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Environmental Exposure
In this section, the predicted environmental concentration (PEC) of formaldehyde is calculated for various environmental compartments using modelling techniques. The modelling results are presented as annual averages and maximum 24-hour averages. Annual averages are relevant for long-term (chronic) exposure, whereas 24-hour averages are more representative of acute exposure. An averaging time of 24 hours is also specified for formaldehyde in the Air Toxics National Environmental Protection Measure (NEPC, 2004) with the monitoring investigation level set at 40 ppb (see Section 18.1.1 for details). First, a PEC value for each of the point and diffuse sources of release is calculated, and then these values are combined to determine a final PEC. Where available, published monitoring studies are also summarised and used to verify the PEC values. The formaldehyde release estimates are primarily from the NPI emission database (NPI database at www.npi.ea.gov.au). Most of the NPI emissions data are themselves estimations, determined by a range of techniques, including mass balance calculations, use of emissions factors, and sampling and direct measurement. As such, the PEC predictions should be interpreted cautiously owing to uncertainties in the initial release estimates. A number of different approaches have been adopted to calculate PECs, depending on the type of source. The modelling was carried out by Commonwealth Scientific and Industrial Research Organisation (CSIRO) Atmospheric Research Division and details of the modelling techniques and results are provided in Appendix 6.
Emissions of formaldehyde resulting from industrial activities are difficult to assess owing to the high diversity in use patterns and the high number of both small and large companies using formaldehyde or manufacturing products containing formaldehyde. While the NPI estimates are a reasonably good indicator of the major contributors, the data are incomplete. Data from the Australian Bureau of Statistic (ABS) suggest that from 5000 to 10 000 companies should be reporting emissions (although not all of these companies necessarily emit formaldehyde), but only about 3000 facilities reported emissions in the 2001–2002 reporting year and 3400 for the 2002-2003 reporting year. Figure 13.1 provides a breakdown by industry category of point source emissions from the 34 industries and 196 facilities reporting formaldehyde emissions to the NPI in the financial year 2001-2002 and 38 industries and 257 facilities for the 2002-2003 financial year. These emissions are combined and appear as industry emissions in Figure 8-1. Some of the original NPI industry categories have been changed or combined for this report. The major industrial contributors of atmospheric point source emissions of formaldehyde are the mining, wood and paper industries, and electricity supply. In the following summaries of point source data, the average emissions are used to represent emissions and potential exposure concentrations owing to the wide variability in releases from each industrial facility including some facilities reporting no emissions. The minimum and maximum emissions are also reported. The detailed emission data for a number of major industries are tabulated in Appendix 7. The details of modelling for PEC values, such as source configuration and modelling techniques are presented in Appendix 6, Section A2. Only results are reported here. The release estimates used in the modelling are primarily from emissions data listed in the NPI database for the 2001-2002 reporting year. The 2002-2003 NPI data reported in this section became available after the modelling was conducted, therefore, were not used in the PEC estimations. However, it is expected to be directly proportional to those estimated for 2001-2002. All PEC values are calculated using the conversion factor 1 ppb = 1.20 µg/m3, which is appropriate for ambient conditions of 25 ºC. Figure 13.1: Formaldehyde emissions (NPI database) for each industry category for (a) 2001-2002 and (b) 2002-2003. The figure in brackets indicates the number of facilities reporting in each category 
The average and maximum formaldehyde emission rates derived from the NPI database from the various types of mining operations are given in Table A7-1 in Appendix 7.
1.8 ppb and the maximum 24-hour average was 8.1 ppb based on the average source emissions for the 2001-2002 reporting year. These results are approximately inversely proportional to the diameter of the area source (for a given emission rate). (see Appendix 6, A2.1 for details) Given that the main sources of emissions from mining operations are distributed surface sources, the area of emissions is likely to be approximately proportional to the emissions rate, so that PECs from the largest emitter are expected to be similar to those from the average emitter. Directory: data -> assets -> word doc -> 0006 word doc -> Commonwealth of Australia 2002 word doc -> Commonwealth of Australia 2000 word doc -> Priority Existing Chemical word doc -> Rail safety news issue 6 – October 2011 word doc -> Review of Multiple Chemical Sensitivity: Identifying 0006 -> Board Endorsed October 2009 amended 13-09-11 with extra units 0006 -> Rt Hon Andrew Lansley cbe mp secretary of State for Health 0006 -> Environmental Approvals Application Form Use this form Download 5.77 Mb. Share with your friends:
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