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Comparing Methods for the Real-Time Measurement of Secondhand Tobacco Smoke Particles. Neil E. Klepeis Visiting Scholar, Stanford University, Department of Statistics http://Klepeis.Net http://ExposureScience.Org neil@klepeis.net. Background Issues: Real-Time Particle Instruments.
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Comparing Methods for the Real-Time Measurement of Secondhand Tobacco Smoke Particles Neil E. Klepeis Visiting Scholar, Stanford University, Department of Statistics http://Klepeis.Net http://ExposureScience.Org neil@klepeis.net
Background Issues:Real-Time Particle Instruments • Can these instruments be used to characterize secondhand smoke? • Are they sensitive? • Are they convertible to standard measures? • Are they reliable and consistent?
Addressing the Issues • Field Studies of Secondhand Smoke Exposures • Controlled Studies of Exposure Factors • Controlled QA Studies Systematically Comparing and Evaluating Instruments
Real-Time Particle Monitoring Instruments, Part I A. Nephelometer (Radiance) B. Piezobalance (TSI/Kanomax) C. PAH (Ecochem) D. Laser Counter (GRIMM) E. CO (Langan)
Real-Time Particle Monitoring Instruments, Part II A. Laser Counter (Met-One) B. SidePak (TSI) C. PC/DC (Ecochem & Siegmann) D. Ultrafine 3007 CPC (TSI)
Reference Measure: Piezobalance Versus Filter Mass for Cigarettes and Incense
Cigarette Smoke Blowing Hookah Smoke Into Monitors
3D Monitoring Array to Study Outdoor Proximity and Wind Effects
Consistency and Correspondence • Do different monitors of the same type match each other? • Does the same monitor react the same on different days when using the same source and the same or different environmental conditions? • Can readings from one type of monitor be used to predict those of another? • Is the relationship between monitors of different types the same under different conditions, time scales, etc?
Four Suites of Side-by-Side QA Experiments (1). 31 Cigarette & Incense Experiments: Commercial Location; Grimm, Ecochem, Filters, Piezobalance (2). 7 Cigarette Experiments: Residential 44 m3 Bedroom; MIE DataRam, Ecochem, Piezobalance, Humidity, Temperature (3). 5 Cigarette Experiments: Residential 44 m3 Bedroom; Grimm, Ecochem, Piezobalance, Nephelometers. (4). 15 Cigarette Experiments: Residential 44 m3 Bedroom; Grimm, Ecochem, PC/DC, Piezobalance, Nephelometers, SidePak, Humidity, Temperature
Are Measurements Consistent Across Experiments onDifferent Days?
Can Measurements be Reliably Converted to Respirable Particle Mass (Piezobalance)?
Piezobalances and SidePak (Factory-Calibrated) Elapsed Minutes
Summary and Conclusions: Instrument Evaluation • Real-time instrument measurements can be related to standard methods and are generally sensitive, consistent, dependable, and quantitative indicators of tobacco smoke concentrations. • Matched instruments are very comparable, e.g., for use in studies of relative exposures • Factory calibrations of aerosol monitors cannot be assumed to be reliable for application to SHS • Two instruments analyzing different aerosol components and sizes may have a nonlinear relationship when including both fresh and aged aerosol • Light scattering instruments have a linear relationship to respirable mass, with an associated conversion factor • Instrument responses and relationships vary by composition and size of particle emissions • Relative humidity appears to have a small effect (50 to 75%)
Future Work on Real-TimeParticle Monitoring • Formalize Central Tendency and Variability in Instrument Interconversion Factors • More Side-by-Side Comparison of Instrument Responses in the Field • Consider Mixture of Cigarette Types • Use Real Smokers
Upcoming Report on Instrument Evaluation • Detailed description of all experiments • Results of all instrument comparisons • Best estimates of instrument conversion factors • Contact: neil@klepeis.net • Web: http://ExposureScience.Org
Last Words • Real Time Methods Allow us to Identify the Impact of Specific Minute-by-Minute Changes in Environmental Conditions and Human Behavior on Exposure • Unique Tool to Judge the Effectiveness of Exposure Reduction Measures • Immediate and Dramatic Feedback for Interventions • Development of Educational Materials
Acknowledgements • Wayne Ott, Stanford University • James Repace, Repace Associates • Paul Switzer, Stanford University • Lynn Hildemann, Stanford University • California Proposition 99, UCSF • Tobacco-Related Disease Research Program of California (TRDRP) • Flight Attendant Medical Research Institute (FAMRI) in Miami, FL • U.S. Environmental Protection Agency