Twenty-four healthy students walked at least 4 times for one hour under each of the 4 settings: By a busy road, by a busy road wearing ear plugs, in a park, in a park but exposed to traffic noise (65 dB) through speakers. Particles (PM2.5, particle number) and noise levels were measured throughout each walk. Lung function and exhaled NO were measured before, immediately, one hour, and approximately 24 hours after each walk. Blood pressure and heart rate variability were measured every 15 minutes during each walk. Air pollution levels reduced lung function levels. Noise levels reduced systolic blood pressure and heart-rate variability.