Subtropical Two global air circulation patterns High Pressure meet at about the latitude of los Angeles, sending air down toward Cool Air Aloft the earth this air is warmed by compression and forms a lasting thermal inversion Inversion Layer- Warm Ai Cool Sea Breeze The san gabriel mountains to the east of los angeles act to deter winds that would help to move the air from this area It would be tempting to blame air pollution on the weather, but that would be self-defeating The real culprit is us Next, we will learn what the main pollutants are and how they come about
Two global air circulation patterns meet at about the latitude of Los Angeles, sending air down toward the earth. This air is warmed by compression and forms a lasting thermal inversion. The San Gabriel Mountains to the east of Los Angeles act to deter winds that would help to move the air from this area. It would be tempting to blame air pollution on the weather, but that would be self-defeating. The real culprit is us. Next, we will learn what the main pollutants are and how they come about
4. Carbon Monoxide Most of our serious air pollution is produced either directly or indirectly by the combustion of fuels Incomplete combustion of carbon leads to the formation of carbon monoxide: 2C+O2→2CO A prime source of Co is the gasoline-fueled, spark-ignited internal combustion engine, where the burning of gasoline takes place at high pressure and temperature but not in an over-abundance of oxygen Motor vehicles account for more than 50% of the carbon monoxides In Los angeles County, there are over 3 million cars and more than 8000 tons of co emitted every day from internal combustion engines( about 5 pounds per vehicle per day)
4. Carbon Monoxide Most of our serious air pollution is produced either directly or indirectly by the combustion of fuels. Incomplete combustion of carbon leads to the formation of carbon monoxide: 2C + O2 → 2CO A prime source of CO is the gasoline-fueled, spark-ignited internal combustion engine, where the burning of gasoline takes place at high pressure and temperature but not in an over-abundance of oxygen. Motor vehicles account for more than 50% of the carbon monoxides. In Los Angeles County, there are over 3 million cars and more than 8000 tons of CO emitted every day from internal combustion engines ( about 5 pounds per vehicle per day)
Table 9.2 Major U.S. Air Pollutants(106 tons/yr) from various sources in 2003 CO NO VOC PM2.5PM10° Fuel combustion 0.5310.93 4.46 0.0 0.14 0.68 electric utilities Industrial fucl 1382222.780.17 0.15 0.31 combustion Other fuel combustion 3.00 0.60 0.73 0.88 0.43 0.46 Chemical and allied 0.33 0.330.10 0.22 0.02 0.05 product manufacturing Metals processing 1.420.290.090.07 0.03 0.14 Petroleum and 0.770.75 0 0.20 0.45 related industries Waste disposal and 1.85 0.030.14 0.43 0.36 0.39 recycling Highway vehicles 58.81 0.267.38443 0.13 0.19 Off-highway 24.45 0.44 4.10 2.57 0.28 0.31 Miscellaneous 14.35 0.12 0.31 6.4 4.45 20.06 Total 106.8915.9720.7316.06 6.19 23.04
Table 9.2 Major U.S. Air Pollutants (106 tons/yr) from various sources in 2003
Co is a colorless, odorless gas that is toxic at high concentrations Its toxicity stems mainly from its ability to form a stable compound with hemoglobin(血红蛋白) called carboxyhemoglobin. Co has an affinity for hemoglobin 200 times more than that of O2 Co tends to block the normal distribution of oxygen in the body and leads eventually to suffocation The effect of co on people is a function of concentration and duration of exposure 100 ppm for 10 hours-headaches and reduced ability to think clearly 300 ppm for 10 hours- nausea and possibly loss of consciousness 600 ppm for 10 hours-death can result 1000 ppm -unconsciousness occurs in 1hr and death in 4 hrs
CO is a colorless, odorless gas that is toxic at high concentrations. Its toxicity stems mainly from its ability to form a stable compound with hemoglobin (血红蛋白) called carboxyhemoglobin. CO has an affinity for hemoglobin 200 times more than that of O2 . CO tends to block the normal distribution of oxygen in the body and leads eventually to suffocation. The effect of CO on people is a function of concentration and duration of exposure. • 100 ppm for 10 hours — headaches and reduced ability to think clearly • 300 ppm for 10 hours — nausea and possibly loss of consciousness • 600 ppm for 10 hours — death can result • 1000 ppm — unconsciousness occurs in 1hr and death in 4 hrs
Table 9.3 U.S. National Ambient Air Quality Standards Pollutant Averaging Time Concentration Carbon monoxide(Co Primary 1 hour 35 ppm(40 mg/m) Primary 8 houra 9 ppm(10 mg/m Nitrogen dioxide(NO2), Annual 0.053ppm(100g/m3) Primary and arith. mean Sccondary a Not to be exceeded more than once a year. Sulfur oxides Primary Annual arith. mean 0.03ppm(80μg/m3) Primar 24-houra 0.14 ppm(365 ug/m econdarv 3-houra 0.5ppm(1300g/m3) Particulates(PM10 Primary and Annual arith. mean 50g Secondary Primary 24-houra 150g/m Particulates(PM2.5 Primary and Annual arith.mean° 15μgm3 Secondary Primary 24-hourd Ozone(O3), Primary and I-houre 0.12ppm(245μg/m3) Secondary 8-hour 0.08ppm(163gm3) Lead. Primary and Calendar quarter 1.5pg/m3 Secondary
Table 9.3 U.S. National Ambient Air Quality Standards a Not to be exceeded more than once a year