The main aim of this study is the identification of the most appropriate measures and policies to combat particulate air pollution in the city of Thessaloniki, Greece through a methodology including the calculation of emissions by sector and the application of an air quality modeling system. The identification of the current air quality situation showed that the exceedances of the mean PM₁₀ daily levels occur during the cold winter months with residential heating being the major contributor representing a 73% share of total PM₁₀ emissions. Moreover, the effect of the biomass consumption for heating purposes on PM₁₀ concentrations has been verified and quantified by implementing a regression model identifying that a PM₁₀ emissions reduction by 45% would result in the elimination of the exceedances of the mean PM₁₀ daily values. Based on the above, a set of cost-effective measures and policies were defined and their impact on PM₁₀ emissions was estimated. Finally, the air quality modeling system was applied for the mitigation scenarios selected, leading to a significant reduction of 67% in the number of exceedances observed and ensuring compliance with the limit of 35 exceedances of the daily value limit per year pursuant to European Legislation.

In the present paper, we develop a non-homogeneous semi-Markov reward model, deriving expressions for a healthcare system’s expected structure along with the expected costs generated by medical services and patients’ holding times in the states. We provide a novel definition and investigation for states’ availability, which is critical for capacity planning based on service demand in an environment of limited resources. The study is based on patients’ mobility through hospital care, where each patient spends an amount of time in every state of the hospital (emergency room, short-term acute care, hospitalization, surgery room, and intensive care unit). Multiple outcomes, such as discharge or death, can also be taken into account. We envisage a situation where any discharges are immediately replaced by a number of new admissions that carry on the pathways of the patients who exit. By assuming an expanding system, the new idea of states’ inflows is considered due to new patients who create pathways through hospital care, along with internal entrances. The theoretical results are illustrated numerically with simulated hospital data informed by aggregated public data of the Greek public health sector. The framework can be used for both strategic planning and cost evaluation purposes for hospital resources.