Exposure to fine and ultrafine particles from secondhand smoke in public places before and after the smoking ban, Italy 2005

Background: A smoking ban in all indoor public places was enforced in Italy on 10 January 2005. Methods: We compared indoor air quality before and after the smoking ban by monitoring the indoor concentrations of fine (<2.5 mu m diameter, PM2.5) and ultrafine particulate matter (<0.1 mu m diameter, UFP). PM2.5 and ultrafine particles were measured in 40 public places ( 14 bars, six fast food restaurants, eight restaurants, six game rooms, six pubs) in Rome, before and after the introduction of the law banning smoking ( after 3 and 12 months). Measurements were taken using real time particle monitors (DustTRAK Mod. 8520 TSI; Ultra-fine Particles Counter-TRAK Model 8525 TSI). The PM2.5 data were scaled using a correction equation derived from a comparison with the reference method (gravimetric measurement). The study was completed by measuring urinary cotinine, and pre-law and post-law enforcement among non-smoking employees at these establishments Results: In the post-law period, PM2.5 decreased significantly from a mean concentration of 119.3 mu g/m(3) to 38.2 mu g/m(3) after 3 months (p<0.005), and then to 43.3 mu g/m(3) a year later (p<0.01). The UFP concentrations also decreased significantly from 76 956 particles/cm(3) to 38 079 particles/cm(3) (p<0.0001) and then to 51 692 particles/cm(3) (p<0.01). Similarly, the concentration of urinary cotinine among non-smoking workers decreased from 17.8 ng/ml to 5.5 ng/ml (p<0.0001) and then to 3.7 ng/ml (p<0.0001). Conclusion: The application of the smoking ban led to a considerable reduction in the exposure to indoor fine and ultrafine particles in hospitality venues, confirmed by a contemporaneous reduction of urinary cotinine.