Journal of Health and Safety at Work

Introduction: Nowadays, Shielded Metal Arc Welding (SMAW) is the most widely used arc welding. During the welding operation, typically, various harmful agents such as fumes, gases, heat, sound and ultraviolet radiation are produced of which fume is the most important component from the viewpoint of occupational health. The present study aims to compare the number and the mass concentration emitted in SMAW to determine the most appropriate index of exposure to fumes in the welding processes.

Material and Method: In this study, the portable laser aerosol spectrometer and dust monitor of GRIMM, model 1.106, was used to measure the number and mass concentration of fumes emitted from SMAW on 304 stainless steel with a thickness of 0.4 mm. Air sampling was performed at a distance of 41 cm representing the welder’s breathing zone. The measurements of number concentration (NC) and mass concentration (MC) were taken under the condition of 25 volt voltage and direct current of the electrode polarity.

Result: The total NC and MC of welding fumes in welder’s breathing zone was 1140451 particles per liter and 1631.11 micrograms per cubic meter, respectively. The highest number concentration was found to correspond to the particles with 0.35 to 0.5 micrometer-sized distribution (NC1; 938976 particles per liter) and the lowest was related to the particles with 5 to 6.5 micrometer-sized distribution (NC7; 288 particles per liter) and the particles larger than 6.5 micrometer (NC8; 463 particles per liter). Moreover, the highest mass concentration was related to the particles with 0.35 to 0.5 micrometer-sized distribution (MC1; 450 micrograms per cubic meter) and the particles larger than 6.5 micrometer (MC8; 355 micrograms per cubic meter).

Conclusion: The findings indicated that there is no agreement between number and mass concentration as two particles assessment index, and as the particles’ size become smaller, the mismatch of them is becoming more apparent. Since the smaller particles penetrate into the lower respiratory tract and have higher potential for adverse health effects, it is necessary to measure and assess particles in various size distributions and especially the smaller fraction of particles. Therefore, it is thought that considering the mass concentration alone and not paying attention to number concentration in the assessment of exposure to particles in the industrial workplaces and specifically in welding stations will not be reflected valid assessment of adverse health effects of welding fumes as a systemic poison on body organs.

Introduction: Microorganisms in hospitals are potential sources of infection to patients and staffs. Bioaerosol exposure is associated with a vast range of adverse health effects including infectious diseases, acute toxic effects, allergy. This study aimed to survey the type and density of bioaerosols in ambient air of different wards of educational hospitals Ardabil in 2016.  
 

Material and Method: This cross-sectional study was conducted in 2 educational hospitals of Ardabil city in 2016. ZTHV02 sampler and Tryptic soy Agar along with Cycloheximide antibiotic were used to evaluate and determine the airborne bacterial counts. The average sampling time was 10 minutes. Air samples were transported to the lab just after sampling and incubated for 48 hours at 37 ºC. Then, raised colonies  were counted. Bacterial density was expressed as CFU/m3 ± SD.   
 

Result: Mean bacterial concentrations were 10.3 and 23.4 CFU/m3 in Imam and Alavi hospitals, respectively. X-ray room in Imam Khomeini hospital and ICU room in Alavi hospital had the highest bacterial count. But, the least bacterial loads were observed in ICU and Angiography wards of Imam Khomeini and CTSCAN ward in Alavi hospitals. The most prevalent bacteria species isolated from air samples of Imam hospital was Enterococcus spp followed by Pseudomonas spp, coagulase negative Staphylococci spp and Non -Enterococcus group D Streptococci and for Alavi hospital; Coagulase negative Staphylococci spp followed by Psodomonas spp, Klebsilla spp and, Enterococcus spp.
No significant correlations were found between bacterial counts, temperature and humidity of the sampling sites. However, bacteria density significantly were higher in morning shift comparing to evening shift (P <0.05).
 

Conclusion: High concentration of airborne bacteria bio-aerosols in Ardabil hospitals can be important health risks for health workers and the patients.