Background: Continuous monitoring of air quality is implemented by government institutions at fixed ambient sites. However, the correlation between fixed site measurements and exposure of individual persons to air contaminants is likely to be weak.
Materials and methods: We measured particulate matter both outdoors and indoors by following the spatial movement of individuals. Sixteen test persons took part and carried a measurement backpack for a 24-h period. The backpack was comprised of a Grimm Aerosol Spectrometer model 1.109, a GPS device, and a video camera for tracking of human behavior. The spectrometer provided information about particle numbers and mass in 32-size classes with a high temporal resolution of 6 s.
Results: The personal exposure of individuals during 24 h could significantly exceed the outdoor particulate matter (PM)(10) concentrations measured at the fixed sites. The average 24-h exposure of all test persons for PM(10) varied from 27 to 322 μg m(-3). Environmental tobacco smoke and cooking emissions were among the main indoor sources for PM. The amount of particulate matter a test person was exposed to was highly dependent on the spatial behavior and the surrounding microenvironment conditions.
Discussion: Large-scale experiments including personal measurements might help to improve modeling approaches to approximate the actual exposure on a statistically sound basis.