June 12-2006 Term project 20061/15
The Control Method of Photochemical Smog
Lee Jin-Young2200938
University of IncheonUniversity of IncheonDepartment of Civil & Environmental System EngineeringDepartment of Civil & Environmental System Engineering
June 12-2006 Term project 20062/15
Contents
• Introduction ⑴ Photochemical smog • Main subject ⑴ Qualitative relationship ⑵ Major factors ⑶ The effects of photochemical smog ⑷ Anatomy of a smog ⑸ Causes of photochemical smog• Conclusion ⑴ The control of photochemical smog
June 12-2006 Term project 20063/15
Photochemical Smog
Increase of gasoline use is one of the major cause of smog
generation
The term smog was used to describe the glaring bluish-brownish,
ozone-laden haze that enveloped the basin from late morning to
mid-afternoon when a certain combination of weather condition
existed
Warm and stagnant atmospheric conditions
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Qualitative Relationship
PPL = photochemical pollution levelROG = concentration of reactive organic gasesNOX = concentration of oxides of nitrogen
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Factors responsible for photochemical smog
The spatial and temporal distribution of emissions of NOx and VO
CS
(Both anthropogenic and biogenic)
The composition of the emitted VOCS
The spatial and temporal variations in the wind field
The dynamics of the boundary layer, including stability and the le
vel of mixing
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The chemical reactions of solar isolation and temperature
The loss of ozone and ozone precursors by dry deposition
The ambient background of VOCS, NOx, and other species in, immediately upwind, an
d above the regions of study
Factors responsible for photochemical smog
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EFFECT OF PHOTOCHEMICAL SMOG
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Anatomy of a Smog
NO2 + hv NO + O
O + O2 O3
O3 + NO NO2 +O2
Equation explain the diffusion of NOx in presence of light energy and formation of
ozone.
While the presence of NO2 is required to form O3, the nitro dioxide photolytic cycle
by itself does not generate net ozone, and can’t explain ozone accumulation
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ROG + O+ O3 R• + RCO + RO• + OH•
R• + O2 RO2•
RO2 • + NO RO• + NO2
Anatomy of a Smog
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Causes of Photochemical Smog
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The Control of Photochemical Smog
The approach to controlling smog
has been to reduce emissions of
its precursors(ROGX and NOX)
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Propane
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Toluene
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n-butane
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Conclusion
Stagnant of air is important of photochemical smog
Light energy is play vital role for the formation of ozone
When ROG/NOX is nearly between 5 and 6,the two species have equal
rates of reacting with the OH•
If this ratio is much larger than 6, there is a shortage of NO that can be
oxidized to NO2 and ozone production is controlled by the amount of NOX
available
On the other hand,when ROG/NOX is on the other of 5 or less,the ready
availability of NOX makes the formation rate of ozone dependent on ROG