The Impact of Ontario Smoke-Free Legislation on Secondhand Smoke in Enclosed Public Places

Abstract

Many studies have evaluated the impact of indoor smoking bans on secondhand smoke (SHS) exposure. No studies have assessed the impact of a smoking ban on SHS in enclosed areas outside separately ventilated, designated smoking rooms (DSRs). This study evaluated the overall impact of the Smoke-Free Ontario Act implemented May 31, 2006, on SHS in bars and coffee shops and the impact of banning DSRs on SHS outside DSRs. Air particulate matter (PM) and carcinogenic particulate polycyclic aromatic hydrocarbons (PPAH) were measured in May 2006 before the ban inside and outside DSRs in Toronto venues (13 coffee shops and 14 bars) that allowed smoking only in DSRs, and in Windsor venues (10 coffee shops and 10 bars) where smoking was allowed in shared spaces. Measurements were repeated 2 months post-ban. Air quality index values (AQIs) were calculated. Mixed model analysis was applied, taking into account measurement errors for repeated measures. Post ban, mean PM and PPAH levels were reduced by 87% (from 494 to 67 mm²/m³) and 94% (from 196 to 11 ng/m³), respectively, inside Toronto DSRs. Mean PM and PPAH levels were reduced by 10% (from 124 to 111 mm²/m³) and 46% (from 45 to 24 ng/m³), respectively, outside Toronto DSRs. In all Windsor venues, mean PM and PPAH levels were reduced by 83% (from 488 to 81 mm²/m³) and 90% (from 107 to 10 ng/m³), respectively. All reductions were statistically significant (p < 0.0001). In Toronto venues, the AQI was reduced from the “very unhealthy” range inside DSRs and the “moderate” range outside Toronto DSRs to the “good” range, and in Windsor venues from the “unhealthy for sensitive groups” range to the “good” range post-ban. Pre-ban PPAH levels including those outside Toronto DSRs may be associated with cardiovascular injury. DSRs did not provide adequate protection from SHS. The Smoke-Free Ontario Act produced a significant and firm reduction in SHS exposure in venues both with and without DSRs.

Keywords:

• air particulate matter
• designated smoking rooms
• evaluation study
• particulate polycyclic aromatic hydrocarbons
• secondhand smoke
• smoking ban

ACKNOWLEDGMENTS

Field work was carried out by staff at the Research Services Unit, Dalla Lana School of Public Health, University of Toronto. This study was funded by the Ontario Ministry of Health Promotion.

Notes

^A P-value from the paired T-test on mean of means across venues using log-transformed data.

^B SE, standard error, design-based, reflecting variation across minute-by-minute values clustered within venues.

^C CI, confidence interval, calculated using bootstrapping method.

^A Numbers of patrons and smokers were averaged over 10-min observations.

^A Adjusted for patron density, temperature, and humidity.

^B Using log-transformed data; CI from the mixed model analysis using autoregressive covariance structure

^A PPAH (ng/m³) levels converted to PM_2.5 (μ g/m³) by divided the conversion factor of 0.83 and multiplied by 8 hr for work-related exposure to SHS (e.g., 1886.3 = 195.7÷ 0.83 × 8).

^B Exposure outside work calculated using 7.3 μ g/m³ averaged over 24 hr in downtown, Toronto (8.2 μ g/m³ in downtown, Windsor) for the year of 2006 (reported by the Ministry of Environment, Ontario, Canada), multiplied by 16 hr (e.g., 116.8 = 7.3 × 16).

^C PM_2.5 (μ g/m³) averaged over 24 hr calculated by average the work-related exposure and exposure outside work over 24 hr [e.g., 83.5 = (1886.3 + 116.8) ÷ 24].

^D AQI average over 24 hr calculated using PM_2.5 (μ g/m³) averaged over 24 hr multiplied by 100 and divided by 40 (e.g., 208.8 = 83.5 × 100 ÷ 40).