Application of low-cost, commercially available, wearable particulate matter sensors: a comparison

BACKGROUND AND AIM Low-cost, wearable PM sensors claim to measure air quality with high spatiotemporal resolution, potentially improving exposure assessment in studies on air pollution. Exposure during commutes or indoor/outdoor leisure activities is difficult to accurately estimate with models and activity diaries. Short-term fluctuations or peak concentrations could be more relevant than annual averages for some health endpoints. High resolution data from PM wearables can be linked to acute bodily responses, or for identification of high exposure activities and hotspots. Here, we investigated performance of different PM wearables. METHODS Five commercially available PM wearables were purchased in triplo: AirBeam2, Atmotube PRO, Plume Labs Flow 2, Wynd Air Quality Tracker and Nova Fitness SDL607. Devices were placed at two national air quality monitoring stations for several consecutive days (June/July 2020). Measurement intervals varied per wearable (1 sec. - 5 min). All provided PM2.5 data, which was the main interest as respirable fraction linked to several health effects. Agreement (spearman correlation) between and within wearables was investigated (5 min. averages), and with hourly reference data. RESULTS The AirBeam was omitted from analysis due to missing data. High agreement for PM2.5 was found within and between the Atmotube, Wynd and SDL607 wearables. Agreement with reference PM2.5 data was limited. Some short-term peaks did not appear in the (hourly) reference, but were consistently detected by several wearables. CONCLUSIONS Their absolute measurement value might not precise, but these PM wearables showed consistent and repeatable patterns, indicating that they can distinguish high vs. low exposure situations at a high temporal resolution. Missing data and connection problems and unknown internal calibration algorithms are issues for application. Based on several (user) parameters, the best performing wearable (Atmotube PRO) was further investigated and applied in volunteer experiments. KEYWORDS Air pollution; PM; wearable; sensor; exposure assessment.