a b s t r a c tIndoor/Outdoor (I/O) particulate mass concentration (PM 10 ) and number concentrations were measured online in modern office environments with mechanical ventilation. The measurement took place during June 2014 in a building, which, belongs to the Norwegian Institute for Air Research, in Norway. Particle number size distribution was measured with an SMPS (0.014e0.7 mm) and an APS (0.5e18 mm) instruments, whereas, mass concentration was measured with a Dust-Trak II photometer. Two offices were selected to examine the outdoor contribution of particles and the influence of indoor sources. One office was fully occupied during working hours and the second one unoccupied at all times. The results suggested that human presence during the working hours affected considerably indoor particles in the occupied office both in terms of number and mass concentration compared to the non-working hours conditions. In the absence of any significant indoor source generating new particles (hardcopy devices), the indoor environment was influenced mainly from the presence of people with resuspension activities being the most important source for particle sizes larger than 1 mm. Moreover, indoor particle number and mass concentration was influenced substantially from outdoor sources. Generally, both indoor number and mass concentrations showed temporal fluctuations similar to those observed outdoors, suggesting that particle penetration was significant in both offices. However, low I/O ratio (90 th percentile < 0.3 for both offices) indicated the efficient removal of particles from the air filtration system.

The objective of the current study was to estimate health risk indexes caused by the inhalation of particulate matter (PM) by adult males and children using data sampled in three European cities (Athens, Kuopio, Lisbon). Accordingly, the cancer risk (CR) and the hazard quotient (HQ) were estimated from particle-bound metal concentrations whilst the epidemiology-based excess risk (ER), the attributable fraction (AF), and the mortality cases were obtained due to exposure to PM10 and PM2.5. CR and HQ were estimated using two methodologies: the first methodology incorporated the particle-bound metal concentrations (As, Cd, Co, Cr, Mn, Ni, Pb) whereas the second methodology used the deposited dose rate of particle-bound metals in the respiratory tract. The indoor concentration accounts for 70% infiltration from outdoor air for the time activity periods allocated to indoor environments. HQ was lower than 1 and the cumulative CR was lower than the acceptable level (10−4), although individual CR for some metals exceeded the acceptable limit (10−6). In a lifetime the estimated number of attributable cancer cases was 74, 0.107, and 217 in Athens, Kuopio, and Lisbon, respectively. Excess risk-based mortality estimates (due to outdoor pollution) for fine particles were 3930, 44.1, and 2820 attributable deaths in Athens, Kuopio, and Lisbon, respectively.

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The present study focused on the estimation of the personal dose of airborne particles using an exposure dose model (ExDoM2). Input data from three European cities (Athens, Kuopio, Lisbon) were selected to implement the model that calculates the deposited dose and retention of particles in the respiratory tract, the mass transferred to the oesophagus and the absorption to blood as well as the dose for five particle-bound metals. Model results showed that after one day exposure higher deposited dose in the respiratory tract was obtained for Lisbon as a direct consequence of the higher PM concentration measured in this city. Moreover, the activity profile and the physical characteristics of the exposed subject had strong impact on the estimated deposited dose. Thus, light activity corresponded to higher deposited dose compared to no activity as well as an adult male exhibited higher dose, both findings associated with increased inhalation rate. Regarding the internal dose for particle-bound metals higher dose for four out of the five metals was obtained in lungs followed by the muscles for As, the gastrointestinal tract for Cr, the other tissues for Mn, the intestines for Cd and finally for Pb higher dose was found in bones and blood.