Australia State of the Environment Report 2001 (Theme Report)
Lead Author: Professor Peter W. Newton, CSIRO Building, Construction and Engineering, Authors
Published by CSIRO on behalf of the Department of the Environment and Heritage, 2001
ISBN 0 643 06747 7
Liveability: human well-being (continued)
Transport demand, access and congestion (continued)
Public health and well-being is also threatened by pollutant emissions from road traffic. Emissions contribute to summer smog levels via volatile organic compounds and in winter to the buildup of particulate emissions, which particularly affect the vulnerable members of the community-the elderly, the very young and those suffering from respiratory illness. Table 40 shows possible health hazards from motor vehicle emissions (see Atmosphere theme report).
|Pollutant||Proportion emitted from motor vehicles||Impacts on human health|
|Carbon monoxide||Around 90% in summer and 70% in winter in Melbourne (EPA Victoria 1998). Diesel vehicles emit less than petrol vehicles||At high concentrations symptoms include headache, reduced mental acuity, vomiting, collapse, coma and death|
|Lead||Motor vehicles contribute around 90% of airborne lead in urban areas (ABS 1998)||Toxic effects include chronic renal disease, chronic anaemia and neurological disorders. Children are particularly susceptible|
|Nitrogen dioxide||Around 65% in summer and 60% in winter (EPA Victoria 1998). Diesel emits less than petrol vehicles||Can lead to respiratory infections, asthma, chronic obstructive airway disease and chronic lung damage|
|Ozone||Secondary pollutant not directly emitted from vehicles||Causes itchy and watery eyes, sore throats and nasal congestion. Also irritates the lower respiratory tract|
|Respirable particles||Up to 90% (by diesel vehicles) in some urban areas||Carries acidic gases and polycyclic aromatic hydrocarbons into the lungs. Can also trigger asthma attacks|
|Sulfur dioxide||Around 13% in both summer and winter (EPA Victoria 1998)||Aggravates existing respiratory conditions such as asthma and chronic bronchitis, increasing cough and mucous secretion. Also acts in combination with other environmental factors|
|Hydrocarbons (Benzene)||Around 50% in summer and 44% in winter. Vehicles without catalytic converters are high emitters of benzene||Benzene is a known carcinogen, linked to leukaemia|
|Hydrocarbons (Polycyclic aromatic)||Diesel exhaust is a rich source of polycyclic aromatic hydrocarbons (PAH)||Benzo(a)pyrene, a common constituent of PAH mixtures, is a major initiator of lung cancer|
AFigures are largely for Melbourne.
Sources: Institute of Engineers Australia cited in Brindle et al.(1999); EPA Victoria (1998).
GIS mapping of air pollutants against groups at risk (e.g. the very young and the elderly) reveals a significant number of neighbourhoods and zones of our cities where populations are at risk of exposure at above-average levels of pollutant emission (Newton 1997).
The amount of travel by households in cities is growing faster than growth in population, due to increased out-of-home activities and changes in work patterns. Travel is predominantly by car, due to the car's advantages for complex trips on tight schedules, and relatively low ownership and running costs. At the same time, road freight is increasing rapidly because of the growing numbers of goods, including construction materials for growing cities, and because of services provided to both households and business. Increasing vehicle kilometres by light commercial vehicles is of special concern. This increase in transport demand is leading to traffic congestion and to increased alienation of the natural and built environment as new road infrastructure and parking space is supplied. A wide mix of travel demand management strategies will be required. Some of these, such as allowing congestion to discourage traffic, may have adverse impacts in relation to pollution.
Motor vehicle transport is also imposing a high cost on community health and safety. While the number of car crashes is being contained, the human and financial costs are still high.
At the same time, air pollution is likely to increase in the short term, with increasing danger to the vulnerable members of the community on days when adverse weather conditions allow pollution to build up. Along highways, air pollution affecting both neighbourhoods and drivers is a special problem in congested conditions, which may also apply in smaller cities not yet affected by general air pollution caused by transport. The trend for children to be driven rather than walk is also a community health concern.
However, such costs need to be balanced by advantages of increasing community access to goods and services, and employment opportunities.