Sensitivity of predicted bioaerosol exposure from open windrow composting facilities to ADMS dispersion model parameters

P Douglas,S.F Tyrrel,R.P Kinnersley,M Whelan,P.J Longhurst,K Walsh,S.J.T Pollard,G.H Drew

doi:10.1016/j.jenvman.2016.10.003

P Douglas, S.F Tyrrel + Show 6 more

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https://doi.org/10.1016/j.jenvman.2016.10.003

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Abstract

Bioaerosols are released in elevated quantities from composting facilities and are associated with negative health effects, although dose-response relationships are not well understood, and require improved exposure classification. Dispersion modelling has great potential to improve exposure classification, but has not yet been extensively used or validated in this context. We present a sensitivity analysis of the ADMS dispersion model specific to input parameter ranges relevant to bioaerosol emissions from open windrow composting. This analysis provides an aid for model calibration by prioritising parameter adjustment and targeting independent parameter estimation. Results showed that predicted exposure was most sensitive to the wet and dry deposition modules and the majority of parameters relating to emission source characteristics, including pollutant emission velocity, source geometry and source height. This research improves understanding of the accuracy of model input data required to provide more reliable exposure predictions.

Highlights

Composting of organic waste is a common practice in many parts of the world and generates a useful product from waste which might otherwise go to landfill
The largest and most consistent of these changes are observed with (i) GEO, with a line source, where the ranking tends to decrease with the Wet Deposition Module (WDM) included; (ii) surface roughness (SRO) where the ranking decreases by 10, except with a line source where it decreases by 3; (iii) latitude (LAT) where inclusion of the WDM causes a decrease in ranking by 6 for point and area sources and 13 for a line source; and (iv) pollutant specific heat capacity (SHC) where inclusion of the WDM causes a decrease in ranking by 10 for point and area sources and 4 for a line source
The results presented provide a focus for further research into the quantification of dispersion model input parameters with respect to bioaerosol emissions from an open windrow composting environment

Summary

Introduction

Composting of organic waste is a common practice in many parts of the world and generates a useful product from waste which might otherwise go to landfill. An understanding of the magnitude and frequency of bioaerosol emissions and resulting temporal and spatial patterns of exposure is required in order to assess the potential health risks. This is difficult as the nature, scale and frequency of composting processes and, emissions at open windrow sites (which represent the greatest proportion of facilities in the UK) are complex and not well understood (see Supplementary Materials [SM] 1) and vary by individual site. Sampling data from composting facilities with high spatial and temporal resolution are, rare

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