“We know that vaccinating can decrease the amount of viruses in the air, so vaccination is a good mechanism to prevent airborne transmission” Swine veterinary consultant Dr. Carmen Alonso in Spain picks out lessons from her detailed studies of air samples inside and outside farms suffering an outbreak of PRRS, influenza A or porcine epidemic diarrhoea --- as well as poultry sites with highly pathogenic avian influenza. Particle size in the air influenced the distance of transmission and also the amount of virus distributed. While larger particles travelled less far than small ones initially, they could be transported a longer total distance after settling on a vehicle that had been parked near the swine barn. Running time: 30 minutes