Performance of low-cost PM_2.5 monitors during the HOMEChem experiment

Area of Science:

• Environmental health science
• Air quality monitoring
• Sensor technology

Background:

• Indoor environments are significant sources of fine particulate matter (PM2.5) exposure.
• Variability in PM2.5 emissions necessitates accurate monitoring solutions.
• Research-grade instruments are costly, driving interest in low-cost alternatives.

Purpose of the Study:

• To evaluate the accuracy and time response of consumer-grade PM2.5 monitors.
• To compare low-cost monitors against research-grade instrumentation under controlled indoor conditions.
• To identify biases and limitations of popular low-cost PM2.5 sensors.

Main Methods:

• A controlled field study was conducted in a test house.
• Three consumer-grade (Air Quality Egg, PurpleAir, Speck) and one research-grade (WashU) PM2.5 monitors were used.
• Experimental data were collected from various indoor sources, including cooking events.

Main Results:

• Speck demonstrated the best accuracy, while WashU showed the best time response.
• Plantower-based monitors, common in consumer devices, tended to overestimate PM2.5 concentrations, especially during cooking.
• Variations in performance were observed even among monitors with the same sensor type, suggesting other factors influence readings.

Conclusions:

• Low-cost PM2.5 monitors exhibit performance differences, with potential for overestimation of indoor pollution.
• Consumers and researchers should be aware of these biases when interpreting data from devices like Plantower-based monitors.
• Understanding monitor limitations is crucial for accurate exposure assessment and effective air quality management.