Exposure to Ultrafine Particles and PM 2.5 in Different Micro-Environments

Acute exposure to particles in urban air has been found to be associated with adverse health effects. It has been suggested that the particle number concentration of ultrafine particles (<0.1 μm in diameter) may be more relevant to the observed health effects than the particle mass concentration. In this study, (ultrafine) particle numbers and PM 2.5 mass (<2.5 μm in diameter) concentrations were measured in different micro-environments and during different activities. There was a considerable variation of particle concentration depending on the location of the measurement and the nearby particle-generating activity. The highest concentrations of particle numbers were found to be due to traffic, but most importantly cooking. The highest concentration of PM 2.5 mass was due to passive cigarette smoke. These data will be used to develop a model to estimate personal exposure to particle numbers and PM 2.5 mass concentration.