In order to reduce human and pig exposure to aerosols in pig housing units three techniques have been developed and tested. The techniques are: Filtration and recirculation of air in weaner rooms, weekly vacuum cleaning in a finishing house and weekly washing with water of weaned piglets. All the experiments were carried out on 70-92 pigs. The air filtration study was replicated seven times, the vacuum study was replicated two times and the washing study was replicated six times. In the air filtration study gravimetrical dried aerosol concentrations was reduced 40%. Although this did not result in significant changes to feed intake or daily gain for the pigs during the weaning stage. The vacuum study was able to improve reduction of aerosol particles by 10% after four days. Although no impact was made on feed intake or daily gain. But, pigs in a room that was not vacuumed had more veterinary treatments for respiratory health disorders. For the washing study aerosol particles were reduced 10%, and on the day of washing it was reduced 25%. Again there were no significant improvements to pig performance. The researchers conclude by saying that the costs of implementing these aerosol concentration reduction techniques do not compensate for the  pig performance improvements that they yield.