the ability of disposable half-face masks containing activated carbon to protect against inhaled ozone ( o2 ) ( nominal experimental exposure concentration , 0.5 ppm ) was tested using a specially designed mechanical device simulating the breathing of a moderately exercising human , and then tested further by 18 volunteers exposed to o2 in a controlled-environment chamber for 2 h with intermittent mild exercise .
C0004048
inhaled
C0035203
breathing