Defra - Department for Environment, Food and Rural Affairs.

Science Search

Science and Research Projects

Return to Science Search homepage   Return to Project List

Emissions and abatement of dust from poultry houses - AC0104

Current European health standards for particles are based on the mass concentration of particulate matter contained within particles with an aerodynamic diameter of 10 ƒÝm or less (PM10). These small particles penetrate deeply into the lung and are therefore of particular concern to the health of the human population. A previous study (Wathes et al, 2002) has shown that annual agricultural emissions of PM10 amount to about 8% of the total emission of urban sources. The largest contribution to agricultural emissions was attributed to poultry production (40% of the total).

In addition to contributing to PM10 concentrations, a substantial proportion of agricultural particulates comprise bioaerosols, i.e. particles of biological origin and/or activity, due to the nature of the major sources (livestock production). Bioaerosols may pose an additional hazard over and above PM10 from non-agricultural sources because of their biological nature, e.g. aeroallergens and zoonoses. The potential health hazards of agricultural bioaerosols to the rural population are largely linked to the characteristics i.e. the physical, chemical and microbiological properties of particularly the smaller fraction of dust emitted from the source.

To date no definite conclusions can be drawn about the potential health hazards of agricultural, especially poultry, dust to the rural population as very little information is available on the properties of poultry dust aerosols in general and bio-aerosols in particular, including the viability/infectivity of airborne micro-organisms (see review by Wathes, 1998). In general, the lifetime of viable organisms from poultry under ambient conditions is thought to be low, but measurements are lacking to corroborate this view. The likely exposure level to poultry aerosols in the rural population is also largely unknown. Once the source strengths are estimated then transport and dispersion of particulates of certain sizes can be modelled and thus the theoretical exposure computed. This will allow the nature and extent of the hazard to be estimated and placed in context with other PM10 emissions.

The project aims to provide the required information to enable a full assessment of the human health implications of poultry dust to be made and will identify potential abatement techniques to reduce the exposure levels. Poultry dust will be characterised in terms of its chemical, physical and microbiological composition. Samples will be taken from the three most prevalent production systems, i.e. broilers on litter, laying hens in cages and laying hens in aviary type systems. The samples will be taken at the point of emission during winter and summer conditions when the emission is expected to be at its lowest and highest, respectively. In the case of broiler production the samples will be taken during week 5 or 6 of the growing cycle. The samples will be analysed in situ for particle mass, particle size distribution and fine particle composition and off line for full chemical and microbiological composition. In addition samples will be taken at a range of distances down wind from the source and analysed for microbiological composition. From the results of this study and a thorough literature review, the potential health implications of poultry dust can be assessed.

As part of the IPPC (Integrated Pollution Prevention and Control) implementation, the industry is required to control emission of ammonia and dust using the best available techniques (BAT). New techniques are emerging to reduce dust concentrations inside poultry houses, benefiting stockmen and birds alike, and hence reducing dust emissions. Following a review of literature and a survey of the industry, relevant dust abatement techniques will be assessed for their potential. It is important to separate the overall efficacy of the abatement techniques in terms of PM10 and the reduction of specific bio-aerosols. Therefore, samples will be taken from one or two broiler buildings with the most promising abatement technique(s) in use and compared against the traditional approach. The samples will be analysed using a reduced set of the techniques used previously to identify the chemical, physical and microbiological properties. The emphasis of the assessment will not only be on the efficacy of the abatement technique, but also on costs and practicality (BAT). The impact on other forms of pollution, for instance gaseous ammonia emissions, will also be assessed.

Currently no guidelines exist for the estimation of emission factors, allthough an European guidebook on PM emissions from animal husbandry is in preparation. The current emission factors are based on a very small database (Klimont et al, 2002). To enable the compilation of the annual dust emission inventory, improved emission factors for PM10 will be established for the three most prevalent production systems given above (by analogy with the ammonia emission factors, Misselbrook et al, 2000).

Although making a moderate contribution (8%) to the national UK primary dust (PM10) inventory overall, there is growing concern that dust from livestock buildings can cause exceedances of UK Air Quality Standards locally. In addition, the presence of bioaerosols in dust from livestock buildings poses a significant but to date largely unknown and unquantified risk to the human population in the vicinity (Wathes et al, 2002). The main aim of this project is to characterise poultry dust (40% of agricultural dust emissions) in terms of its physical, chemical and microbiological properties through detailed measurements on a limited number of locations. The identified properties will enable assessment of the human health implications of dust emissions, once the exposure levels have been determined.
Abatement of dust emission is the obvious route to lower the human exposure levels. Potential abatement techniques will be assessed on the basis of efficacy, practicality, and cost. One or two abatement method(s) will be tested to identify further the level of dust reduction at source and the properties of the remaining fraction.
Currently no European guidelines currently exist for the estimation of emission factors. A first chapter on PM emissions from animal husbandry is in preparation for the EMEP/CORINAIR Emission Inventory Guidebook (Sully and Hill, 2004), which will include some initial emission factors of PM10 emissions from poultry, based on the methodology proposed by Klimont et al. (2002), based on a very small database. This chapter proposes emission factors of 0.017, 0.27 and 0.35 kg PM10 animal-1 a-1 for laying hens in cages, perchery and broilers on solid ground, respectively (Ulrich Dämmgen, personal communication). By contrast, the NAEI currently uses a much lower emission factor of 0.0588 kg PM10 animal-1 a-1 for broilers, demonstrating the uncertainty in current estimates (e.g. AQEG, 2004).To enable the compilation of the dust emission inventory for the UK, updated dust emission factors will be established by analogy with the ammonia emission inventory. In short, the objectives of this study are:

1) To further characterise the elements of fine dust (PM10) emitted from poultry houses on the basis of its physical, chemical and microbiological properties
2) To assess the human health implications of dust emissions from poultry houses, particularly for those living in the vicinity of poultry production facilities
3) To identify dust emission abatement measures and assess their efficacy and cost
4) To assess the impact of effective dust abatement measures on other forms of pollution
5) To establish dust emission factors for poultry houses under traditional operation and with abatement measures
Project Documents
• Final Report : Characterising poultry dust properties, assessing the human health implications, quantifying emission levels and assessing the potential for abatement   (4344k)
• Final Report - Annex : Appendix A Appendix A Assessment of Poultry Farms in Defra Project CTE0408   (3194k)
Time-Scale and Cost
From: 2006

To: 2009

Cost: £461,188
Contractor / Funded Organisations
Health & Safety Laboratory, Centre for Ecology and Hydrology, ADAS UK Ltd., Royal Veterinary College
Environment and Health              
Environmental Impact              
Livestock Farming              
Sustainable Production              
Fields of Study
Agriculture and Climate Change