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ENV 541 Air Pollution and Its Control
Name: Brinay Prashain
1. If the environmental lapse rate is larger than the adiabatic lapse rate, what is
the stability condition? Is the air quality generally good or poor under that
condition? Briefly explain why.
If the environmental lapse rate is larger than the adiabatic lapse rate, the stability condition is unstable. Under this condition the air quality is generally poor because the air is less dense and warmer than its surroundings. The air under this condition will likely mix to form air pockets and clouds.
2. Write the equations for the formation of NO and NO2 due to the combustion
in an internal combustion engine. Can you predict the changes in
equilibrium compositions of NO and NO2 (i.e. will the total NOx
concentration and the ratio of NO/NO2 increase or decrease) as the
combustion temperature increases?
Formation of NO and NO2 in an internal combustion engine:
N
2
+ O
2
2NO 2NO + O
2
2NO
2
We can predict there will be a temperature increase, as there is an exothermic reaction. The NO is produced at a slower rate than the combustion process.
3. A coal fired power plant is planning to modernize its air pollution control
system. Is it to follow the current emission standard or the standard set when
the plant was first built?
According to the Clean Air Act, the power plant should follow the current emission standard or MACT (maximum achievable control technology). If a power plant is older, the EPA does take this into consideration by giving them time to modernize their systems to reduce harmful air pollution. Generally, these older plants have four years to
comply with the new standards. If needed, the regulatory committees of the state in which the plant is located can determine whether or not the plant needs more time to modernize (state implementation plans).
4. Does water increase or decrease global warming? Briefly discuss your
reason. Also, list one species that contributes to both global warming and
stratospheric ozone depletion.
Water will increase global warming as floods or droughts become more common and we have more days of heavier precipitation than normal. The water levels will rise but we will face extended dry periods in between the precipitation that will dissolve the water and cause a heavy layer of water vapor to sit in the atmosphere. A common
species known for both global warming and stratospheric ozone depletion is the homo sapiens (humans). Humans are greatly responsible for global warming and ozone depletion through mostly anthropogenic sources.
5. The 24-hour S02 NAAQS is 365 ug/ m3, Convert this to ppm at 100
degrees F and 130 Pa pressure.
Molecular weight SO
2
= 64.066g/mol
Concentration in ppm
= RT x concentration in ug m-3
pM
= (8.314) (336)
x 365
(130 x 1.0133 x 10
5
)(64)
= .0012 ppm
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