In some outbreaks, such as the largest nosocomial SARS outbreak in Hong Kong , fluid dynamics analyses demonstrated a decrease in the predicted average aerosol concentration as the distance from the index patient increased. However, in some other outbreaks, such as the first nosocomial MERS outbreak in South Korea , fluid dynamics analyses predicted a higher average aerosol concentration in distant wards (i.e., downstream wards) than in adjacent wards. Since the distributions of infections transmitted via airborne routes are mainly decided by the dispersion of airborne aerosols , it do not necessarily present an inverse relationship with the distance from the source. Thus, to determine the infection patterns attributable to the airborne route, airflow-dynamic studies that model virus-laden aerosols generated by an index patient should be performed where possible .