第一章绪论02课

1、8. 全球变暖和气候变化:Major Greenhouse Gases GasContribution to global warming (percentage)CO257CFCS25CH412N2O6全球平均气温的变化大气中二氧化碳含量的变化全球变暖产生的影响The importance of black carbon has only recently been recognizedThe IPCC (Intergovernmental panel on Climate Change ) has reached several important conclusions:The aver

2、age temperature of the earth has increased 0.3-0.6 (1995 was the warmest year on record) and sea level has risen 10-25cm in the last 100 years.A continued increase in temperature and sea level will occur. Various models suggest an increase in temperature of 1-3.5and a sea level rise of 15-95cm by th

3、e year 2100.There is a strong correlation between the increase in temperature and the amount of greenhouse gases present in the atmosphere.Human activity greatly increases the amounts of these greenhouse gases. 9. 臭氧层破坏:Ozone absorbs ultraviolet light and is split into an oxygen molecule and an oxyg

4、en atom:Oxygen molecule is also split by ultraviolet light to form oxygen atoms:Recombination of oxygen atoms and oxygen molecules allow ozone to be formed again and to be available to absorb more ultraviolet light:This series of reactions results in the absorption of 99% of the ultraviolet light en

5、ergy coming from the sun.Chlorofluorocarbons (CFCs) are strongly implicated in the ozone reduction in the up atmosphere. These reactions both destroy ozone. 19791986年TOMS测得的总臭氧全球平均值注：Dobson单位 将0C，标准海平面压力下，105m厚的臭氧 定义为一个Dobson单位19791986年总臭氧纬向平均值的趋势10. 室内空气污染吸烟的危害11. 中国城市的大气污染概况1999年全国重点城市主要大气污染物分布全国城

6、市空气质量分级比例 2002年，监测的343个城市中，117个城市空气质量达到国家二级标准119个城市空气质量为三级107个城市空气质量劣于三级与上年相比，空气质量达到二级标准的城市比例略有增加，劣于三级的城市比例下降了2个百分点不同空气质量状况下人口比例 特大、超大型城市空气污染明显重于中小城市，尤以人口规模在100200万的特大型城市空气污染最重空气中主要污染物二氧化硫和颗粒物浓度超标的特大、超大城市比例明显高于中小城市二、大气污染的影响1. 对人体健康的影响CO对人体健康的影响CO（10-6）对人体健康的影响510 对呼吸道患者有影响30 人滞留8h，视力及神经机能出现障碍40 人滞留8

7、h，出现气喘1201h接触，中毒，血液中COHb10%2502h接触，头疼，血液中COHb=40%5002h接触，剧烈心痛，眼花，虚脱3000 30min即死亡NO2对人体健康的影响NO2（10-6）对人体健康的影响1 闻到臭味5 闻到强臭味1015 10min眼、鼻受到刺激50 1min内人呼吸困难80 3min感到胸痛、恶心100150 在3060min内死亡250 很快死亡臭氧对人体健康的影响注：部分人群接触臭氧后肺功能下降突发性严重大气污染事故1952年12月伦敦烟雾事件中死亡人数与大气中烟尘和二氧化硫浓度的相关性2. 对植物的伤害注：二氧化氮浓度和暴露时间与植物死亡、叶器官损伤和新陈

8、代谢或生长影响之间的关系Source：Springer-Verlag and Prof. D. C. MacLean3. 对器物和材料的影响注：平均二氧化硫浓度和不同暴露时间与低碳钢的腐蚀之间的关系（19631964年9月，在芝加哥的七个地点进行的实验）Source：Air and Waste Management Association4. 对大气能见度的影响对大气能见度或清晰度有影响的污染物，一般应是气溶胶粒子、能通过大气反应生成气溶胶粒子的气体或有色气体，包括：总悬浮颗粒物（TSP）SO2和其它气态含硫化合物，在大气中以较大反应速率生成硫酸盐和硫酸气溶胶粒子NO和NO2，在大气中反应生成

9、硝酸盐和硝酸气溶胶粒子光化学烟雾，反应生成亚微米的气溶胶粒子 能见度与大气中颗粒物浓度的关系The most widely used equation for estimating visibility is the Koschmeider equation: where Lv is the visual range, the distance at which an average person can barely distinguish a dark object( such as a mountain or skyscraper ) against the sky. This equa

10、tion is an approximation, based on an average set of atmospheric particles. Use the equation to estimate the visual range when the particulate concentration is equal to the annual average and to the maximum 24-hour NAAQS for PM10.In the Grand Canyon and the surrounding area, on clear days, one can easily see mountains 100 miles away. What is the probable concentration of particles in the atmosphere when one can see that far?If the particle concentration in the atmosphere is increased by 1 ug/m3, what is the percentage decrease in the visual range if the initi