Measurement of Volatile Organic Carbon (VOC) inside Masks: Are We Breathing Poor Quality Air?

Abstract

The COVID-19 pandemic has dramatically increased the number of face masks being worn in order to prevent the spread of the SARS-CoV-2 virus. While face masks are effective for protecting against harmful compounds in the environment from the outside, rebreathing the air inside the mask may potentially be harmful. To measure the quality of air accumulated during mask usage, we developed an instrument using an Arduino microcontroller connected to a Bosch BME680 sensor to measure volatile organic carbon (VOC), humidity, and temperature inside and outside of three different masks: Surgical, Arun KN95, and Honeywell NIOSH N95. During the experiment, all three parameters immediately increased to a constant value and did not decrease during breathing trails for 5, 10, and 15 minutes into the mask. During the breathing trails, the air quality was found to be moderate and never changed. The total VOC and humidity increased linearly (R squared > 0.997) with time for all three masks. Additionally, the sensor was calibrated at 37 C with acetone vapor to calculate the VOC (in micrograms/L or ppb) ketone-basis (kbVOC). The calibration shows a response factor of 1.08E-09 M/ohm or 0.063 micrograms/L and a detection limit of 132 ppb at a signal-to-noise ratio of 64.3. The kbVOC values were found by multiplying the response factor with the VOC values during breathing trials. When plotted, the kbVOC values fluctuated between 15 to 20 ppb, indicating poor air quality inside our masks. Further calculations of VOC and humidity permeability showed the face masks used are 80-90 percent permeable. This study raises questions about the quality of air that we breathe inside our face masks and the subsequent health risks associated with it. Although the present study was conducted by a healthy person (SO), it can be extended to people with various conditions, such as stress or diseases, where higher VOC concentrations are produced.