Exposure to PM_2.5 while walking in the city center

Physical activity, such as walking, plays a key role in preventing noncommunicable diseases. However, in urban environments, pedestrians are often exposed to elevated air pollution levels, especially fine particulate matter (PM_2.5), which poses significant health risks. This study investigates personal exposure to PM_2.5 while commuting on short walking routes in Gliwice, Poland, a city known for its high air pollution levels. It compares measurements made using a low-cost air quality sensor with data from stationary air quality monitoring stations and an air quality laboratory at the Silesian University of Technology (SUT). The aim of this study is to assess real-time PM_2.5 exposure and address data gaps for health risk assessments. This study was conducted between January and November 2022, focusing on the participants' daily walking routines to the university campus. Data analysis included pollutant concentrations, environmental conditions, and statistical comparisons between different seasons (heating and non-heating). The results indicated that PM_2.5 levels measured by the low-cost sensor were lower than those recorded at the stationary sites, with average concentrations of 7.3 µg/m³ during both seasons. The stationary data from the monitoring station and the SUT laboratory reported higher average concentrations of 12.3 and 20.1 µg/m³, as well as 16.0 and 29.1 µg/m³, during the non-heating and heating season, respectively, showing statistically significant seasonal variations, unlike the low-cost sensor. The results suggest that low-cost sensors, while useful for real-time individual exposure monitoring, may lack the sensitivity needed to detect seasonal variations compared to reference-grade instruments. Overall, this study emphasizes the importance of appropriate measurement methods for assessing air quality and highlights the potential role of low-cost sensors in personal exposure tracking, raising awareness about air pollution.