The role of open-air inhalatoria in the air quality improvement in spa towns

Objectives: The present study was aimed at evaluating microbiological contamination of air in Ciechocinek and Ino­wro­cław – Polish lowland spa towns. Additionally, the impact of open-air inhalatoria on the quality of air was evaluated. Material and Methods: Air samples were collected seasonally in the urban areas, in the recreation areas and in the vicinity of inhalatoria in both towns using impaction. The numbers of mesophilic bacteria, staphylococci, hemolytic bacteria and actinomycetes were determined on media according to the Polish Standard PN-86/Z-04111/02. The number of moulds was determined on media according to the Polish Standard PN-86/Z-04111/03. Results: While the highest numbers of microorganisms were noted at the sites located in the urban areas, the lowest numbers were noted in the vicinity of the open-air inhalatoria. In all the investigated air samples the values of bioaerosol concentrations were below the recommended TLVs (≤ 5000 CFU×m–3 for both bacteria and fungi in outdoor environments). Location of the sampling site was invariably a decisive factor in determining the number of microorganisms in the air. Conclusions: The aerosol which is formed in the open-air inhalatoria has a positive influence on microbiological air quality. Owing to a unique microclimate and low air contamination, Ciechocinek and Inowrocław comply with all necessary requirements set for health resorts specializing in treating upper respiratory tract infections

Evaluation of roadway Gaussian plume models with large-scale measurement campaigns

Gaussian models are commonly used to simulate atmospheric pollutant dispersion near sources because they provide an efficient compromise between reasonable accuracy and manageable computational time. The Gaussian dispersion formula provides an exact solution to the atmospheric diffusion equation for the dispersion of a pollutant emitted from a point source. However, the Gaussian dispersion formula for a line source, which is convenient to model emissions from on-road traffic, is exact only when the wind is perpendicular to the line source. A novel approach that reduces the error in the line source formula when the wind direction is not perpendicular to the road was recently developed. This model is used to simulate NO_x concentrations in a large case study (1371 road sections representing about 831 km). NO₂, NO and O₃ concentrations are then computed using the photostationary-state approximation. NO₂ concentrations are compared with measurements made at 242 locations in the domain area. Model performance is satisfactory with mean normalised errors of 22% (winter month) to 31% (summer month). Results obtained here are also compared with those obtained with a previous formulation and with a standard model used for regulatory applications, ADMS-Urban. Discrepancies among the results obtained with those models are discussed

Time Resolved Photoluminescence Study of the Wide (Cd,Mn)Te/(Cd,Mg)Te Quantum Well

The static and dynamic properties of excitons and trions in a 80 nm wide $Cd_{1-x}Mn_xTe/Cd_{0.7}Mg_{0.3}$Te quantum well with extremely small Mn content (x=0.00027) have been studied by means of time-integrated and time-resolved photoluminescence experiment at low and elevated temperatures. The trion binding energy has been estimated to be 2.6 ± 0.8 meV. The exciton and trion lifetimes have been measured to be ≈ 150 ps, and ≈ 200 ps, respectively. The temperature dependence of both lifetimes together with the multicomponent character of the PL decay process suggest a spatial localization of excitons and trions in the investigated quantum well