Secondhand smoke transfer in multiunit housing.

INTRODUCTION The home can represent a significant source of secondhand smoke (SHS), especially for individuals who live in close proximity to one another in multiunit housing (MUH). The objective of this study was to quantify real-time SHS transfer between smoke-permitted and smoke-free living units within the same MUH structure. METHODS Air monitors were used to assess PM₂.₅, an environmental marker for SHS, in 14 smoke-free living units and 16 smoke-permitted units within 11 MUH buildings in the Buffalo, New York, area between July 2008 and August 2009. Air monitors were operated concurrently in both smoke-permitted and smoke-free units within each building. When feasible, additional monitors were stationed in shared hallways and on outdoor patios. Participants completed logs to document activities that could affect air quality. RESULTS Evidence of SHS transfer from smoke-permitted units was detected in 2 of the 14 smoke-free units and 6 of the 8 hallways. Real-time PM₂.₅ plots and participant logs suggest that SHS transfer is a function of many determinants, including ventilation and proximity between units. Following stratification by time of day, median PM₂.₅ levels were greatest between 4:00 PM and 11:59 PM but varied by location: 10.2 μg/m³ in smoke-free units, 18.9 μg/m³ in hallways, and 29.4 μg/m³ in smoke-permitted units. CONCLUSIONS This study documents SHS incursions from smoke-permitted units into smoke-free units and adjacent hallways within the same building. Since many factors appear to impact the amount of SHS transfer between these areas, the implementation of a smoke-free building policy represents the most effective way to ensure that residents of MUH units are not exposed to SHS.