A Formaldehyde Dosimeter for Personal Exposure Assessment

DESCRIPTION provided by applicant The air we breathe can contain dozens of toxins The National Institute of Environmental Health Sciences NIEHS strategic plan for includes a major focus on andquot enhancing our ability to quantify individual exposures and responses to environmental toxins andquot Similarly the US Environmental Protection Agency EPA is increasing its emphasis on community monitoring so that citizens may better understand their exposures to toxins However equipping large numbers of individuals and or geographic sites with available monitoring equipment capable of accurately measuring low levels of toxins would be prohibitively expensive Therefore affordable devices capable of measuring personal exposures to toxic gases are urgently needed Moreover available andquot simpleandquot toxic gas monitors have presented difficulties of operation and interpretation when deployed by lay personnel for community monitoring initiatives Therefore personal exposure monitors must also be easy to use and interpret if personal monitoring is to be widely adopted One air pollutant that is challenging to measure affordably at low levels with specificity and accuracy is formaldehyde HCHO This carcinogen is emitted from building materials among other sources and can pollute homes and workplaces where the materials are installed or manufactured Providing simple affordable means of monitoring HCHO exposure would provide citizens with better actionable information epidemiologists with better data with which to assess health risks and regulators with information needed to develop effective defensible policies Platypus Technologies has developed an approach to monitoring HCHO exposure that combines the companyandapos s proprietary liquid crystal LC sensing platform with a novel sensing mechanism The platform is amenable to zero power readouts and the sensors are inherently small and light weight facilitating comfortable deployment on people Platypus has commercialized the ClearSense tm hydrogen sulfide dosimeter based on LC technology for the industrial hygiene market and now proposes to leverage this expertise for the more challenging task of HCHO detection The LC sensing platform is uniquely amenable to a novel surface chemistry strategy for detecting HCHO that is designed to improve specificity over currently available sensors The strategy involves fabricating a chemically reactive surface on which LCs align parallel to it On exposure to HCHO the LCs realign perpendicular to the surface This realignment causes sensors to change from bright to dark when viewed through crossed polarizers The long term goal is a chemical dosimeter product for HCHO suitable for personal exposure monitoring To minimize fabrication costs and improve performance for long term monitoring we propose to modify sensor design from the Clear Sense product concept by i supplanting the use of gold on glass sensor surfaces with saline on glass to save costs and extend sensor stability ii reducing sensor surface area further reducing costs and iii replacing the LCs traditionally used for sensors with LCs that have greater resilience to changes in temperature and moisture an option not previously possible that is afforded by the novel detection chemistry PUBLIC HEALTH RELEVANCE The National Institute of Environmental Health Sciences NIEHS strategic plan for includes a major focus on andquot enhancing our ability to quantify individual exposures and responses to environmental toxins andquot Equipping large numbers of individuals with reliable toxics monitoring equipment would provide valuable exposure data for individuals for epidemiologists and for regulators but is currently prohibitively expensive and for many overly complicated We propose to determine the feasibility of a novel strategy for fabricating low cost light weight dosimeters for personal monitoring of exposure to the carcinogen formaldehyde so that broad communities regulators and epidemiologists may better understand community and individual health risks