Application of passive diffusion tubes to short-term indoor and personal exposure measurement of nitrogen dioxide

Palmes-type passive diffusion tubes were shown to be as accurate in the measurement of indoor NO2 during short-term (2- and 3-d) exposures as during 1-week exposures. The statistical limit of detection for cumulative NO2 in 2- and 3-d exposure was 150 (nL L−1h). The mean coefficient of variation for duplicate 2- and 3-d exposures was < 13%. A pilot study measuring personal, indoor (living room) and outdoor (just outside the home) NO2 over 3 d for 8 volunteers demonstrated the feasibility and reliability of using passive diffusion tubes for short-term personal exposure measurements, and confirmed the necessity of obtaining actual exposure profiles for a specific subpopulation.