Hundreds of millions of passengers travel on U.S. airliners annually,
These large numbers, together with the close proximity required onboar
d, mise a concern about microbiologic disease transmission in cabin ai
r, Previous air quality surveys generally concentrated on environmenta
l tobacco smoke and particulate matter, They largely ignored the micro
organisms also present, We sampled the microbiologic climate of 45 dom
estic and international flights, We also sampled common locations in c
t major southwestern city, The concentration of microorganisms in airl
ine cabin air is much lower than in ordinary city locations, We conclu
de that the small number of microorganisms found in U.S. airliner cabi
n environments does nor contribute to the risk of disease transmission
among passengers.