PM2.5 and PM10 exposure assessment: a comparative analysis between personal monitoring and environmental data

The evaluation of personal exposure to PM is a critical component of risk assessment: one of the main challenges is represented by the difficulty in simultaneously obtaining extensive and accurate personal exposure data for large populations. This study provides an empirical comparison between personal PM2.5 and PM10 exposure measurements and routinely available ambient data from fixed monitoring stations and air quality models in a hybrid working scenario. Time-activity information was also explored to identify activity patterns descriptively associated with larger discrepancies between personal and ambient estimates. To achieve this goal, a complex scenario consisting of a working day from home and a working day from office was considered. Personal exposure data were compared with daily average ambient data retrieved for both the residential and workplace addresses of each subject, using three different approaches: (i) Address-Specific; (ii) Residential-Address; (iii) Workplace-Address. According to the results, ambient data may provide useful proxies for average exposures whereas their ability to represent individual exposure was limited. Exceptions were observed for PM2.5 ambient data from monitoring for the Address-Specific and Residential-Address references. The main discrepancies were observed at high personal exposure levels, where ambient data showed a strong tendency to underestimate. Finally, larger discrepancies were descriptively associated with selected activity patterns, including indoor free time away from home, personal care, and secondhand smoke exposure.