Atmosphere Theme Report
Australia State of the Environment Report 2001 (Theme Report)
Lead Author: Dr Peter Manins, Environmental Consulting and Research Unit, CSIRO Atmospheric Research, Authors
Published by CSIRO on behalf of the Department of the Environment and Heritage, 2001
ISBN 0 643 06746 9
Regional Air Quality (continued)
Carbon monoxide across regional airsheds [A Indicator 4.4]
Blood absorbs carbon monoxide preferentially to oxygen and this can lead to tiredness and headaches. People with heart problems are particularly at risk (Table 4). The National Pollutant Inventory (NPI 1998, 2001) will soon be able to provide emissions information for Australia for carbon monoxide as well as many other gases. In the interim, the 1998 National Greenhouse Gas Inventory (AGO 2000) presents emissions of carbon monoxide for all of Australia since 1990, sector by sector (Figure 141), using a technique recommended by the Intergovernmental Panel on Climate Change (for updated information see http://www.greenhouse.gov.au/inventory/index.html ). The total from all sources for 1998 is given as 20 750 kt, much the same as in 1990.
Figure 141: National emissions of carbon monoxide by sector and year.
'Industrial Processes' and 'Waste' sectors were not estimated ; estimates for the 'Solvent and Other' sector were not applicable.
Source: AGO (2000)
Large and increasing contribution of carbon monoxide emissions from 'Agriculture' are shown in Figure 141. 'All Energy' sources have been decreasing over the past 10 years.
In rural and regional Australia, carbon monoxide levels are likely to be low, except in some larger towns, and only then in conditions of strong surface-based temperature inversions and light winds. Emissions from vehicles, wood fires or other combustion sources can produce elevated levels. Instances of elevated levels of carbon monoxide have occurred in Armidale and the Latrobe Valley, but these are rare. Throughout the 1980s, eight-hour average carbon monoxide concentrations in the Latrobe Valley of Victoria were less than 4 ppm (EPAV 1990), compared with the Air NEPM Standard of 9 ppm.
The current situation in regional non-industrial Australia is probably well represented by conditions in Bunbury, about 160 km south of Perth. Concentrations of carbon monoxide measured at the Bunbury monitoring station, plotted as monthly maximum eight-hour averages, shows an annual cycle with highest concentrations occurring in winter, associated with stable weather conditions (Figure 142). The highest concentration measured in 1999 was 2.7 ppm, which is 30% of the Air NEPM Standard.
Figure 142: Maximum eight-hour averages for each month for carbon monoxide in Bunbury, south-west Western Australia.
Source: Department of Environmental Protection, WA
The common sources of carbon monoxide are motor vehicles and fires. Since motor vehicle emissions of carbon monoxide are decreasing as the uptake of new standards occurs (see Urban air quality), it is most unlikely that carbon monoxide concentration in towns such as Bunbury will ever approach the Air NEPM Standards due to that source.
Whether carbon monoxide levels are elevated as a result of fires is uncertain. Levels are probably high in winter in centres such as Launceston and Armidale and warrant monitoring to test for compliance. In other regions such as Kalgoorlie and Mount Isa, there appear to be as yet no data from which to draw any conclusion.