Developing a Low-Cost Wearable Personal Exposure Monitor for Studying Respiratory Diseases Using Metal-Oxide Sensors

Kyle R. Mallires, Di Wang, Vishal Varun Tipparaju, Nongjian Tao

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Global industrialization and urbanization have led to increased levels of air pollution. Those with respiratory diseases, such as asthma, are at the highest risk for adverse health effects and reduced quality of life. Studying the relationship between pollutants and symptoms is usually achieved with data from government air quality monitoring stations, but these fail to report the spatial and temporal resolution required to track a person's true exposure, especially when the majority of their time is spent indoors. We develop and build eight wrist-worn wearable devices, weighing only 64 g, to measure known asthma symptom triggers: ozone, total volatile organic compounds, temperature, humidity, and activity level. The devices use commercial off-the-shelf components, costing under $150 each to build. This report focuses on the design, calibration, and testing of the devices. Emphasis is placed on the calibration of a metal-oxide-semiconductor gas sensor for detecting ozone, which is a difficult task because of the large variations in ambient temperature and humidity found when using a wearable device. Examples of testing the devices in four real environments are also discussed: 11 days inside a well-ventilated laboratory, ten days outdoors during the summer, alternating the devices between indoor and outdoor environments to examine their response to quickly changing environments, and a field test where scripted activities are performed for a full day. The work demonstrates a wearable device for environmental health studies and addresses the challenges of existing sensors for real-world applications.

Original languageEnglish (US)
Article number8717689
Pages (from-to)8252-8261
Number of pages10
JournalIEEE Sensors Journal
Issue number18
StatePublished - Sep 15 2019
Externally publishedYes


  • Air quality
  • MOS
  • asthma
  • calibration
  • environmental monitoring
  • gas sensor
  • metal oxide semiconductor
  • ozone
  • personal monitoring
  • volatile organic compounds
  • wearable device

ASJC Scopus subject areas

  • Instrumentation
  • Electrical and Electronic Engineering


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