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
Urban Air Quality (continued)
Quality of monitoring system [A Indicator 3.14]
The Victorian EPA's internal business plan performance targets for data capture are:
- 90% overall capture of meteorological data at each station
- 90% overall capture of other data overall at each station
- 85% on each instrument.
EPA typically achieves over 90% data capture. The minimum acceptable level of data capture in Australia is 75% (NEPM Ambient Air Quality Monitoring Protocol Working Group 1998) and, as for Victoria, most instruments for most of the states meet this requirement. During 1999, for example, the lowest data recovery in south-east Queensland was 84% (for sulfur dioxide monitoring), and the lowest in Perth was 89% (haze monitoring). All jurisdictions will need to report formally on their performance as part of the Air NEPM (NEPC 1998).
The situation is less satisfactory for monitoring air pollutants that are not part of the NEPM (e.g. the lack of pollen monitoring). Monitoring of air toxics is satisfactory for certain substances (e.g. benzene) in some locations, but more monitoring will be needed. The particular air toxics to be monitored need to be worked out on the basis of the risk that each air toxic poses. Thus, the development of an agreed national protocol forms a continuing part of the work of Environment Australia (see http://www.environment.gov.au/airtoxics) and is likely to be incorporated into a future air toxics NEPM.
The Australian Bureau of Statistics has conducted national time use surveys since 1992. The results indicate that on average, people in Australia spent about 4% of their day (1.0 h) outdoors and 7% (24 minutes) of their recreation time outdoors (ABS 1994, 1996a, 1998). Thus, the quality of the indoor air environment is very important and is considered briefly here. Pollution from indoor sources is discussed in more detail in the Human Settlements Theme Report.
Brown (1997) and the Environment Protection Authority of Victoria (EPAV 1993) reviewed relationships between indoor and outdoor air quality. Large ranges of indoor to outdoor concentration ratios were reported. Ozone is rapidly scavenged indoors and yields an indoor to outdoor concentration ratio that ranges between 0.1 and 0.7. Carbon monoxide generally has a ratio of 1.0, but this can increase in buildings with gas stoves, unflued heaters or in environments where there is substantial tobacco smoke. Total suspended particulate matter in the absence of indoor activities has ratios that range from 0.1 to 1.0, but the latter figure can increase to 3.5 with substantial indoor activity: again, high ratios are associated with tobacco smoke. Lead ratios are 0.6 to 0.8 in non-air-conditioned houses, which fall to the range 0.3 to 0.5 in air-conditioned buildings.
A Indoor (c i) and outdoor (c a) concentrations of air pollutants.
B Ratio of indoor exposure to outdoor exposure.
Source: Beer and Walsh (1997).
Figure 115 shows simultaneous readings over four days of outdoor and indoor airborne fine particulate matter as measured by light scattering. In general, the indoor air can be modelled by assuming that peaks in the outdoor air will diffuse indoors. This means that the indoor peaks are generally lower, and later, than the outdoor peaks. Nevertheless, as shown during 11 July, there are times when indoor peaks are not related to outdoor events.
Figure 115: Nephelometer readings of outdoor and indoor particles over seven days.
Source: CSIRO Atmospheric Research
For those situations where there are no indoor sources, the ratio between indoor (ci) and outdoor (ca) concentrations of air pollutants can be calculated as well as γ, the ratio of indoor exposure to outdoor exposure that follows from the ratio of concentrations and the typical time spent indoors and outdoors (see table above).
During 1999, the New South Wales Health Department conducted a survey of the sources of indoor cooking and heating using a random telephone survey of 2000 homes throughout the State (see Figure 116). It remains of concern that 20% of the houses in Sydney, and 19% in other areas of the State continue to use unflued gas heaters, because of the possibility of high nitrogen dioxide levels in such houses.
Figure 116: Fuel types for cooking and heating in New South Wales, expressed as percentages.
Source: Public Health Division (2000)
Air quality action plans [A Indicator 3.15]
In addition to the legislative requirements, environmental authorities seek to improve the quality of urban air in several ways. These methods are explained in documents that are generically referred to here as action plans, although they may carry many different names, such as management plans, improvement plans and strategies. Because the Commonwealth, states and territories have traditionally set air management criteria, plans and monitoring (e.g. through the State Environment Agency), local government authorities have had little capacity or responsibility for regulating air quality management.
Commonwealth government National initiatives to minimise air pollution have been discussed in International and national initiatives. This section concentrates on state and local government initiatives.