Office of Technology Transfer – University of Michigan

Portable Instrument for Monitoring of Aerosol Acidity

Technology #2018-466

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Andrew P. Ault
Managed By
Jeremy Nelson
Senior Licensing Specialist, Physical Sciences & Engineering 734-936-2095
Patent Protection

US Patent Pending

Air pollution, specifically aerosols, is a major contributor to climate change and a detriment to overall human health. Aerosol acidity levels are vitally important for understanding atmospheric aerosol dynamics and secondary organic aerosol (SOA) formation, but the ability to monitor changes in acidity has remained largely elusive. Current technologies rely on modeling, estimation, or expensive instrumentation. As such, there is a significant unmet need for an affordable, accurate method for direct detection of atmospheric aerosol pH levels.

Facile Colorimetric Detection of Ambient Aerosol Acidity

Researchers at the University of Michigan have developed a technology that accurately monitors the pH of aerosols using relatively simple and common laboratory equipment. Using an impactor, relative humidity control, pH strips, a cell phone camera and simple image analysis software, users are able to gather accurate pH data on aerosols. No cumbersome filters or UV-Vis spectrometers are required. As such, this technique represents a significant departure from current methods and is fast, affordable, easy-to-use, and portable. Importantly, this system is amenable to a small box form factor for simplified use, remote operation in the field, and even automated monitoring (potentially as part of an IoT network). We expect this technology to be of value to everyone with a desire to understand aerosol formation and acidity from a scientific, regulatory, and environmental monitoring perspective.


  • Atmospheric aerosol acidity detection
  • Laboratory operation
  • Remote operation in the field
  • Automated monitoring


  • Accurate
  • Portable
  • Affordable¬†
  • Easy-to-use
  • Small form factor