Response of consumer and research grade indoor air quality monitors to residential sources of fine particles

Abstract

The ability to inexpensively monitor PM to identify sources and enable controls would advance residential indoor air quality (IAQ) management. Consumer IAQ monitors incorporating low-cost optical particle sensors and connections with smart home platforms could provide this service if they reliably detect PM in homes. In this study, particles from typical residential sources were generated in a 120 m laboratory and time-concentration profiles were measured with 7 consumer monitors (2-3 units each), 2 research monitors (Thermo pDR-1500, MetOne BT-645), a Grimm Mini Wide-Range Aerosol Spectrometer (GRM), and a Tapered Element Oscillating Microbalance with Filter Dynamic Measurement System (FDMS), a Federal Equivalent Method for PM . Sources included recreational combustion (candles, cigarettes, incense), cooking activities, an unfiltered ultrasonic humidifier, and dust. FDMS measurements, filter samples, and known densities were used to adjust the GRM to obtain time-resolved mass concentrations. Data from the research monitors and 4 of the consumer monitors-AirBeam, AirVisual, Foobot, Purple Air-were time correlated and within a factor of 2 of the estimated mass concentrations for most sources. All 7 of the consumer and both research monitors substantially under-reported or missed events for which the emitted mass was comprised of particles smaller than 0.3 μm diameter.

Wildfire Smoke Adjustment Factors for Low-Cost and Professional PM2.5 Monitors with Optical Sensors

“…Collections of low-cost air quality monitors that are being deployed throughout the world [30][31][32][33] could be used to track wildfire smoke events. However, the optical sensors used in the monitors vary with aerosol properties [34][35][36][37][38][39] and adjustment factors specific to wildfire smoke are needed.…”

The use of personal and indoor air pollution monitors in reproductive epidemiology studies

“…Unlike more expensive monitors with comprehensive regulatory standards and processes for evaluation and certification, few standards and no certifications exist for low‐cost air pollution monitors . There is a rapidly growing body of literature (and government agency guidance) on methods to calibrate and assess the performance of low‐cost sensors that is beyond the scope of this article to review . However, at a minimum, researchers should determine whether the instruments they are considering need to be calibrated against more traditional measures of the exposure of interest (and at what frequency), whether there is information regarding the performance of the sensor in environments similar to those proposed, and whether collection of other information (eg temperature and relative humidity, filter‐based particle measures) is needed to calibrate the sensor readings, and perform colocation of all instruments at set intervals to determine whether individual units require calibration or replacement.…”

“…To try and address many of these issues, low‐cost personal air pollution monitors are becoming increasingly common and represent an emerging potential tool to enhance personal exposure assessments in research studies, as long as they can be appropriately calibrated . Many of these monitors also have the capacity to link with a person's smartphone, further enhancing data collection possibilities including GPS tracking and momentary ecological assessment.…”

Investigating measurements of fine particle ( PM 2.5 ) emissions from the cooking of meals and mitigating exposure using a cooker hood

“…The correction is made by multiplying a measured concentration by a calibration factor . Additionally, the OPC may also under‐estimate the concentrations if a significant proportion of the emitted particles are smaller than the lower detection limit of the device . Accordingly, concurrent gravimetric sampling (GS) was used to determine the true mass concentrations using filter‐based GS devices for each test meal.…”