Personal exposure and internal dose to particulate matter in a Mediterranean coastal city

Abstract

The direct method of personal monitoring was selected with the aim to estimate the exposure and the subsequent dose of residents a coastal Mediterranean city (Chania Greece), to ambient particles. Eight subjects conducted daily real-time measurements, for 3 days each, with the use of an optical particle sizer. The subjects kept a diary of activities and of the microenvironments they visited. Additionally, a time resolution of 1 min was selected, in order to study the impact of various activities and indoor sources on human exposure and consequently on the human dose. The highest personal mean exposure in particle number concentration (PN_0.3-10) was 80 particles/cm³, with average daily exposure 50 ± 16 particles/cm³, while the highest particle mass (PM₁₀) daily exposure was 36.1 μg/m³ with average PM₁₀ exposure concentration 18.7 ± 8.07 μg/m³. The impact of various activities on the indoor concentrations was also studied, with cooking resulting in sharp elevations in particle concentration, while other household activities also impacted the particles levels. Additionally, the dosimetry model, ExDoM2, was used to calculate the deposition and dose for both PN_0.3-10 and PM₁₀. The retention of PM₁₀ in the respiratory tract, the mass transferred to the oesophagus, and their absorption to blood was also estimated. The model results indicated that the highest PM₁₀ dose occurred in the extrathoracic region (ET) of the respiratory tract (RT) and after the 3 days of exposure, the highest amount of particles was transferred to the oesophagus.