Evaluation of Low-Cost Optical Particle Counters for Agricultural Exposure Measurements

Abstract

HighlightsThe OPC-N3, developed by Alphasense, may be useful in measuring occupational exposure in agricultural settings based on the agreement with mass concentrations measured by gravimetrical filter analysis.The AirBeam2 is better suited for environmental exposure measurements rather than occupational measurements.Particle sizing by the GRIMM Mini-WRAS 1371 and the OPC-N3 show many aerosols that agricultural workers are exposed to follow a bimodal curve and are above 0.1 µm, thereby the respirator used as personal protective equipment is effective in filtering out aerosols in this occupation.Abstract. Prolonged exposure to dust has been shown to have adverse health effects in agricultural workers, primarily with the development of respiratory diseases. Low-cost sensors may be cost-effective tools for farmers to determine when they are exposed to harmful levels of dust during their workday. The purpose of this study was to identify low-cost sensors that may be reliably used in occupational settings to help workers and employers identify respirable particle matter exposure. The study utilized two different low-cost optical particle counters (OPCs) to collect data on dust exposure, which were worn on a belt by the participant: the OPC-N3 developed by Alphasense and the AirBeam2 developed by HabitatMap. Additionally, an AirChek TOUCH air sampling pump fit with a respirable dust aluminum cyclone allowed for the collection of respirable particulate matter (PM4) to determine the true concentration of exposure. Results show that the PM4 measurements made by the OPC-N3 are similar to the gravimetrical filter measurement at concentrations of < 50 µg/m3. In addition, the data analysis suggests that the AirBeam2 may be significantly underestimating the amount of particulate matter that farmworkers are exposed to and therefore may not be suitable for occupational exposure measurements compared to the OPC-N3. Keywords: Aerosols, Agriculture, AirBeam2, Dust, Exposure, Low-cost, Occupational, Optical particle counter, OPC-N3.