Assessment of PM_2.5 Exposure during Cycle Trips in The Netherlands Using Low-Cost Sensors

Air pollution, especially fine particulate matter (PM_2.5), is a major environmental risk factor for human health in Europe. Monitoring of air quality takes place using expensive reference stations. Low-cost sensors are a promising addition to this official monitoring network as they add spatial and temporal resolution at low cost. Moreover, low-cost sensors might allow for better characterization of personal exposure to PM_2.5. In this study, we use 500 dust (PM_2.5) sensors mounted on bicycles to estimate typical PM_2.5 levels to which cyclists are exposed in the province of Utrecht, the Netherlands, in the year 2020. We use co-located sensors at reference stations to calibrate and validate the mobile sensor data. We estimate that the average exposure to traffic related PM₂._5, on top of background concentrations, is approximately 2 μg/m³. Our results suggest that cyclists close to major roads have a small, but consistently higher exposure to PM_2.5 compared to routes with less traffic. The results allow for a detailed spatial representation of PM_2.5 concentrations and show that choosing a different cycle route might lead to a lower exposure to PM_2.5. Finally, we conclude that the use of mobile, low-cost sensors is a promising method to estimate exposure to air pollution.