大学精品课件：环境污染7年制预防医学.ppt

1、 Preventive medicine ,公共卫生学院环境卫生学教研室 http:/www.gxmu.edu/,第二节 环境有害因素对健康的危害 四、环境污染及对健康的危害,Qingqing Nong Department of Environmental Medicine,中国经济发展伴随严重环境污染问题,日益增多的 生活拉圾,工业污染 导致水养鱼类的 大量死亡,烟头小 也是污染源,酸雨腐蚀的 森林,恕吼,据中国新华社报导：,引 言,由于人为或自然的原因，使环境中污染物的量超出了环境的自净能力，造成环境质量下降或恶化，直接或间接地影响健康，称为环境污染,环境污染 environment p

2、ollution,由严重的环境污染引起的地区性疾病称公害病。必须得到法律、医学和有关政府部门认可，方可确定为公害病。如水俣病等。,公害病 public nuisance disease,1.直接危害 （1）急性中毒 当大气污染物的浓度在短期内急剧增高，使周围人群吸入大量污染物可造成急性中毒。,重庆开县天然气井喷事件,(一)大气污染对健康的危害,主要由烟雾事件和生产事故引起,烟雾事件 煤烟型烟雾（coal smog）事件 光化学烟雾（ photochemical smog）事件,There are two types of ambient air pollution as defined by

3、their different sources : coal smog and photochemical smog,In the great “Smog Disaster“ in London in 1952, four thousand people died in a few days due to the high concentrations of pollution. A dense smog caused by heavy coal combustion during the winter of 1952.,煤烟型烟雾事件,按烟雾形成原因分类 形成 主要污染物 举例 煤烟型烟雾事

4、件 煤烟和工业废气 烟尘、 马斯河谷烟雾事件 大量排入大气， 硫酸雾 多诺拉烟雾事件 不能充分扩散所致 SO2,伦敦烟雾事件,光化学型烟雾事件,按烟雾形成原因分类 形成 主要污染物 举例 光化学型烟雾事件 汽车尾气中的氮氧 臭氧、醛类、 美国洛杉矶 化物和挥发性有机物 过氧酰基硝酸酯 光化学烟雾事件 在日光紫外线照射 下经光化学反应形成,Photochemical smog is the chemical reaction of sunlight, nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the atmosp

5、here and forms a mix of inimicial chemicals including ozone, and PAN (peroxyacytyl nitrate)，acrolein that can be very dangerous.,Automobile exhaust is the major source of photochemical smog in most urban areas. One of the most important of these is ozone (O3) . It is a strong oxidant and can destroy

6、 lung tissue and chlorophyll in plants. Other photochemical oxidants include peroxyacetal nitrate (PAN) and acrolein, both of which are strong oxidants and can damage materials. PAN is also a severe eye irritant.,Smog Disaster of Los Angeles,光化学烟雾事件,What is the difference between coal smog and photo

7、chemical smog ？,煤烟型烟雾事件与光化学型烟雾事件的比较,生产事故和意外事故引发的急性中毒事件,印度博帕尔毒气泄漏事件,咽炎、气管炎、 Chronic Obstructive Pulmonary Diseases,（2）慢性危害,环境中有害物质以低浓度、长时间反复作用于机体所产生的危害。,1. 慢性炎症,2.变态反应,3.非特异性疾病多发,4.致癌作用,如甲醛、SO2、某些洗涤剂,如苯并芘、石棉、砷、镍、铬,唾液溶菌酶含量下降 SIgA减少,The diseases and symptoms of illnesses associated with specific air po

8、llutants range from eye and throat irritations, respiratory infections, and bronchial asthma to cardiovascular disease, lung cancer, and genetic mutations.,2.间接危害 (1）温室效应 (2）形成酸雨 （3）破坏平流层的臭氧层,Air pollution can also create acid rain, depletion of the ozone layer and global warming which are major glo

9、bal environmental concerns.,Climate change,The worlds climate is controlled by many factors. One of the major factors is Earths temperature. During the late 1970s and into the 1980s, scientists became concerned that increases in atmospheric carbon dioxide levels could cause Earths temperature to inc

10、rease, which could lead to vast changes in weather patterns.,Greenhouse effects,Greenhouse effects,Carbon dioxide traps some of the infrared radiation that escapes from the Earth, making the Earth warmer, much as the glass does in a greenhouse. The process has been termed the greenhouse effect. Meth

11、ane, chlorofluorocarbons (CFCs), and nitrous oxide (N2O) are also greenhouse gases.,infrared radiation,make the Earth warmer,2.陆地和海洋生态系统受到影响，植物群落及浮游生物发生改变,3.气温增高有利于病原体繁殖，使某些传染病、寄生虫病及食物中毒发病率,1.使两极冰川融化，海平面上升，陆地面积减少。,温室效应的影响,1. It give rise to water- and food-borne diseases; vector-borne and rodent-bor

12、ne diseases; or food and water shortages. 2.Temperature-related illness and death could increase. 3. It increases human exposure to spores and moulds. Consequently, allergic diseases could increase. 4. This could result in melting of the ice caps, rising sea levels, coastal flooding, shifting of cro

13、p-producing regions, and adverse impacts on populations of humans and other life.,Negative impacts of Greenhouse effects,Acid rain,Acid rain is rain or any other form of precipitation with a pH of less than 5.6. When a pollutant, such as sulfuric acid combines with droplets of water in the air, the

14、water (or snow) can become acidified .,危害1,酸雾刺激呼吸道并发生慢性炎症，对婴幼儿影响更大,酸雨 acid rain,危害2,水体酸化使水生生物生长受到影响，鱼群减少，水生植物受影响，影响水体自净,酸雨 acid rain,Effects of acid rain on aquatic systems are more established. Thousands of lakes can no longer support the growth of fish, and other aquatic life (frogs, plants, etc.)

15、 is also affected. The lowered pH can also change the speciation of toxic metals in the water and sediment, making them more available to the organisms.,危害3,酸雨能腐蚀建筑物，破坏输水管网，使水质恶化。,酸雨 acid rain,The acids are very corrosive and can attack many materials. Forests around the world are dying at an alarmi

16、ng rate, due in part to acid rain. Some areas have seen 50 percent or greater mortality of trees, and even higher decreases in survival of new saplings.,酸雨腐蚀雕刻,酸雨腐蚀的森林,酸 雨,Stratospheric ozone depletion,Ozone is mainly broken down by chemicals called ChloroFluoroCarbons （CFCs ）and also by nitrogen ox

17、ides.,skin cancer cataracts,ozone depletion,The release of chlorofluorocarbons and other atmospheric pollutants depletes stratospheric ozone, which in turn increases human exposure to ultraviolet radiation, causing skin cancer and cataracts in humans or other living organisms.,后果：削弱臭氧层遮挡吸收短波紫外线的功能，造成 人群接触者皮肤癌和白内障等发病率的增加。,Stratospheric ozone depletion,QUIT,你真的要退出本课件吗？,是,否,