The aim of this research work was determination of humidity impact on yeast and moulds survival in fibrous filters. It was revealed that water content of about - 53-113% stimulated growth of fungi, especially in case of moulds. In stable filters humidity conditions (50% of weight), a number of fungi reached I 04 CFU/cm2 after 84 days, with the most intensive growth during first 7 days of the experiment. In the case of very low humidity ( 13% and less), the growth of fungi was not observed.

Presented study aimed to determine metals distribution on the quartz fiber filters surface coated with particulate matter by using high and low-volume samplers. The distribution pattern was tested using two different sub-sampling schemes. Each sub-sample was mineralized in the nitric acid in a microwave oven. An analysis was performed by means of atomic absorption spectroscopy with electrothermal atomization GF-AAS technique, and the determined elements were: As, Cd, Pb and Ni. A validation of the analytical procedure was carried out using NIES 28 Urban Aerosols standard reference material.

It was assumed that metal is distributed uniformly if its normalized concentrations on a single sub-sample is within ±15% of the mean concentration over the whole filter. The normalized concentrations values exceed this range, indicating a non-homogenous metals distribution. There were no statistically significant differences in metals concentrations between particular sub-samples in the function of its position along the filters diameter.

Growing awareness for occupational safety in the welding environment needs a sustainable welding system. Welding gases releases toxic tiny particles and gases that inflict severe health consequences in the weld zone are unsolicited. Some of the other main adverse effects are lung disease, hemoptysis, pulmonary inflammation, pneumoconiosis, etc. GMAW procedure has been used for welding 316L stainless steel plates of 3 mm, 5 mm, and 6 mm. Various current configurations with gas flow rate of 5 LPM, 10 LPM and 15 LPM were also used to achieve optimum butt joint performance and to reduce the production rate of fume contributing to cost-effectiveness. In this research a cost-effective fume extraction hood was fabricated for measuring Emission factor produced during welding. Various shielding gas compositions including Pure Argon, Pure CO2, 92% Ar+8% CO2 and 88% Ar+12% CO2 were used to determine the best operating parameters in the GMAW method. To satisfy the latest Permissible Exposure Limit (PEL) legislation, optimum technical parameters for efficient welding were acknowledged with the lowest emission factor. A maximum reduction of Emission factor can be achieved by using Pure Argon. The inclusion of CO2 as a shielding gas mixture gives higher emission factor when compared to Pure Argon. Very low emission factor were witnessed in this research when compared to previous investigations. Lower emission factor of 2941.17 mg /kg of electrode, 4411.76 mg/kg of electrode and 7352.94 mg/kg of electrode were obtained for pure argon as shielding gas with 150 A welding current.