Towards the World's Smallest Gravimetric Particulate Matter Sensor: A Miniaturized Virtual Impactor with a Folded Design

• Published in: Sensors (Basel, Switzerland) Vol. 22; no. 5; p. 1727
• Main Authors: Singh, Navpreet, Elsayed, Mohannad Y, El-Gamal, Mourad N
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 23.02.2022; MDPI
• Subjects: 3D printing; Air Pollutants - analysis; Air Pollution; Aluminum; Health aspects; Humans; Laboratories; MEMS; Miniaturization; Outdoor air quality; particulate matter; Particulate Matter - analysis; PM2.5; Pollutants; Public health; Sensors; virtual impactor; Canada; virtual impactor; particulate matter; MEMS; sensors; 3D printing; PM2.5
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s22051727

The increasing air pollution across the globe has given rise to a global health crisis that is increasing at an alarming rate. Every year, millions of people lose their lives due to health risks caused by air pollutants. Hence, there is a pressing need for better solutions to accurately measure the amount of air pollution. This work is aimed at designing a highly compact, accurate, low-cost, self-resettable, and easy-to-use gravimetric-based particulate matter sensor solution for portable applications. Previous attempts have failed to realize true miniaturization, due to the size constraints of the needed-a mechanism that segregates the particulate matters based on their sizes. Our complete particulate matter sensor solution consists of three components (i) a piezoelectric resonating membrane, (ii) a virtual impactor, and (iii) a thermophoretic mechanism to reset the sensor. This paper presents a novel design of the virtual impactor, based on a folded configuration. This helps realize the entire system in a volume of 20 mm × 20 mm × 10 mm. We report here the design, working principles, fabrication, and experimental results of the virtual impactor.