Formation of artefacts while sampling emissions of PCDD/PCDF from open burning of biomass
- 作者：R.R. Blacka ; r.black1@uq.edu.au ; C.P. (Mick) Meyerb ; A. Yatesc ; L. Van Zweitend ; J.F. Muellera
- 关键词：Polychlorinated dibenzo-p-dioxins ; Polychlorinated dibenzofurans ; Persistent organic pollutants ; Bushfires ; Forest fires ; Biomass burning
- 刊名：Chemosphere
- 出版年：2012
- 期刊代码：15_00456535
- 类别：env
- 出版时间：July, 2012
- 卷：88
- 期：3
- 页码：352-357
- 文件大小：296 K
摘要
Emission factors for PCDD/PCDF determined from open combustion are used to estimate national emission budgets; therefore, it is important to have confidence in their accuracy. It has been suspected that artefacts may form due to the presence of hot metal surfaces of sampling equipment, thus skewing emission factors. In this study, emissions of PCDD/PCDF from open burning of forest biomass over a brick hearth were sampled. Five experiments were carried out using a portable sampler. Experiments were designed where the key variable, sample hood and inlet temperatures were manipulated. Other variables such as fuel origin, type and density were consistent. The measured concentration of PCDD/PCDF in the smoke samples ranged from 0.01 渭g TEQ (t fuel)鈭? at the lowest maximum hood temperature (185 掳C) to 15 渭g TEQ (t fuel)鈭? at the highest maximum hood temperature (598 掳C). when hood inlet temperatures exceeded 400 掳C emission factors were significantly elevated and this is attributed to the formation of artefacts that can cause the over estimation of emission factors. The increase in hood temperature also resulted in a change in the PCDD/PCDF congener and homologue profile of the emissions. For example at the lowest temperature (Fire 1) the PCDD/PCDF ratio measured was 50:1, whereas at the highest temperature (Fire 5) this ratio was about 0.53:1. When the sampler hood and inlet temperatures were kept in the normal operating range of <200 掳C, emission factors were comparable to those observed in many previous studies in Australia with emissions dominated by PCDD.