The Control Method of Photochemical Smog Lee Jin-Young 2200938 Civil & Environmental System Engineering 2006 년 6 월 12 일

The Control Method of Photochemical Smog

Lee Jin-Young2200938

Civil & Environmental System EngineeringCivil & Environmental System Engineering2006 년 6 월 12 일

2006 년 6 월 12 일 Civil & Environmental System EngineeringCivil & Environmental System Engineering

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


Photochemical Smog

Utilization of gasoline increase with the increase of vehicle generation of smoke increaseThe 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 existedWarm and stagnant atmospheric conditions


Qualitative Relationship

PPL = photochemical pollution levelROG = concentration of reactive organic gasesNOX = concentration of oxides of nitrogen


Major FactorsThe spatial and temporal distribution of emissions of NOx and VOCS

(Both anthropogenic and biognic) The composition of the emitted VOCS

The spatial and temporal variations in the wind fields The dynamics of the boundary layer, including stability and the level of mixing


The chemical reactions of solar insolation and temperature The loss of ozone and ozone precursors by dry deposition The ambient background of VOCS, NOx, and other species in, immediately upwind, and above the regions of study


The Effects ofPhotochemical

Smog


Anatomy of a SmogNO2 + hv NO + O O + O2 O3

O3 + NO NO2 +O2

But, 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


ROG + O+ O3 R• + RCO + RO• + OH•

R• + O2 RO2•

RO2 • + NO RO• + NO2


Causes of Photochemical

Smog


The Control of Photochemical

Smog The approach to controlling smog has been to reduce emissions of its precursors(ROGX and NOX)


Propane


Toluene


n-butane


ConclusionWhen 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

Documents

The Control Method of Photochemical Smog Lee Jin-Young 2200938 Civil & Environmental System Engineering 2006 년 6 월 12 일