200 likes | 484 Views
Very serious in many countries. 代表性的空氣污染問題 都市尺度 : 煙霧 (smog) 區域尺度 : 酸雨、衍生性氣膠 、 黃砂長程傳輸 全球尺度 : 臭氧層破壞、全球變遷. Smog = Smoke + Fog. London Type Los Angles Photochemical smog. London smog. documented since the 13 th century widespread use of high-sulfur coal caused by meteorological conditions
E N D
代表性的空氣污染問題 • 都市尺度:煙霧(smog) • 區域尺度:酸雨、衍生性氣膠、黃砂長程傳輸 • 全球尺度:臭氧層破壞、全球變遷
Smog = Smoke + Fog • London Type • Los Angles Photochemical smog
London smog • documented since the 13th century • widespread use of high-sulfur coal • caused by meteorological conditions • radiation inversion • cycle of condensation on aerosols at low T (night), and evaporation at higher T (day) • contained the pollutants in a small volume • high concentrations of SO2 and particles over London • fog droplets provided the aqueous medium for SO2 SO42- http://www.bbc.co.uk/paintingtheweather/csv/painting/thames.shtml
Photochemical (LA) Smog • first observed in the 1940’s in Los Angeles, Calif. • occurred on hot days with bright sun • plant pathologists at UCR observed damage to plants in the LA basin area • in the lab: organics + NOx + sunlight O3 + “other products” • also observed for auto exhaust: NOx + HC’s • VOC and NOx emissions are “trapped” by thermal inversions and irradiated by sunlight http://maquinna.vsb.bc.ca/students/bclung02/Div05/ect/smogp.htm
O3 Concentration (ppm) NO2 NO Time (hours) Photochemical Air Pollution primary pollutants + hν secondary pollutants VOC + NOx + hν O3 + PAN + HNO3 + particles (PAN = peroxyacetyl nitrate CH3C(O)OONO2 ) NO2 + hν (λ<430 nm) NO + O O + O2 O3 *sole significant source of anthropogenic O3* NO + O3 NO2 + O2 (competing process) O3 forms when [NO] decreases
Acid Deposition • recognized in the 18th century • 1872: Robert Angus Smith described 3 types of rain regions in England • coined the term acid rain • oxidation of SO2 and NO2 acids • wet deposition (濕沉降) and dry deposition(乾沉降) • deposition is both local and 1000+ km away from primary source http://www.epa.gov/airmarkets/acidrain/#what
乾沉降:在沒有降雨、雪、霧等情況下產生的沉降乾沉降:在沒有降雨、雪、霧等情況下產生的沉降 濕沉降(酸雨):降雨、雪、霧等情況下產生的沉降 http://www.soton.ac.uk/~engenvir/environment/air/acid.buildings.html
Acid Deposition and Humans • Respiratory diseases • Toxic metal leaching • Damage to structures, especially containing calcium carbonate • Decreased visibility • Decreased productivity and profitability of fisheries, forests, and farms
Acid Deposition and Aquatic Systems • Fish declines • Aluminum toxicity • Acid shock • Eutrophication(優養化) of lakes or estuary
WHY CARE ABOUT ATMOSPHERIC AEROSOLS? Public health Chemistry Visibility Cloud formation Ocean fertilization Climate forcing
Effects of secondary aerosol • Health Effects : Particle pollution - especially fine particles - contains microscopic solids or liquid droplets that are so small that they can get deep into the lungs and cause serious health problems. Numerous scientific studies have linked particle pollution exposure to a variety of problems, including: • increased respiratory symptoms, such as irritation of the airways, coughing, or difficulty breathing, for example; • decreased lung function; • aggravated asthma; • development of chronic bronchitis; • irregular heartbeat; • nonfatal heart attacks; and • premature death in people with heart or lung disease. . Environmental Effects • Visibility reduction. • Environmental damageParticles can be carried over long distances by wind and then settle on ground or water. The effects of this settling include: making lakes and streams acidic; changing the nutrient balance in coastal waters and large river basins; depleting the nutrients in soil; damaging sensitive forests and farm crops; and affecting the diversity of ecosystems. • Aesthetic damageParticle pollution can stain and damage stone and other materials, including culturally important objects such as statues and monuments. • Change weather: Global warming, increase rainfall
World Bank, 1997: Urban air quality management strategy in Asia, Guidebook
World Bank, 1997: Urban air quality management strategy in Asia, Guidebook
World Bank, 1997: Urban air quality management strategy in Asia, Guidebook
World Bank, 1997: Urban air quality management strategy in Asia, Guidebook
World Bank, 1997: Urban air quality management strategy in Asia, Guidebook
World Bank, 1997: Urban air quality management strategy in Asia, Guidebook