Air Pollution: Sources, Control Methods, and Impacts

Q1) Interpret different adiabatic lapse rates at stable or unstable condition (from the Figure below)?

•The ease with which pollutants can disperse vertically into the atmosphere is largely determined by the rate of change of air temperature with altitude. For some temperature profiles, the air is stable, that is, air at a given altitude has physical forces acting on it that make it want to remain at that elevation Stable air discourages the dispersion and dilution of the pollutants. For other temperature profile, the air is unstable.

Q2)a) write the different control methods for gaseous pollutants . Describe briefly?

Absorption involves the transfer of a gaseous pollutant from the air into a contacting liquid, such as water

b) Write the source reduction? Explain the air pollution status in KSA.

source reduction is an approach to reduce , eliminate or prevent pollution at its source .Controlling automobile pollution by using better fuel. 

  Q3) temperature inversion represent the extreme case of atmospheric stability. Creating a virtual lid on the upward movement of pollution. Briefly the different types of inversions?

The subsidence inversions are the result of the compressive heating of

descending air masses in high pressure zones.

frontal inversion is created when a cold air mass passes under a warm air

mass, these are short lived and tend to be accompanied by precipitation.

Q5. The Fissure Group has a power plant industry that emits SO₂. The industry has a stack containing an effective height of 280 m. The capacity of coal-fired power plant is 1000 MW (10 kW) having 45% efficiency. The plant can emit SO2 at the legally allowable rate of 0.52 lb SO2 per million Btu of heat into the plant. An anemometer on a 10 m pole measures 2.7 m/s of wind and it is a cloudy summer day. Predict the ground level concentration of so₂, 4 km directly downwind.

Here, 1 kWh = 3412 Btu; Input Power = Output Power/ Efficiency.

Input power =

Q= =4.9ug so_2/s  

_{C(0,4) =}

Q4) some pollutants are unique to the indoor environments, others are indoor and outdoor. Briefly mention and describe the somewhat unique indoor pollutants? Also mention indoor air pollution in KSA.

Asbestos used for fireproofing and insulation

-Radon gas that seeps out of the soil and collects in house

-Biological pollutants such as bacteria, molds, animal dander, dust mites.

Q6. The Fissure Group established a power plant industry. It uses 270 m stack with inside radius 3 m? The ambient air temperature is always 20° to 30° C and wind's speed at stack height to be 7 m/s during summer. The exit velocity at stack gases is estimated at 14 m/s at a temperature of 135° C.

 a) Estimate the effective height of the stack if the atmosphere is stable (class E) with the temperature increasing at the rate of 3°C /km

 b) Estimate the effective height of the stack if the atmosphere is unstable (class B) with the temperature increasing at the rate of 2.5°C /km

C) An anemometer at a height of 9.8 m above the ground was installed close to the plant. The wind speed at an elevation of 9.8 m is 3 m/s. Estimate the wind peed an elevation of 200 m if the atmosphere is moderately unstable (class B).

F = gr² v_s(1-) =9.81 m/s²×3×14×(1-)=110.4 m⁴\s³

a)S=(+0.01 =(0.002 +0.01 ) K/m=0.0004/s²

^1/3=2.6(^1/3=88.6 m H = 270+88.6=358.6 m

b) x_f = 120 F^0.4=120(110.4)^0.4=789 m =93.77 m

H=93.7 +270= 363.7 m

c) uH = ua ()^P=3(=5.46 m/s