4613.0 - Australia's Environment: Issues and Trends, Jan 2010
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 28/01/2010
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This document was added or updated on 05/02/2010. PARTICULATE CONCENTRATIONS, DAILY 24-HOUR PM10, SELECTED CITIES Note: “Days of exceedence” refers to the number of days in which average PM10 concentrations exceeded the NEPM standard. Each city contains several PM10 monitoring stations. The data presented are an average of exceedence days across each PM10 monitoring station in each city. Melbourne averages only consider stations with data available for at least 75% of days in a given year. Source: New South Wales Department of Environment, Climate Change and Water; Queensland Department of Environment and Resource Management; Victoria Environment Protection Authority. Airborne particles may be solid matter (such as dust, dirt or soot) or liquid droplets. These particles result from both natural and human sources. Natural sources include bushfires, dust storms, pollens and sea spray. Human activities that create airborne particles include motor vehicle emissions, industrial processes, use of unpaved roads and woodheater use (Endnote 1). Particle pollution reduces visibility on roads, which can cause a safety issue. It has also been linked to respiratory illnesses and cardiovascular disease (Endnote 1). Not all airborne particles are large enough to be seen by the human eye. PM10 and PM2.5 are two examples of particles that can only be detected with a microsope. PM10 particles are those less than 10 micrometres (µm) in diameter. For comparison, the diameter of a human hair is approximately 70 µm (Endnote 1). In June 1998, the National Environment Protection Council created the ambient air quality National Environment Protection Measure (NEPM), which set uniform standards for outdoor air quality. The one-day standard for PM10 is 50 µg/m3 (micrograms per cubic metre) (Endnote 2). In most years since 1998, the average number of PM10 exceedence days in Australia’s three most populated cities has been below 10. However, there was a sharp rise in Sydney’s number of exceedence days in 2002, mainly due to severe forest fires and dust storms in the area (Endnote 2). The National Environment Protection Measure (NEPM) was varied in 2003 to include advisory reporting standards for PM2.5 (particulate matter with a diameter of less than 2.5µm), as well as PM10. The NEPM one-day standard for PM2.5 is 25 µg/m3 (Endnote 3). DAILY PEAK 4-HOUR OZONE, SELECTED CITIES Note: “Days of exceedence” refers to the number of days in which average peak 4-hour ozone concentrations exceeded the NEPM standard. Each city contains several ozone monitoring stations. The data presented are an average of exceedence days across each ozone monitoring station in each city. Melbourne averages only consider stations with data available for at least 75% of days in a given year. Source: New South Wales Department of Environment, Climate Change and Water; Queensland Department of Environment and Resource Management; Victoria Environment Protection Authority. The smog found in Australian cities during the warmer months of the year is caused by photochemical oxidants, such as ozone and other chemicals like formaldehyde (Endnote 4). Ozone and other photochemical oxidants are created when sunlight falls on a combination of chemicals in the air. Cities that receive a lot of sunshine, high temperatures and moderate winds for extended periods of time are likely to experience relatively high concentrations of photochemical oxidants (Endnote 4). The chemicals that react to form ozone are nitrogen oxides and reactive organic substances. These chemicals are produced by motor vehicle exhaust, oil refining, printing, petrochemicals, lawn mowing, aviation, bushfires and burning off. Motor vehicle exhaust fumes produce up to 70% of the nitrogen oxides and up to 50% of the reactive organic substances that form ozone (Endnote 4). Ozone occurs naturally in the lower atmosphere in concentrations of about 0.04 parts per million (ppm) and that amount is not harmful to human health. However, in higher concentrations ozone can irritate the nose, airways and lungs. The National Environment Protection Measure (NEPM) standard for ozone measured over a four hour period is 0.08 ppm. In most Australian towns and cities, the level of ozone in the air does not exceed the NEPM standard (Endnote 4). Even large cities like Melbourne and Brisbane averaged less than two days of exceedence in each year between 1998 and 2008. Of Australia’s three most populous cities, Sydney recorded the most four-hour ozone NEPM exceedences between 1998 and 2008. Sydney’s second-warmest year on record was 2001 (Endnote 5), and this was reflected in its average number of ozone exceedence days that year, which was higher than 20. DAILY PEAK 1-HOUR SULPHUR DIOXIDE, SELECTED REGIONAL CENTRES Note: The National Environment Protection Measure (NEPM) standard maximum concentration for one-hour SO2 is 0.2 parts per million. The graph shows days in which exceedences occurred, not total number of exceedences per year (as there may be more than one exceedence per day). Source: Queensland Department of Environment and Resource Management; South Australia Environment Protection Authority. Sulphur dioxide (SO2) is a colourless, irritating and reactive gas with a strong odour. Emissions of sulphur dioxide are primarily from industrial operations that burn fuels such as coal, oil and gas. It is also emitted by vehicles. It irritates the nose, throat and airways, and people with asthma or similar conditions are at risk of exacerbating these existing health problems (Endnote 6). Ambient (outdoor) sulphur dioxide concentrations are generally low in Australian towns and cities. The highest concentrations are found around petrol refineries, chemical manufacturing industries, mineral ore processing plants and power stations (Endnote 6). In recent years, one-hour SO2 concentrations have been below the National Environment Protection Measure (NEPM) standard levels at Gladstone, the Lower Hunter and La Trobe Valley (power generation areas using coal) (Endnote 7). Sulphur dioxide pollution is still an issue in some mining/minerals processing centres, such as Port Pirie (about 200 km north of Adelaide in South Australia) and Mount Isa (in northwest Queensland). However, other centres, such as Kalgoorlie and Kwinana in Western Australia, have reduced their SO2 levels since the early 1990s and are now meeting the National Environment Protection Measure (NEPM) standard. These changes have been attributed to improved regulation and best practice industry technology (Endnote 8). ENDNOTES 1. Department of the Environment, Water, Heritage and the Arts, 2005, Particles – Air quality fact sheet, <http://www.environment.gov.au/atmosphere/airquality/publications/particles.html>, last viewed November 2009. 2. Environment Protection Heritage Council, Reports from jurisdictions on the implementation of the Ambient Air Quality NEPM 2007–08. 3. Bureau of Meteorology, 2002, Weather diary for year 2002, <http://www.bom.gov.au/announcements/media_releases/nsw/year2002.shtml>, last viewed November 2009. 4. Department of the Environment, Water, Heritage and the Arts, 2005, Ground-level ozone – Air quality fact sheet, <http://www.environment.gov.au/atmosphere/airquality/publications/ozone.html>, last viewed November 2009. 5. Bureau of Meteorology, 2002, Fiery December ends Sydney’s second-warmest year on record, <http://www.bom.gov.au/announcements/media_releases/nsw/20020102.shtml>, last viewed November 2009. 6. Department of the Environment, Water, Heritage and the Arts, 2005, Sulfur dioxide (SO2) – Air quality fact sheet, <http://www.environment.gov.au/atmosphere/airquality/publications/sulfurdioxide.html>, last viewed November 2009. 7. State environmental protection agencies. 8. Western Australia Environmental Protection Authority, State of the Environment Report 2007: Atmosphere – Sulfur dioxide, <http://www.soe.wa.gov.au/report/atmosphere/sulfur-dioxide.html>, last viewed November 2009.
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