1) The document discusses the transmission of H1N1 influenza A virus indoors and the role of HVAC systems. It describes how low indoor humidity in winter increases the level of infectious airborne droplet nuclei which can spread via HVAC systems. 2) Various methods for capturing and deactivating airborne viruses are discussed, including MERV filters, UV lights, photocatalytic oxidation, and bi-polar ionization, and their effectiveness when used individually or in combination. 3) Preventive measures for healthcare workers are outlined, such as patient isolation, protective equipment, hand hygiene, and environmental cleaning.