AirPen: Wearable Particle and Gas Monitor

Quantify Personal Exposure to Fine Particulate Matter and Volatile Organic Compounds

At a Glance

Researchers at Colorado State University have developed a personal wearable monitor that quantifies exposure to gases (volatile organic compounds, VOC) and particulate matter (PM) dubbed the AirPen. The small, quiet, wearable design allows personal VOC and PM exposures to be measured across distinct microenvironments, including a person’s home, place of work or school, transit and commuting paths, and other non-residential indoor environments. The AirPen can be used to advance our understanding of personal exposure to air pollution as a function of time, location, source, and activity, even in the absence of detailed activity diary data.



Millions of people suffer from adverse health outcomes associated with exposure to indoor and outdoor air pollution. The exponential growth in air pollution research over the past several decades has created a growing need (and market) for improved exposure measurement technologies that are tailored to diverse air pollution mixtures. Volatile organic compounds (VOCs) that contribute to these mixtures include carcinogens, neurotoxicants, and endocrine-disrupting compounds, as well as compounds linked to unhealthy respiratory and immune responses, especially among highly susceptible populations (e.g. children, the elderly, and those with pre-existing diseases). Exposure to VOCs is also a pressing concern in occupational settings, especially for emergency first responders (e.g. immediately following natural disasters and accidental chemical releases), workers involved in hazardous site assessment, and long-term disaster response teams (e.g. mold remediation following flooding events). Current technologies used to assess exposure have typically been designed for a single sample type (e.g., particle- vs gas-phase and sometimes even a single gas-phase species).


CSU researchers developed a small, quiet, self-contained wearable monitor that combines a multitude of sensors with the sampling technology needed to quantify personal exposures to particle- and gas-phase air pollutants simultaneously. This monitor, called the “AirPen”, samples PM onto a filter and volatile organic compounds (VOCs) onto a thermal desorption tube while logging time-resolved data on PM concentration, total VOC (TVOC) concentration, temperature, humidity, light intensity, location, and motion. These features can be leveraged to identify locations, sources, and activities across multiple microenvironments associated with the largest personal exposures to PM and VOCs.


  • Small, light, quiet
  • Less expensive and easy to use
  • Single piece construction eliminates need for tubing, reducing restriction of movement on wearer
  • Time/location exposure measurements


  • Personal environmental air pollution exposure monitoring.
  • Long term disaster response teams.
  • Emergency first responders
  • Hazardous site assessment workers.
Last Updated: January 2024
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