The interest in aerosol contamination of aircraft passenger cabins has increased since the onset of the COVID-19 pandemic. Mathematical models have been developed to help describe how an aerosol behaves in a closed space. The number of infectious particles inhaled is of scientific interest because it can be related to the risk of getting ill from a pathogen. The data required to calculate these results is often difficult to obtain in real world settings. In fact, particle inhalation details are not obtained in the day-to-day routine of a health care environment and are they not required to maintain safety. Hospital isolation rooms provide safe air quality without measuring the aerosol contaminant concentration of the source or a person’s volume flow rate of breathing. Using the concept of the aerosol concentration ratio and applying hospital isolation room standards, a method to set safe aircraft passenger cabin air quality standards is discussed.