as hydrocarbons oxides and acids sulfur compounds such as dioxide trioxide 2001 CRC Press LLC and sulfides nitrogen compounds ammonia amines oxides and halogenated substances organic and inorganic halides . Particulates Particle or droplet size may range from to 100 microns in diameter. The smaller particles are referred to as aerosols and can remain suspended scattering light and behaving much like a gas. Below 10 .
