Our study is the first to be published in a scientific journal on the levels of outdoor air pollution that can occur near active outdoor smokers. Previously, the exact level of air pollution that could occur outdoors from smoking under various circumstances of proximity and wind was unknown. Our study is also unique in that we have used, tested, and calibrated 5 different kinds of instruments to measure real-time outdoor air pollution levels. These instruments allowed us to characterize peak pollution levels on a second-by-second or minute-by-minute basis.