06 Jun ASHRAE Position Document on infectious Aerosols
ABSTRACTThe pathogens that cause infectious diseases are spread from a primary host to secondaryhosts via several different routes. Some diseases are known to spread by infectious aerosols;for other diseases, the route of transmission is uncertain. The risk of pathogen spread, andtherefore the number of people exposed, can be affected both positively and negatively by theairflow patterns in a space and by heating, ventilating, and air-conditioning (HVAC) and localexhaust ventilation (LEV) systems. ASHRAE is the global leader and foremost source of tech-nical and educational information on the design, installation, operation, and maintenance ofthese systems. Although the principles discussed in this position document apply primarily tobuildings, they may also be applicable to other occupancies, such as planes, trains, and auto-mobiles.ASHRAE will continue to support research that advances the knowledge base of indoor air-management strategies aimed to reduce occupant exposure to infectious aerosols. Chiefamong these ventilation-related strategies are dilution, airflow patterns, pressurization,temperature and humidity distribution and control, filtration, and other strategies such as ultra-violet germicidal irradiation (UVGI). While the exact level of ventilation effectiveness varies withlocal conditions and the pathogens involved, ASHRAE believes that these techniques, whenproperly applied, can reduce the risk of transmission of infectious diseases through aerosols.