2.4 Comparison with international benchmarks
There are no Australian goals or standards for ambient concentrations of dioxins against which to assess the NSW results. Similarly, there are not many overseas benchmarks known to the EPA. Those goals that are available tend to use a range of different averaging periods and compounds.
Japan has an annual average goal for I-TEQ of 600 fg/m3 (including coplanar polychlorinated biphenyls) (Ministry of the Environment, Government of Japan 1999, www.env.go.jp/en/lar/regulation/aq.html). Ambient air concentrations of dioxins at all measured sites in NSW were well below this goal. The highest mean annual concentration measured in this study (I-TEQ of 14 fg/m3 at Westmead) is only 2.5% of this yardstick.
Ontario, Canada has an ambient (maximum) criterion for dioxins of 5000 I-TEQ fg/m3 over 24 hours (Ontario Ministry of the Environment 1999, Summary of Point of Impingement Standards, Point of Impingement Guidelines and Ambient Air Quality Criteria, www.ene.gov.on.ca/envision/gp/2424e.pdf). Samples in NSW were collected over 12 or 24 days and, while indicative, are not directly comparable with this goal. However, all measured concentrations in NSW were well below these levels. The maximum result measured (an I-TEQ level of 53 fg/m3 at Westmead over a 12-day sampling period) was just 1% of the Canadian goal.
Page last updated: 26 February 2011
