Monitoring of long-term personal exposure to fine particulate matter (PM2.5)

Personal monitoring is of a demanding nature; thus, it is very difficult to obtain personal data for periods longer than a few days or a maximum of a few weeks. To fill this gap, we have performed a study in which personal exposure to particulate matter of aerodynamic diameter under 2.5 μm (PM_2.5) was monitored for almost 1 year. One healthy, adult, non-smoking, female student living in Prague (Czech Republic) was involved in the study. A battery-operated, fast-responding nephelometer was worn by the individual for a period of 10 months, recording PM_2.5 concentration every 5 min. A written time activity diary was used to record the experimental person's movement and the microenvironments visited. The dataset was divided into 12 different (seven indoor and four outdoor and transit) microenvironments. The overall average of the year-long measurement was 14.9 ± 52.5 μg.m⁻³ (median, 8.0 μg.m⁻³). The highest PM_2.5 average concentration was detected in restaurant microenvironments (294.4 μg.m⁻³), while the second highest concentration was recorded in an indoor microenvironment heated by wood and coal stoves (112.2 μg.m⁻³). The lowest mean aerosol concentrations were detected outdoors in a rural/natural environment (7.0 μg.m⁻³) and indoors at the monitored person's home (9.3 μg.m⁻³). During the measurement period, isolated and brief, but very high concentration excursions over 500 μg.m⁻³ or even over 1,000 μg.m⁻³ were recorded. However, they accounted for less than 0.5% of the total time of personal exposure. We conclude that continuous long-term monitoring is a good tool capable of disclosing the frequency and severity of short-term peak events of high particulate concentrations, which may be associated with adverse health effects.