An electrostatic air filtration system was installed to treat incoming air at a commercial laying-hen house and evaluated in the field. Reduction of incoming particulate matter reached up to 75 percent, varying by season. It is the closest thing available to a commercial poultry inlet filtration trial: not a chamber, not a specific-pathogen-free facility, not a model, but an operating layer house doing its normal work.
The seasonal qualifier is the whole story. Ventilation rate in poultry housing swings enormously across the year, from minimum winter exchange to full tunnel airflow in summer heat, and a filtration system that performs at one end of that range is not the same system at the other. A single headline efficiency figure hides the range that a design actually has to accommodate. This is the poultry version of the problem the swine literature describes as filter loading against a fan curve, except the airflow swing is larger.
Read it alongside the companion modelling work from the same group, which took this 75 percent figure as its input and concluded that at least 90 percent would be needed to reduce avian influenza airborne risk to low or extremely low. Measured field performance and modelled requirement do not currently meet. Note also that the media is electrostatic rather than mechanical, which brings in the charge-decay literature: electret filters have been documented losing efficiency in service with no change in pressure drop to signal it. Stable performance across a service interval should be demonstrated rather than assumed.