Smoking in car: monitoring pollution of particulate matter, of organic volatile compounds and of carbon monoxide. The effect of opening the driver's window

Objective: to identify the most suitable marker for monitoring ETS inside a moving car, and to verify the efficacy of window opening to reduce ETS pollution inside the car. Design: experimental pilot study. Setting and participants: monitoring of ETS markers in a moving car. Main outcome measures: we used real time analyzers to measure: square particulate matter as mass (mu g/m(3), PM1, PM2.5, PM10); square suspended particle number (total number of particles sized >0.3 e >0.4 mu m; square the number of particles with aerodynamic size between 0.3-0.4 mu m in diameter; square total volatile organic compounds (TVOC); square carbon monoxide (CO). The recordings were carried out inside a car moving on the road at the speed of 50 km/h, with controlled conditions of temperature and relative humidity. Results: after lighting a cigarette, with driver's window closed, the levels of all the pollutants increased dramatically, with peaks of 700 mu g/m(3) for PM2.5 and PM 10, and of over 600,000 particles/liter, while TVOC reached values up to 6,000 mu g/m(3) and CO up to 6 ppm. When a cigarette was lit with the window 1/4 open, excess pollution was promptly recorded, although with less intensity. With the window completely open, PM, TVOC and CO concentrations were hardly measurable as compared to background levels. On the contrary, particle number increased dramatically up to over 300,000/liter, mostly due to the submicrometric particle fraction in the range 0.3-0.4 mu m. Conclusion: smoking just a cigarette inside a car represents an extremely high exposure to ETS. Partially opening the window is useless to prevent the accumulation of pollutants. Complete window opening is helpful to remove coarse PM and volatile pollutants, but is ineffective against submicrometer particles. Measuring particle number seems to be the best way to assess ETS pollution inside a car. (Epidemiol Prey 2010; 34(1-2): 35-42)