Abstract View
Long-term Evaluation of Low-Cost Air Sensors to Measure Indoor and Outdoor Particulate Matter in a Polluted Environment: Strengths and Limitations
JAEBIN JU, Linh Luu, Danielle Rocco, Esther Morales, Daniel B. Curtis, California State University, Fullerton
Abstract Number: 403
Working Group: Instrumentation and Methods
Abstract
There has been a recent increase in interest in the field of low-cost air sensors, particularly PurpleAir sensors, due to their low cost, ease of use, ability to share the data online in real time, high time and spatial resolution, and ability to be deployed over wide geographical areas. These advantages have led to wide adoption of the sensors, with over 10,000 PurpleAir sensors deployed in the United States, especially in certain areas, such as California. Many studies have been conducted to test the accuracy and reliability of the sensors in controlled environments and there are increasing number of field studies being conducted. Although several studies have shown that the raw accuracy of low-cost sensors is questionable, the high precision of the sensors may allow for intercomparison studies between sensors. However, there have been only few studies studying performance of the sensors indoors and outdoors at the same location.
This study evaluated the long-term reliability of deploying PurpleAir sensors to compare the indoor and outdoor air quality at California State University, Fullerton, located in a suburban area within the Los Angeles metropolitan area in Southern California. Two PurpleAir sensors were collocated, one indoors and one outdoors, for a two-year period ranging from January 1, 2019 to December 31, 2020, including several very high particle concentration events such as fireworks from the July 4 holidays and several wildfire plumes in the area. A correlation between the outdoor and indoor concentrations was observed, but at roughly half the concentration indoors. In addition, short-term pollution events, suspected to be fireworks from a nearby theme park, were observed. It is shown that after time-averaging the measurement to one-hour periods that the short-term events were not observed, indicating that the high time-resolution of the PurpleAir sensors may allow for better understanding of transient pollution events than reference monitors.