气体污染物的来源和类型.ppt

Atmosphere New words expressions monoxide n.一氧化物 dioxide n.二氧化物 nitrogen n.氮 toxicity n.毒性 volatile adj.挥发性的，不稳定的 evaporate v.（使）蒸发，消失 New words expressions respiratory adj.呼吸的 airborne adj.空气传播的 pesticide n.杀虫剂 perchloroethylene n.全氯乙烯 thermal inversion 逆温 catalytic converter 催化转化器 Air Pollutants Carbon monoxide Volatile organic compounds Particulate matter Sulfur dioxide Nitrogen dioxide Lead Ground-level ozone and photochemical smog Hazardous air pollutants Primary Air Pollutants Carbon monoxide Volatile organic compounds Particulate matter Sulfur dioxide Oxides of nitrogen Primary standards?provide public health protection, including protecting the health of sensitive populations such as asthmatics, children, and the elderly.? Secondary standards?provide public welfare protection, including protection against decreased visibility and damage to animals, crops, vegetation, and buildings. Units of measure for the standards are parts per million (ppm) by volume, parts per billion (ppb) by volume, and micrograms per cubic meter of air (μg/m3). Criteria air pollutantsNational ambient air quality standards Carbon Monoxide Carbon monoxide is produced when organic materials such as gasoline, coal, wood, and trash are burned with insufficient oxygen. The single largest source of carbon monoxide is the automobile. Volatile organic compounds VOCs are composed primarily of carbon and hydrogen. VOCs are either evaporated from fuel supplies or are remnants of fuel that did not burn completely. Volatile organic compounds The use of internal combustion engines accounts for the majority of VOCs released into the air, although refineries and other industries add to the total atmospheric burden. Consumer products such as oil-based paint, charcoal lighter, and many other chemicals are important. Particulate Matter Particulate matter consists of minute (10 micros and smaller) solid particles and liquid droplets dispersed into the atmosphere. Travel on roads, agricul