Presentation on theme: "Comparing Methods for the Real- Time Measurement of Secondhand Tobacco Smoke Particles Neil E. Klepeis Visiting Scholar, Stanford University, Department."— Presentation transcript:
Comparing Methods for the Real- Time Measurement of Secondhand Tobacco Smoke Particles Neil E. Klepeis Visiting Scholar, Stanford University, Department of Statistics http://Klepeis.Nethttp://ExposureScience.Orgneil@klepeis.net
Background Issues: Real-Time Particle Instruments n Can these instruments be used to characterize secondhand smoke? n Are they sensitive? n Are they convertible to standard measures? n Are they reliable and consistent?
Addressing the Issues n Field Studies of Secondhand Smoke Exposures n Controlled Studies of Exposure Factors n Controlled QA Studies Systematically Comparing and Evaluating Instruments
Consistency and Correspondence n Do different monitors of the same type match each other? n Does the same monitor react the same on different days when using the same source and the same or different environmental conditions? n Can readings from one type of monitor be used to predict those of another? n 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 m 3 Bedroom; MIE DataRam, Ecochem, Piezobalance, Humidity, Temperature (3). 5 Cigarette Experiments: Residential 44 m 3 Bedroom; Grimm, Ecochem, Piezobalance, Nephelometers. (4). 15 Cigarette Experiments: Residential 44 m 3 Bedroom; Grimm, Ecochem, PC/DC, Piezobalance, Nephelometers, SidePak, Humidity, Temperature
Summary and Conclusions: Instrument Evaluation n Real-time instrument measurements can be related to standard methods and are generally sensitive, consistent, dependable, and quantitative indicators of tobacco smoke concentrations. n Matched instruments are very comparable, e.g., for use in studies of relative exposures n Factory calibrations of aerosol monitors cannot be assumed to be reliable for application to SHS n Two instruments analyzing different aerosol components and sizes may have a nonlinear relationship when including both fresh and aged aerosol n Light scattering instruments have a linear relationship to respirable mass, with an associated conversion factor n Instrument responses and relationships vary by composition and size of particle emissions n Relative humidity appears to have a small effect (50 to 75%)
Future Work on Real-Time Particle Monitoring n Formalize Central Tendency and Variability in Instrument Interconversion Factors n More Side-by-Side Comparison of Instrument Responses in the Field n Consider Mixture of Cigarette Types n Use Real Smokers
Upcoming Report on Instrument Evaluation n Detailed description of all experiments n Results of all instrument comparisons n Best estimates of instrument conversion factors n Contact: firstname.lastname@example.org n Web: http://ExposureScience.Org
Last Words n Real Time Methods Allow us to Identify the Impact of Specific Minute-by- Minute Changes in Environmental Conditions and Human Behavior on Exposure n Unique Tool to Judge the Effectiveness of Exposure Reduction Measures n Immediate and Dramatic Feedback for Interventions n Development of Educational Materials
Acknowledgements n Wayne Ott, Stanford University n James Repace, Repace Associates n Paul Switzer, Stanford University n Lynn Hildemann, Stanford University n California Proposition 99, UCSF n Tobacco-Related Disease Research Program of California (TRDRP) n Flight Attendant Medical Research Institute (FAMRI) in Miami, FL n U.S. Environmental Protection Agency