A Review of Patents on Engine Exhaust Particulate Matter Samplers

The purpose of this paper is to review particulate measurement systems based on the technologies available from the online database maintained by the United States Patents and Trademark Office. The most significant patents are evaluated based on key features and principles such as gravimetric, optical, and electrostatics. It was found that scientists are constantly improving the instruments using different physical characteristics related to the exhaust. The paper identifies knowledge gaps that could be used to develop new inventions.