Air pollution in farm buildings and methods of control: a review.

Attention to the degree of gaseous and dust pollution in the atmosphere of poultry houses and buildings housing livestock in general is an essential adjunct to other measures aimed at improving the performance and limitation of losses from disease. The atmosphere should be monitored at regular intervals to ensure that measures taken to prevent the accumulation of toxic gases are adequate. The main hazard of dust pollution is its role in the transmission of infectious disease, and it should be ensured that the level of pollution is kept to a minimum in the immediate surroundings of the stock as distinct from that of the total air space of the building. Whereas ventilation provides a satisfactory means of reducing gaseous pollution, problems arise in its use for the control of dust pollution mainly because of the difficulty of providing a ventilation system which avoids air turbulence. This can result in undesirable effects such as overall or localised chilling within the building and the resuspension of dust deposits. There is also the problem of the intake through ventilators of contaminated dust from the external environment. Care must therefore be taken in the design of houses and ventilation systems to avoid these adverse effects, and intensified study is urgently required to improve ventilation systems currently used in commercial farming practice.