Smoking outdoors at pubs and bars: is it a problem? An air quality study

(i) To measure air quality in semi-enclosed outdoor smoking areas of pubs and bars in New Zealand. (ii) To evaluate evidence of drift of fine particulates of secondhand smoke (SHS) from semi-enclosed outdoor smoking areas to indoor (smoke-free) areas. (iii) To evaluate evidence that the degree of communication between the outdoor smoking area and indoor areas influences the level of particulates indoors.

We measured fine particulate levels (PM(2.5)) using portable real-time aerosol monitors in a convenience sample of seven pubs and bars in central Wellington City. This was on one to three occasions (12 measurements in total) over four different nights.

On the first two nights, when there was no or infrequent communication between the outdoor and indoor areas, the mean level of PM(2.5) varied from 32 to 109 μg/m³ in the outdoor smoking area, and from 14 to 79 μg/m³ in the adjacent indoor areas. On nights three and four, communicating doors were generally open most of the time. The mean level of PM(2.5) varied from 29 to 192 μg/m³ in the smoking areas, from 36 to 117 μg/m³ in adjacent indoor areas, and from 23 to 104 μg/m³ in more distant indoor areas. Levels of PM(2.5) in adjacent indoor areas were highest in pubs where communicating doors were open all the time (mean 117 μg/m³), intermediate where communicating doors were open intermittently (mean 85 μg/m³), and lowest when they were wholly or mainly closed (mean 25 μg/m³).

Air quality in semi-enclosed outdoor smoking areas was variable, and in some pubs was very poor. Where free communication exists between outdoor smoking areas and indoor areas, SHS drift can often greatly reduce indoor air quality throughout the pub or bar. Regulations to restrict the degree of communication and proximity of smoking areas to indoor areas may be justified to maintain indoor air quality and to protect health, particularly that of workers.