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Environmental exposure and Toxicology

To support innovative and high impact research that advances policies to reduce environmental exposure to the toxic effects of tobacco smoke and tobacco smoke residue, and assesses and eliminates the environmental impact of cigarette waste; toxicology and the exposure science of new and emerging tobacco products.

Through this priority, we hope to fund research that helps reduce a range of types of environmental exposure and toxicology:


The emergence of e-cigarettes has complicated policies related to SHS exposure. There is need for further research on the health effects of exposure to e-cigarette aerosol and its constituents. Research in this area is urgently needed to fill this knowledge gap and assist policymakers in assessing the risks and benefits of e-chemicals and levels of nicotine in e-cigarette liquids.

Examples of relevant research topics include:

  • Toxicity levels, and markers of exposure to electronic cigarette constituents and aerosol
  • Current local policy approaches to controlling aerosol and tobacco smoke exposure in multiunit housing

  • Tobacco industry practices aimed at weakening public support for minimizing secondhand aerosol and tobacco smoke exposure in multiunit housing and indoor public spaces

  • How safe are e-cigarettes? A demonstration project approach to conduct research studies on use, and health effects in users and exposed non-users

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SHS is a Class A carcinogen and there is no risk-free exposure level to this indoor and outdoor pollutant. In order to support policies designed to minimize involuntary exposure to SHS, research is needed to understand SHS exposure and health risks in multiunit housing, casinos and the social-behavioral, economic and legal barriers to adoption of smoking bans in these areas.

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THS refers to the residual tobacco smoke pollutants that remain on surfaces and in dust after tobacco has been smoked, or are re-emitted back into the gas phase, or react with oxidants and other compounds in the environment to yield secondary pollutants. Toxic compounds so far identified in THS include many that are also present in SHS and mainstream smoke, as well as novel tobacco-specific carcinogenic nitrosamines. Emerging evidence from animal model studies alerts us that involuntary inhalation or dermal uptake of THS can be adverse to human health. Research on specific or unique biomarkers of THS exposure, and toxicological studies on exposure, dose, and response are needed. A better understanding of THS and its effects on human health and disease would address a critical need for information in the formulation of policies related to indoor air quality.

NOTE: TRDRP currently funds a statewide research consortium on thirdhand smoke. Applicants who plan to pursue THS research are required to design an approach that will benefit from the existing THS research capacity, infrastructure, and methodologies generated through this consortium. Through a review of Letters of Intent (LOI), proposals that appear to duplicate research being conducted by this THS Consortium will not be invited to submit full applications. Please
contact TRDRP staff for additional information.

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Cigarette waste remains the most common form of litter on US roadways and beaches. The environmental burden of cigarette butts is staggering; each year these are dumped by trillions, globally. California is no exception. Nearly all of cigarette filters are made of cellulose acetate, a non-biodegradable plastic that remains in the environment for a very long time. Ingested cigarettes are poisonous to children and adults as well as animals, and butt leachates are toxic to marine and freshwater fish. A new aspect of waste pollution arises from new product use, e.g. electronic cigarette components and their constituents and the environmental impact of the waste of these products.

New knowledge about the impact of tobacco product waste on the environment and the risks to human health can raise awareness and inform sound policies aimed at mitigating tobacco waste pollution and product use in sensitive environments.

Examples of relevant research topics include:

  • Environmental and economic impact of the production, sale, and use of new products and its related waste
  • New policy approaches to reduce or mitigate tobacco product waste at the municipal, county, or state levels
  • Exposure and toxicity of cigarette butt and other new tobacco product waste.

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