title: Contribution of fine particulate matter sources to indoor exposure in bars, restaurants, and cafes.
abstract: This study investigated the contribution of sources and establishment characteristics, on the exposure to fine particulate matter (PM(2.5)) in the non-smoking sections of bars, cafes, and restaurants in central Zurich. PM(2.5)-exposure was determined with a nephelometer. A random sample of hospitality establishments was investigated on all weekdays, from morning until midnight. Each visit lasted 30 min. Numbers of smokers and other sources, such as candles and cooking processes, were recorded, as were seats, open windows, and open doors. Ambient air pollution data were obtained from public authorities. Data were analysed using robust MM regression. Over 14 warm, sunny days, 102 establishments were measured. Average establishment PM(2.5) concentrations were 64.7 microg/m(3) (s.d. = 73.2 microg/m(3), 30-min maximum 452.2 microg/m(3)). PM(2.5) was significantly associated with the number of smokers, percentage of seats occupied by smokers, and outdoor PM. Each smoker increased PM(2.5) on average by 15 microg/m(3). No associations were found with other sources, open doors or open windows. Bars had more smoking guests and showed significantly higher concentrations than restaurants and cafes. Smokers were the most important PM(2.5)-source in hospitality establishments, while outdoor PM defined the baseline. Concentrations are expected to be even higher during colder, unpleasant times of the year.
  
  
  CONCLUSIONS
  Smokers and ambient air pollution are the most important sources of fine airborne particulate matter (PM(2.5)) in the non-smoking sections of bars, restaurants, and cafes. Other sources do not significantly contribute to PM(2.5)-levels, while opening doors and windows is not an efficient means of removing pollutants. First, this demonstrates the impact that even a few smokers can have in affecting particle levels. Second, it implies that creating non-smoking sections, and using natural ventilation, is not sufficient to bring PM(2.5) to levels that imply no harm for employees and non-smoking clients.
authors.affiliation: Institute for Work and Health [Institut universitaire romand de Santé au Travail], University of Lausanne and University of Geneva, Lausanne, Switzerland.
authors.forename: B-J
authors.initials: BJ
authors.lastname: Daly
authors.forename: K
authors.initials: K
authors.lastname: Schmid
authors.forename: M
authors.initials: M
authors.lastname: Riediker
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D004784:Environmental Monitoring; D006801:Humans; D006813:Humidity; D009391:Nephelometry and Turbidimetry; D052638:Particulate Matter / Q000032:analysis*; D011633:Public Facilities / Q000145:classification / Q000592:standards; D012147:Restaurants / Q000145:classification / Q000295:instrumentation / Q000592:standards; D012621:Seasons; D013696:Temperature; D013997:Time Factors; D014028:Tobacco Smoke Pollution / Q000032:analysis; D014691:Ventilation
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D014028:Tobacco Smoke Pollution