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Monitoring Airborne Levels of Outdoor and In-Vehicle Secondhand Tobacco Smoke. Neil E. Klepeis, Ph.D. Human Exposure Research Associate Stanford University, Stanford, CA http://klepeis.net, http://exposurescience.org. Why Monitor Secondhand Smoke?. Judge severity of exposure
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Monitoring Airborne Levels of Outdoor and In-Vehicle Secondhand Tobacco Smoke Neil E. Klepeis, Ph.D. Human Exposure Research Associate Stanford University, Stanford, CA http://klepeis.net, http://exposurescience.org
Why Monitor Secondhand Smoke? • Judge severity of exposure • Communicate risks • Encourage smoking restrictions and bans • Identify exposure reduction measures • Establish disease association (epidemiology)
Why Monitor Outdoors andin Cars? • Last frontiers for smoking bans • Very few studies available • How high can outdoor levels really be? • Practical Questions • What if I open my car window or use the ventilation during smoking? • What if I smoke near my child outdoors?
What's in this Talk? • Introduce Air Monitoring Instruments • New Outdoor SHS Surveys and Experiments • New In-Vehicle SHS Experiments • Predictive Modeling of SHS Exposure and Risk
Portable Airborne Particle Monitoring Instruments A. Laser Counter; B. SidePak Laser Photometer; C PC/DC Monitor; D. Condensation Nucleii Counter A. Nephelometer; B. Piezobalance; C PAH Analyzer; D. Laser Particle Counter; E. CO Sensor
Outdoor Secondhand Smoke Monitoring in Sidewalks Cafes, Parks, Pubs, Restaurants
Visits to Sidewalk Cafes & Restaurants • 10 Locations • 2000 minutes of continuous measurements • Natural Human Smokers • Controlled Smoking
Experiments with a Real Smoker SidePak Monitor Air Speed Monitor Air Speed Monitor
Elevated Levels Near the Smoker 0.5 m 252 mg/m3 0.5 m 233 mg/m3 0.5 m 222 mg/m3 0.8 m 127 mg/m3 2.0 m 41 mg/m3 2.0 m 14 mg/m3 3.7 m 14 mg/m3 3.7 m 5 mg/m3
0.3 m 582 mg/m3 0.6 m 130 mg/m3 0.9 m 127 mg/m3 0.6 m 2 mg/m3 1.2 m 41 mg/m3 2.7 m 13 mg/m3 Elevated Downwind Levels from a Smoker
Controlled Patio Experiments Air Monitor Assemblies on Either Side of a Burning Cigarette
Summary of Outdoor Results • Being downwind from a smoker is the critical factor • Levels drop off dramatically beyond 2 meters from a smoker – although levels can still be detected as far away as 9 meters or more. • Being close to and downwind from an active smoker can lead to very high transient levels • Short-term outdoor levels can exceed secondhand smoke levels measured inside smoking cars and houses
In-Vehicle Secondhand Smoke Monitoring in Passenger Cars and SUV's
Vehicle Air Exchange Rates • 85 Air Changes • Five Vehicles • Tracer Gas Releases • Five Driving Speeds • Window Positions • Ventilation Settings
Experiments In Cars with Smokers • 3 Rented Vehicles • 2 Smokers • 14 Cigarettes • Particle/CO monitoring • Five Speeds • Window Positions • Ventilation Settings
A Levels Inside a Car with a Smoker B A. Ford Taurus, 20 mph B. Ford Taurus, 60 mph
Predicting In-Vehicle Levels Levels are well predicted using a mathematical mass balance model.
Simulation of Levels in a Car Rapid Feedback and Flexible Educational Tool
Summary of In-Vehicle Results • Opening windows increases the air exchange rate by a factor of 10 • Air exchange rate of car increases with speed • Smoking in a closed car results in extremely high levels that are about 10 times higher than those measured in smoking homes • Short-term levels with windows open or active ventilation can still approach levels found in smoking homes • Levels in cars can be characterized using mathematical models
Practical Modeling of Daily (24-h) Exposure and Risk: Fine Particles Ambient Outdoors Car USEPA Unhealthy 17 Cigarettes 2 Cigarettes PM-2.5 Sens. People Downwind Closed/Moving Standard 106 mg/m3 68 mg/m3 65 mg/m3 41 mg/m3
Resources ExposureScience.Org Downloadable Reports, Articles, and Software Related to Secondhand Tobacco Smoke Exposure in Cars, Homes, and the Outdoors SimSmoke.Org On-line Simulation of Secondhand Smoke Exposures in Indoor and Outdoor Settings
Acknowledgments • Wayne Ott, Stanford University (Co-Investigator) • Paul Switzer, Stanford University (Principle Investigator) • Grant from the Flight Attendant Medical Research Institute (FAMRI) • Grant from California Proposition 99 • Past Grant from Tobacco-Related Disease Research Program (TRDRP)