Transcript Air pollution

Chemistry
Meteorology
Air pollution ?
Diffusion
Aerosol
Transport
Gas
pollutant
Deposition
Ozone
hole
Acid rain
Visibility
reduction
Photochemical
Smog
출처: 위키피디아 Library of Congress CALL NUMBER LC-USW36-376, reproduction number LC-DIG-fsac-1a35072
출처: Martin Bernetti AFP/ Getty images
Increase of scale
Local scale
Emission
City scale
Transport
Regional scale
Global scale
Removal
1. Effects and sources of air pollutants
1.1 Definition of air pollution
오염물질이 인간, 동·식물 및 재산에 유해하거나 인간의 쾌적한 생활을
방해할 정도의 양으로 대기 중에 존재하는 상태
1.2 Air pollution Episodes
• Meuse valley :Belgium
December 1930
Severe three-day fog
60 people died
• Dorora: United States
October 1948
Four-day fog
20 persons died
• London smog: 1952
December 5-8, Four-day fog
4000 persons died
1956: clean air act
Smog=Smoke+fog
• LA smog: photochemical smog
Hydrocarbon, nitrogen oxides, sunlight
LA is located in low basins surrounded by mountains
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1.3 General listing of air pollutants
1) Concentration Units
1ppm: 1 volume of gaseous pollutant/106 volume (pollutant+air)
g m-3
2) Classification of air pollutant
• General classification
Particulate matters
Sulfur containing compound
Organic compound
Nitrogen-containing compound
Carbon monoxide
Halogen compounds
Radioactive compounds
Photochemical oxidants
Other inorganic compounds
• Classification based on origin
Primary pollutant: those emitted directly from sources
ex) SO2, CO
Secondary pollutant: those formed in the atmosphere by chemical
reactions
ex) NO2, O3
1.4 Particulate matters (Aerosol)
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Definition: 대기 중에 부유하고 있는 액상과 고체상의 입자들
Size: 0.0002m-500m
Particles less than 0.1 m : Brownian motions
Particles between 0.1 and 2m: removed by rainout and washout
Particles larger than 20m: large settling velocity
removed from the air by gravity and inertial processes
Measurement: high volume sampler, PM10 sampler
TSP: total suspended particulate matter
PM10: the particulate matter which diameter is less than 10 m.
Damage to respiratory organ : fine particle (d<2.5m)
Visibility reduction : principally affected by fine particles
Aerodynamic diameter: the diameter of a sphere of unit density (1g
cm-3) that has the same terminal gravitational settling velocity in still
air as the actual particle in question
1-5 Carbon monoxide
Colorless, odorless gas
A lifetime of 2 to 4 months in the atmosphere
Natural source: oxidation of methane, biomass burning
Anthropogenic source: vehicle
minor role in photochemical reaction leading to ozone
formation
• Effect on health: reduce the oxygen-carrying capacity of the
blood
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1-6 Sulfur oxides
• SO2 (sulfur dioxide), SO3 (sulfur trioxide)
• SO2: nonflammable, nonexplosive, colorless gas
• SO2 -> Sulfuric acid
SO2 ( g )  SO2 (aq)
SO 2 (aq)  H 2 O  HSO3  H 
HSO3  SO32  H 
SO32  H 2 O  SO42  2 H 
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Acid rain (한반도 pH ~5, Cl-> SO42-> NO3- : 2012 대기환경연보)
𝑝𝐻 = −𝑙𝑜𝑔10 [𝐻 + ] : Acid rain pH<5.6
Long range transport
Sulfate: pronounced reduction in visibility
1.7 Effects of hydrocarbons, Oxides of nitrogen,
photochemical oxidants
1-7-A Hydrocarbon (탄화수소)
• Organic compounds composed of hydrogen and carbon
• Alkanes (CnH2n+2): RH ex) Methane (CH4), ethane (C2H6)
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R alkyl radical (CnH2n+1)
• Alkenes (CnH2n) :double bond
• Alkyne (CnH 2n-2): triple bond
• Aromatics : Benzene (C6H6), Toluene, Xylene
• Hydrocarbons, in combination with the oxides of nitrogen in the
presence of sunlight, form photochemical oxidants
• No direct adverse effects upon human health
• Radical: 적어도 한 개 이상의 쌍을 이루지 못한 전자를 갖고 있는
원자나 분자
• Ex) Alkyl radical CnH2n+1
• VOCs: volatile organic compounds
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The entire set of vapor phase atmospheric organics excluding
CO and CO2
1-7-B Oxides of nitrogen
• Nitric oxide (NO), Nitrogen dioxide (NO2), nitrous oxide (N2O),
NO3, N2O3, N2O4, N2O5
• NOx: NO+NO2
• NOy: the sum of the reactive oxides of nitrogen and all other
compounds that are atmospheric products of NOx.
• NOx, HNO3, HNO2, nitrate radical (NO3), N2O5, PAN (N2O, NH3는
아님)
• NO2: the highest concentration in ambient air
Absorbs visible light
Photochemical smog
Nitric acid (HNO3) -> acid rain
1-7-C Photochemical oxidants
• Ozone(O3), Peroxyacetyl nitrate (PAN), Hydrogen peroxide (H2O2),
formic acid (HCOOH) etc
• The products of atmospheric reactions involving VOCs, NOx and
radical and sunlight
• VOCs: volatile organic compounds
• Secondary pollutant
• Photochemical smog: high concentration of photochemical
oxidants
Marked reduction in visibility
Brownish sky
1-8 Sources of air pollutants
• Emission inventory : the study conducted to determine the
emission of particular pollutant done through the use of emission
factor
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emission factor: typical emissions that are emitted by a
particular source type based on the specific pollutant, type of
process, age, size, type of control technology.
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Major anthropogenic sources: transportation, fuel combustion
(stationary source), industrial process.
대기환경연보 2012
대기환경연보 2012
대기환경연보 2012
1-9 Global issues related to air pollution
• Acid rain, global warming, stratospheric ozone hole
1) Global warming
• Greenhouse effect: 대기가 태양의 단파복사를 거의 투과시키고
지구의 장파복사는 흡수 재 방출시킴으로써 지표면의 온도를 지구
복사평형온도보다 높게 만드는 효과
• Greenhouse gas : water vapor, carbon dioxide, methane, nitrous
oxide (N2O), CFCL3 CF2Cl2
• Kyoto protocol: International framework convention on climate
change with the objective of reducing greenhouse gases in an
effort to prevent anthropogenic climate change
• Signed in 1997
• Entered into force in 2005
• Industrialized countries (37) reduce collective emissions of
greenhouse gases by 5 % against 1990 levels over the five-year
period 2008-2012.
• CO2, CH4, N2O, HFC, PFC, SF6
2) Stratospheric ozone hole
 The presence of ozone in the lower stratosphere produces a very
beneficial effect by absorbing a significant amount of the short
wavelength ultraviolet radiation.
 Ozone hole in the stratosphere over Antarctica in spring (October)
 Montreal protocol (1987) : International agreement among nations
designed to protect the ozone layer by phasing out the production
of a number of substances (CFCs) believed to be responsible for
ozone depletion.
대기환경 연보 2012
대기환경 연보 2014
대기환경 연보 2014
연도별 SO2 와 NO2의 연평균 농도분포
대기환경 연보 2014
연도별 O3 와 CO의 연평균 농도분포
대기환경 연보 2014
연도별 PM-10 연평균 농도분포
대기환경 연보 2014
주요도시의 월평균 농도
대기환경 연보 2012
대기환경 연보 2012
대기환경 연보 2012
대기오염 관련 Web Site
국내 site
• Library.me.go.kr: 환경부 지식 포털
• www.nier.go.kr: 국립환경과학원
• erip.nier.go.kr: 환경연구종합정보 서비스
외국 site
www.epa.gov