Additional Practice Questions for Chapter 5

Worksheet 5.4 Additional Practice questions for Chapter 5

1 The figure below shows emissions of NOx and VOCs in North America in 1990 and 2005.

(a) Identify NOx and VOCs. [1]

(b) Identify two possible sources of NOx and VOCs. [1]

(c) Describe the trends in NOx and VOCs as shown in the figure above. [3] (d) Suggest possible reasons for the difference in trends between the USA, Canada and Mexico. [3]

(e) Comment on the implications of changing levels of VOCs and NOx in the atmosphere. [3]

http://ga.water.usgs.gov/edu/acidrain.html

(a) Describe the distribution of acid precipitation as shown in the figure above. [3] (b) Suggest reasons for the distribution of acid precipitation. [3] (c) Explain why the effect of acid deposition is regional rather than global. [5]

1 (a) oxides of nitrogen e.g. nitrogen oxide and nitrogen dioxide; volatile organic compounds such as methane and ethane; [1] (b) petrol and oil; dyes / glues and inks; [1]

(c) emissions of NOx have declined overall from about 27mt (megatonnes) in 1990 to 21mt in 2005; the decline has been greatest in the USA, whereas Canada and Mexico have declined much less; air emissions of VOCs have decreased from 26mt in 1990 to about 20mt in 2005; greatest decrease is in the USA, the decline is lower in Canada and Mexico; [3] (d) greater enforcement of environmental legislation; Mexico’s Hoy no curcula policy reducing the number of cars in Mexico City; the use of cleaner fuel; greater use of public transport; [3]

(e) Both VOCs and NOx are decreasing slowly. Photochemical reactions between nitrogen oxides and VOCs in sunlight create ground level ozone. Ground ozone damages crops and forests, irritates eyes, can cause breathing difficulties in humans and may increase susceptibility to infection. Thus, there may be a decline in the level of ground level ozone – or at least its intensity – so a reduction in the impacts, including mortality rates (below a certain level). An increase of 10 ppb led to an increase in mortality rates in the USA of 0.52%, so a reduction in ozone might be expected to lead to a decreased mortality. [3]

2 (a) the most acidified areas (pH <4.3) are in the north-east USA in a belt from the Great Lakes to New York; acidification decreases away from this densely populated, industrial region; e.g. in the far north-east (New England) the pH is >4.5, in the south (Florida) it is 4.7 and in the West Coast region it is 5.3; [3] (b) concentration of industry in the belt between Chicago and New York; concentration of coal-fired power stations in the area; high density of population and vehicles in this region; prevailing winds carrying some of the pollutants north-eastwards from the sources of pollution; [3] (c) main impacts are regional rather than global because the main sources are localized; in particular, industrial regions in NW Europe, NE USA, the Earl River (China) and Damador

Valley (India) are or were major sources of SO2 and NOx; pollutants are carried by prevailing winds and deposited either as dry deposition close to the source of pollution or as wet deposition much further away; [5]