Grantee Research Project Results

Final Report: Indoor Formaldehyde Detection by a Low-Cost Chemical SensorBasedonOrganic Nanofibers

EPA Contract Number: 68HERD19C0002
Title: Indoor Formaldehyde Detection by a Low-Cost Chemical SensorBasedonOrganic Nanofibers
Investigators: Later, Douglas W
Small Business: Vaporsens, Inc.
EPA Contact: Richards, April
Phase: II
Project Period: December 1, 2018 through November 30, 2020 (Extended to November 30, 2021)
RFA: Small Business Innovation Research (SBIR) - Phase II (2018) Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Air and Climate

Description:

Formaldehyde is a suspected carcinogen and is emitted from many common materials found in indoor environments, including laminate flooring, paint, varnish, and engineered wood products. The National Institute for Occupational Health and Safety published a recommended exposure limit of 16 ppb. Measurement of formaldehyde at concentrations this low is typically performed high performance liquid chromatography and is inaccessible to most consumers. Sensors for formaldehyde are generally based on electrochemical cells, which generally do not have adequate sensitivity, are inaccurate, and can be cross-reactive to common chemicals like ethanol. There is a need for accurately measuring formaldehyde in indoor environments.

Summary/Accomplishments (Outputs/Outcomes):

Vaporsens produces sensors that are based on organic nanofibers. In this work, new nanofiber materials were synthesized for high sensitivity to formaldehyde and evaluated for sensitivity to formaldehyde, robustness against humidity (up to 70% RH), cross reactivity to common interferents, reproducibility, and lifetime. A prototype was developed for ambient monitoring. 

Conclusions:

 A preliminary model for predicting concentration from sensor responses had a mean absolute percent error of 30% and was not affected by humidity. No cross-reactivity was observed for six common interferents including ethanol. A low cross-reactivity 0f 0.15 ppb/ppb was measured for sulfur dioxide. A reproducibility study revealed that the sensors could be manufactured with <10% variability between batches.  A lifetime study simulated aging for ~2 years, after which the sensors still functioned largely as intended but with reduced repeatability. Prototypes were developed and tested in simulated real-world conditions in the laboratory.

Indoor air quality represents a $9.2B market in the United States in 2020, with a significant portion accounted for by monitoring equipment and devices. Over the past three years, Vaporsens has researched, evaluated, and began developing a solution for the unmet market need of a small, affordable, and reliable device to accurately detect the presence of formaldehyde. Vaporsens has directly interviewed over 500 interested and related persons, with over 100 specific to formaldehyde detection. Vaporsens continued to develop robust solutions that can be commercialized as a stand-alone handheld solution, or as a module that could be integrated into other devices. Vaporsens has also continued to engage with several potential partners and distribution channels to provide these products to consumers. In April of 2020, Vaporsens merged with Gentex Corporation, and now has a significant platform to execute our commercialization strategy. With the positive results from the development and testing performed with the support of this SBIR contract, Vaporsens is well positioned to capture this market opportunity with its formaldehyde sensors.

SBIR Phase I:

Indoor Formaldehyde Detection by a Low-Cost Chemical Sensor Based on Organic Nanofibers  | Final Report