"Portable, Ambient PM2.5 Sensor for Human and/Or Animal Exposure Studies"

A field portable device for logging PM2.5 mass concentration data has been developed. The device combines the Arduino microprocessor with an SD card, an Sharp DN7C3CA006 optical dust monitor, and 10 000 mAh battery. The PM2.5 dust sensor uses a virtual impactor to size select particles prior to illuminating them with an LED. The LED is triggered by a circuit controlled with the Arduino. Nephelometric detection at 120° referenced to incidence is employed. The voltage signal reported by the dust sensor is converted to PM2.5 mass thru calibration onboard the Arduino. Data points can be saved to the SD card as rapidly as 0.3 s, although averaging signals over 60 s produced more optimal detection limits. For a 60 s average, the PM2.5 mass limit of detection was 9 µg/m3 indicating the sensor will be useful for monitoring human exposure to fine particles. Portable exposure monitoring has been demonstrated with the sensing platform as several individuals carried the device with them during da