THS Chemistry: Exposure assessment, detection & remediation
Abstracts
Initial Award Abstract |
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Our group has contributed to the development of the Thirdhand Smoke (THS) Consortium by describing indoor chemical processes that dominate exposures to THS. We have studied the critical role of indoor reactions of THS constituents with oxidants and nitrosating agents commonly found indoors. The identification and quantification of inhalable THS constituents enabled the assessment of their health impacts. Sampling and analytical methods were developed to expand the scope of THS constituents that can be measured. More recently, we initiated a study to evaluate the efficiency and potential risks associated with releasing high levels of ozone as a THS remediation approach. We have also collaborated with other Consortium partners in the evaluation of THS biological effects. On this new phase of the Consortium, we intend to extend our research on these areas by: Aim 1: Quantify intake of carcinogenic tobacco-specific nitrosamines (TSNAs) via the main exposure routes (dermal, dust ingestion, inhalation), to better implement protective measures and THS remediation strategies. Our approach will involve a combination of experimental methods to assess dermal uptake, and modeling incorporating recently published information on TSNAs levels in THS. We hypothesize that TSNAs can form directly on the skin by nitrosation of nicotine, and contribute significantly to total exposure to these harmful compounds. Aim 2: Develop a THS diagnostic tool for untrained non-professional users, based on measurement of airborne nicotine. Quantifying accurately very low levels of nicotine in indoor air is a useful tool to assess THS contamination, because it integrates emissions from multiple sources. Samplers will trap nicotine on a bisulfate-coated filter connected to a miniature battery-operated pump and flow sensor with continuous logging capabilities. The method will be validated in the lab, and deployed alongside other THS diagnostic tools in field measurements led by SDSU. We intend to increase our ability to detect trace levels of nicotine by 1-2 orders of magnitude with respect to the current practice using bisulfate-coated filters. Aim 3: Contribute to Consortium-wide efforts to assess remediation strategies by evaluating the efficacy of carpet replacement in THS-contaminated homes that are being cleaned and conditioned for rent or sale. Air and surface samples will be measured before and after a new carpet is installed, to quantify the impact of source elimination. The THS-contaminated carpet and padding materials will be installed at LBNL's room-sized chamber and used in ozonation experiments. An ozone generator commonly used in homes by companies providing cleaning and restoration services will be used to assess short- and long-term effects, including formation of airborne and surface-bound oxidation byproducts. |
