Characterisation of key factors for dust generation in broiler houses

Particulate matter within broiler houses deteriorates indoor air quality and causes various health problems in both farmers and broilers. To introduce a proper dust control strategy, the dust concentration and the mechanisms of dust generation according to a complicated combination of environmental variables should be understood. In this work, long-term dust monitoring in mechanically and naturally ventilated broiler houses was carried out to determine the key factors affecting dust generation. The micro-climatic factors, such as air temperature and humidity, outdoor weather conditions, age of broilers, activity of broilers, water contents of bedding materials, and ventilation rate, were simultaneously measured to conduct statistical analyses. The ventilation rate of each broiler house was numerically computed using a computational fluid dynamics model. From the observations, relatively high dust concentrations were obviously measured when broiler farmers entered the facility; this was due to the increase in the broiler activity, especially in the autumn and winter seasons when a minimum ventilation rate was generally adopted. Those dust concentration values easily exceeded the occupational exposure limits per their size fractions. Based on statistical analysis, the activity of broilers was found to be a key factor for dust generation in both experimental broiler houses; however, controlling the humidity level may be a practical method to control the generation of the larger fractions, such as inhalable dust, when considering the field-applicability of each variable.