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 PM_2.5. 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.

Forest fires are a major contributor of atmospheric gaseous and particulate pollutants. With respect to forest fires, Greece faces one of Europe’s most severe problems during summer. To create a forest fire emissions inventory, a database which holds data for forest fires in Greece during the period 1997–2003 was established in this study and a methodology for the quantification of both gaseous and particulate matter emissions from forest fires was developed. The contribution of forest fire pollutant emissions to the total anthropogenic and natural emissions in Greece has been estimated in detail for a specific period during July 2000 when widespread forest fires occurred in the Greek mainland. The mesoscale air quality modeling system UAM-AERO was used to quantify the contribution of forest fire emissions to the air pollution levels in Greece, and it was calculated that the forest fire emissions were the largest contributors to the air pollution problem in regions tens of kilometers away from the fire source during this period. The wildfire emissions were calculated to cause an increase in the average PM₁₀ concentration, organic aerosol mass, and gaseous concentration of several pollutants, among them CO, NO _x , and NH₃. An average contribution of 50% to the PM₁₀ concentration over the region around the burnt area and downwind of the fire source (approximately 500 km) is calculated with a maximum of 80%, whereas, for CO, the average contribution was 50% during this period. The theoretical calculations were compared with in situ observations of smoke aerosols captured by a backscatter lidar system over the Greater Athens Basin as well as with surface observations of NO₂ and O₃ and the calculated concentrations were in better agreement with observations when forest fire emissions were included in the model calculations.

Dosimetry models for the estimation of particle deposition in the human respiratory tract (RT) in conjunction with clearance transport models are vital components to relate human exposure with internal dose in a quantitative manner. The current work highlights knowledge and modelling approaches on particle deposition and translocation in the human body in an effort to determine health risks in respect to different particle physicochemical properties and human physiology parameters. These include breathing conditions, variability of the geometry of the RT, chemical composition and size of deposits. Different dosimetry modelling approaches have been studied including empirical formulations, one-dimensional flow modelling and computational fluid dynamic methods (CFD). The importance of a realistic modelling of hygroscopicity has been also investigated. A better understanding of the relationship between health effects and inhaled particle dose may be elaborated using dosimetry and clearance modelling tools. A future required approach is to combine dosimetry models with physiologically based pharmacokinetic models (PBPK) to simulate the transport and cumulative dose of particle-bound chemical species in different organs and tissues of the human body.