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- Black, R. R., et al.
(författare)
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Emission factors for PCDD/PCDF and dl-PCB from open burning of biomass
- 2012
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Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 38:1, s. 62-66
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Tidskriftsartikel (refereegranskat)abstract
- The Stockholm Convention on Persistent Organic Pollutants includes in its aims the minimisation of unintentional releases of polychlorinated dibenzo-dioxins and dibenzofurans (PCDD/PCDF) and dioxin like PCB (dl-PCB) to the environment Development and implementation of policies to achieve this aim require accurate national inventories of releases of PCDD/PCDF/dl-PCB. To support this objective, the Conference of Parties established a process to review and update the UNEP Standardized Toolkit for Identification and Quantification of Dioxin and Furan Releases. An assessment of all emission inventories was that for many countries open burning of biomass and waste was identified as the major source of PCDD/PCDF releases. However, the experimental data underpinning the release estimates used were limited in number and, consequently, confidence in the accuracy of the emissions predictions was low. There has been significant progress in measurement technology since the last edition of the Toolkit in 2005. In this paper we reassess published emission factors for release of PCDD/PCDF and dl-PCB to land and air.In total, four types of biomass and 111 emission factors were assessed. It was found that there are no systematic differences in emission factors apparent between biomass types or fire classes. The data set is best described by a lognormal distribution. The geometric mean emission factors (EFs) for releases of PCDD/PCDF to air for the four biomass classes used in the Toolkit (sugarcane, cereal crops, forest and savannah/grass) are 1.6 mu g TEQ(t fuel)(-1), 0.49 mu g TEQ(t fuel)(-1), 1.0 mu g TEQ(t fuel)(-1) and 0.4 mu g TEQ(t fuel)(-1), respectively. Corresponding EFs for release of PCDD/PCDF to land are 3.0 ng TEQ (kg ash)(-1), 1.1 ng TEQ (kg ash)(-1), 1.1 ng TEQ (kg ash)(-1) and 0.67 ng TEQ (kg ash)(-1). There are now also sufficient published data available to evaluate EFs for dl-PCB release to air for sugarcane, forest and grass/savannah; these are 0.03 mu g TEQ (t fuel)(-1), 0.09 mu g TEQ (t fuel)(-1) and 0.01 mu g TEQ (t fuel)(-1), respectively. The average EF for dl-PCB release to land is 0.19 ng TEQ (kg ash)(-1). Application of these EFs to national emissions of PCDD/PCDF for global estimates from open burning will lower previous estimates of PCDD/PCDF releases to air and to land by 85% and 90%, respectively. For some countries, the ranking of their major sources will be changed and open burning of biomass will become less significant than previously concluded.
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| 2. |
- Black, R. R., et al.
(författare)
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Emissions of PCDD and PCDF from combustion of forest fuels and sugarcane : A comparison between field measurements and simulations in a laboratory burn facility
- 2011
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 83:10, s. 1331-1338
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Tidskriftsartikel (refereegranskat)abstract
- Release of PCDD and PCDF from biomass combustion such as forest and agricultural crop fires has been nominated as an important source for these chemicals despite minimal characterisation. Available emission factors that have been experimentally determined in laboratory and field experiments vary by several orders of magnitude from <0.51 mu g TEQ(t fuel consumed)(-1) to >1001 mu g TEQ(t fuel consumed)(-1). The aim of this study was to evaluate the effect of experimental methods on the emission factor.A portable field sampler was used to measure PCDD/PCDF emissions from forest fires and the same fuel when burnt over a brick hearth to eliminate potential soil effects. A laboratory burn facility was used to sample emissions from the same fuels. There was very good agreement in emission factors to air (EF(Air)) for forest fuel (Duke Forest, NC) of 0.52 (range: 0.40-0.79), 0.59 (range: 0.18-1.2) and 0.75 (range: 0.27-1.2) mu g TEQ(WHO2005) (t fuel consumed)(-1) for the in-field, over a brick hearth, and burn facility experiments, respectively. Similarly, experiments with sugarcane showed very good agreement with EFAir of 1.1 (range: 0.40-2.2), 1.5 (range: 0.84-2.2) and 1.7 (range: 0.34-4.4) mu g TEQ (t fuel consumed)(-1) for in-field, over a brick hearth, open field and burn facility experiments respectively. Field sampling and laboratory simulations were in good agreement, and no significant changes in emissions of PCDD/PCDF could be attributed to fuel storage and transport to laboratory test facilities.
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