Air Dispersion Model Report. For. Boylan Group Ltd.

Transcription

1 Appendix E: Air Dispersion Model Air Dispersion Model Report For Ltd. (Document no: ) Environmental Efficiency 97

2 QF 1. v2 Document Lead Sheet Document Title Air Dispersion Model for Project No. 632 Document No Client Address New Found Well, Terminfeckin, Drogheda, Co. Louth Signed for and on behalf of Issue Status Date Author Environmental Client Efficiency 1.01 Approved 06/07/06 RTS Where it is a requirement that this report be issued to a regulatory or other authority, then the client should sign the appropriate place in the above table and, unless specifically agreed in writing to the contrary, forward copies to the appropriate authority (e.g. EPA). EEC Project Manager: EEC Document Author: Tom Griffiths, MSc Conditions relating to the issue of this report: Ronan Sutcliffe, Dip. Environmental Protection 4. No alteration to this report by third parties is permitted 5. Where this report is reproduced, it shall only be reproduced in full. 6. Reports remain the property of Environmental & Efficiency Consultants (Ireland) Limited until paid for in full. Environmental Efficiency 98

3 Contents 1 Introduction Methodology Results Input Data Results Evaluation of Results Conclusion and Recommendations Appendices Appendix 1 Map of Effected Area Appendix 2 Overview of model results Environmental Efficiency 99

4 1 Introduction This report presents an overview of the results of a VOC air model that was run by Environmental Efficiency Consultants for. The purpose of the study is to access any impact that VOC emissions may have on the residence and indeed any receptors in the vicinity of the plant in Drogheda, Co. Louth. 2 Methodology Screen 3, which is a US EPA air dispersion-screening modelling program for single stationary sources, however there is a procedure for merging multiple stacks into a single representative stack, providing that the stacks within 100m of each other, this is described in the USEPA Screening Procedures for Estimating the Air Quality Impact of Stationary Sources (Section 2.2). The two stacks were therefore combined into a single stack using this procedure. Emission values used for the model are a worst case scenario, obtained by taking the result from the stack with the highest concentration and multiplying by the number of stacks. Terrain modelling was not taken into account as the area surrounding the plant is flat. The program was used to estimate the maximum 1 hr average ground level concentration that can potentially be emitted from the two stacks onsite. The model was run using emission values that were obtained from onsite sampling of the air streams from the plant during normal production Due to the shape of the building and adjacent structures building downwash was considered in the calculations, this includes concentration estimates that may occur in cavities. 3 Results 3.1 Input Data Source type Point Emission Rate: 0.16 g/sec Release Height: 6 m Inside Diameter 0.3 m Vol Flow 0.7 m 3 /sec Stack temp K Ambient Temp K Receptor Height 0 m Urban / rural 'Urban Building downwash Yes Min Horiz Bldg dim 90.2 M Max Horiz Bldg dim 95.4 M Meteorological Data Full Use Discrete distance array Yes Environmental Efficiency 100

5 3.2 Results Table 3-1 Screen 3 Model Table of Results Distance (m) Conc. µg/m Distance to max concentration: 20 m Max concentration : µg/m 3 (See Appendix 2 for complete list of results) Environmental Efficiency 101

6 4 Evaluation of Results Below are Occupational exposure limits (OEL) taken for an 8-hour reference period for the most significant solvents used on site. As is usual in air dispersion modelling the maximum resulting ground level concentration is compared with 1/40 th of these OEL s. Results Ground level (50m) : mg/m 3 Site boundary (30m) : mg/m 3 Cavity Calc 1 : < mg/m 3 Cavity Calc 2 : < mg/m 3 OEL s (1/40 th ) By far the most abundant chemical used on this site is, distillates (petroleum) hydrotreated light. There are no OEL s available for this; however it is a mixture of C10-C14 Napthenes for which there are. Napthenes: mg/m 3 There were no limits available for some solvents, all limits were taken from EH40/2002 Occupational Exposure Limits Conclusion and Recommendations The screen model shows peak solvent emissions at ground level and in the cavities are all well below the threshold limits. Environmental Efficiency 102

7 Appendix 6 Map of Effected Area Environmental Efficiency 103

8 Appendix 7 Overview of model results Environmental Efficiency 104

9 Environmental Efficiency 105