Micro Quartz Tuning Fork-Based PM2.5 Sensor for Personal Exposure Monitoring

A portable, wireless, and cost-effective PM
_2.5
sensor based on micro quartz tuning fork (MQTF) has been developed. Coated with repositionable polymer glue for effective absorption of PM
_2.5
and with the help of innovative nozzle inlet, the MQTF-based sensor is highly sensitive to PM
_2.5
in the detection range of 2 ~ 2000 μg/m
³
with high stability. The sensor response, change rate of the MQTF frequency, shows linear relationship with PM
_2.5
concentration from 6 to 100 μg/m
³
at the flowrate of 1.7 L/min, which is a typical range of PM
_2.5
concentration in ambient air. By integrating the repositionable adhesive coated MQTF, driving and detection circuit, PM
_2.5
filter, sampling system, and a smartphone with Bluetooth and home-developed app, the MQTF-based sensor is assembled for personal PM
_2.5
exposure monitoring. Furthermore, field tests show that the PM
_2.5
concentration readings from MQTF-based sensor and commercial PM monitor correlate very well with each other, which indicates the high accuracy and reliability of the MQTF-based sensor.