CO2 Ventilation Quality Sensor
Asiful Asif, Anna-Victoria Berkibekyan, Daniel Diaz, Frank Gomez, Sakshi Patel
Los Angeles City College, Los Angeles, California
Moving forward with the Covd-19 crisis, it’s important to understand what environments make individuals more susceptible to contracting the virus. Studies have shown that covid is easier to transmit in indoor settings with poor ventilation than the outdoors, where there is proper ventilation. To investigate this, a portable, arduino-based CO2 measuring device with data logging capabilities was developed. Experiments were designed to measure the ambient CO2 levels under varying levels of ventilation. The design of the device and an analysis of the data will be presented.
Figure 2 shows an area chart of the collected CO2 data (over a period of approximately 2 minutes with 114 data points). Sensor readings were first taken indoors, then outdoors, and once again indoors. The data indicates a large discrepancy between the indoor (with low ventilation) and outdoor CO2 levels. Figure 3 shows an area chart of the collected CO2 data (over a period of approximately 23 minutes with 1427 data points). Sensor readings were taken indoors, initially under low ventilation, and then under increased ventilation. After increased ventilation, CO2 levels dropped significantly and matched closely with that of the outdoors.
A portable CO2 measuring device, based on an Arduino UNO microcontroller, was developed. The device consists of a carbon dioxide sensor that includes temperature and humidity measuring capabilities (Sensitron SCD30), a real time clock and SD card module (OSEPP RTCSD-01), and a 16x2 character LCD display (LCM1602C). The CO2 sensor works under a nondispersive-infrared principle and measures with a range of 400 ppm to 10000 ppm and with an accuracy of +/- 30 ppm. The device was interfaced through the Arduino platform and programmed to recurrently measure the ambient CO2 levels every two seconds and write it onto the SD memory card. The components were connected through a breadboard with jumper wires. The device is powered through a 4xAA battery holder or a USB connection. The device is shown in Figure 1.
Increasing ventilation, in the case of opening the windows of a room, led to a significant decrease in the concentration of indoor CO2 levels, which decreases the likelihood of other airborne particles such as aerosolized coronavirus, and diluted the air with that of the outdoors. The device could serve useful to measure the quality of ventilation in indoor spaces such as homes, offices, and small businesses where people might gather. Understanding the air quality can enable people to make safer decisions on what spaces they can safely gather.
Because aerosolized coronavirus can remain in the air for up to three hours [1], it’s important to maintain proper outdoor air dilution of indoor air to decrease the concentration of airborne particles. Carbon dioxide is often used as an indicator to measure the quality of ventilation in indoor settings. Generally, indoor CO2 levels of 400 ppm to 1099 ppm is synonymous with adequate ventilation, levels of 1100 ppm to 1599 ppm are synonymous with poor levels of ventilation, and levels of 1600 ppm and over is synonymous with bad ventilation. We expect to see CO2 levels drop in rooms when increasing ventilation to match closely with the CO2 level outdoors. We developed a device that measures and records CO2 levels in real time.
1] Çetin, Mehmet & Sevik, Hakan & Işınkaralar, Kaan. (2017). Changes in the particulate matter and CO2 concentrations based on the time and weather conditions: The case of Kastamonu. Oxidation Communications. 40. 477-485.
[2] Wei, Tingting & Meng, Tang. (2018). Biological Effects of Airborne Fine Particulate Matter (PM 2.5 ) Exposure on Pulmonary Immune System. Environmental Toxicology and Pharmacology. 60. 10.1016/j.etap.2018.04.004.
[3] Newman, S., Xu, X., Gurney, K. R., Hsu, Y., Li, K., Jiang, X., . . . Yung, Y. L. (2015, 10). Toward consistency between bottom-up CO2 emissions trends and top-down atmospheric measurements in the Los Angeles megacity. Atmospheric Chemistry and Physics Discussions, 15(20), 29591-29638. doi:10.5194/acpd-15-29591-2015
References
Abstract
Instroduction
Methods
Results
Conclusion
Increasing Ventilation
Indoors
Outdoors
Indoors
Figure 1
Figure 2
Figure 3
Arduino UNO
LCD DIsplay
Real TIme Clock and SD Card
CO2 Sensor