Especially question 4,5 1. The figure above shows the environmental temperature

Question

Especially question 4,5

1.     The figure above shows the environmental temperature profile with wet and dry adiabatic lapse rate profiles superimposed. To approximately what altitude will a parcel of pollution rise adiabatically from the surface in unsaturated air if the parcel’s initial temperature is 25oC? What if its initial temperature is 30oC?

2.     In the figure above, determine the following quantities: a) inversion base height, b) inversion top height, c) inversion base temperature, d) inversion top temperature, e) mixing depth.

3.     Why do ozone mixing ratios peak in the afternoon, even though mixing depths are usually maximum in the afternoon?

4.     Summarize the meteorological conditions that tend to enhance photochemical smog buildup in an area.

5.     If emissions did not change with season, why might CO and aerosol particle concentrations be higher in winter than in summer?

Explanation / Answer

4.Photochemical smog is formed when nitrogen dioxide reacts in the presence of sunlight to form ozone. This ozone then reacts with various hydrocarbons to form various compounds and the result is a brownish yellow cloud of gas known as photochemical smog. The nitrogen dioxide is produced from various sources like especially vehicle exhausts and also burning of fossil fuels and industrial emissions.

Metereological conditions that promote photochemical smog are

Precipitation reduces the possibility of a smog formation because it washes all the pollutants in the air. Also the Also presence of sunlight is necessary so that the nitrogen reacts in the sunlight to form ozone.

Winds also affects the formation of photochemical smog because the presence of strong winds will displace the photochemical smog in the area and it gets replaced by the fresh air.

Also temperature inversion plays and important role in the formation of smog. In the absence of temperature inversion the surface gets heated and warm air rises to higher altitudes which reduces the possibility of formation of smog. Whereas if the temperature inversion is present, it prevents the air to rise and the polluted air is concentrated near the surface which makes it suitable for formation of photochemical smog.

Topography is also an important factor in controlling photochemical smog. The people living in valleys are more prone to photochemical smog because the temperature inversion is more stronger in valley which promotes the formation of smog as compared to the people living in mountains.

5. In winter the air near the surface is cold whereas the upper air is relatively warmer. Because the surface air is colder and hence more denser, it inhibits the rising of air. This condition promote the stability in the air and also promotes temperature inversion. Temperature inversion is that condition in which the temperature increases with elevation instead of decreasing. The temperature inversion is favourable for the formation for the accumulation of pollutants like CO and other aerosol particles near the surface. Therefore the pollutant concentration is higher in winter than in summer.

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