Exposure to Inhalable, Respirable, and Ultrafine Particles in Welding Fume

This investigation aims to explore determinants of exposure to particle size-specific welding fume. Area sampling of ultrafine particles (UFP) was performed at 33 worksites in parallel with the collection of respirable particles. Personal sampling of respirable and inhalable particles was carried out in the breathing zone of 241 welders. Median mass concentrations were 2.48 mg m−3 for inhalable and 1.29 mg m−3 for respirable particles when excluding 26 users of powered air-purifying respirators (PAPRs). Mass concentrations were highest when flux-cored arc welding (FCAW) with gas was applied (median of inhalable particles: 11.6 mg m−3). Measurements of particles were frequently below the limit of detection (LOD), especially inside PAPRs or during tungsten inert gas welding (TIG). However, TIG generated a high number of small particles, including UFP. We imputed measurements <LOD from the regression equation with manganese to estimate determinants of the exposure to welding fume. Concentrations were mainly predicted by the welding process and were significantly higher when local exhaust ventilation (LEV) was inefficient or when welding was performed in confined spaces. Substitution of high-emission techniques like FCAW, efficient LEV, and using PAPRs where applicable can reduce exposure to welding fume. However, harmonizing the different exposure metrics for UFP (as particle counts) and for the respirable or inhalable fraction of the welding fume (expressed as their mass) remains challenging

Diesel Exhaust Exposure and the Risk of Lung Cancer—A Review of the Epidemiological Evidence

To critically evaluate the association between diesel exhaust (DE) exposure and the risk of lung cancer, we conducted a systematic review of published epidemiological evidences. To comprehensively identify original studies on the association between DE exposure and the risk of lung cancer, literature searches were performed in literature databases for the period between 1970 and 2013, including bibliographies and cross-referencing. In total, 42 cohort studies and 32 case-control studies were identified in which the association between DE exposures and lung cancer was examined. In general, previous studies suffer from a series of methodological limitations, including design, exposure assessment methods and statistical analysis used. A lack of objective exposure information appears to be the main problem in interpreting epidemiological evidence. To facilitate the interpretation and comparison of previous studies, a job-exposure matrix (JEM) of DE exposures was created based on around 4,000 historical industrial measurements. The values from the JEM were considered during interpretation and comparison of previous studies. Overall, neither cohort nor case-control studies indicate a clear exposure-response relationship between DE exposure and lung cancer. Epidemiological studies published to date do not allow a valid quantification of the association between DE and lung cancer

Method for the determination of quartz and cristobalite : Air Monitoring Methods, 2015

The analytical method is validated for the determination of quartz and cristobalite in workplace air averaged over the sampling period after personal or stationary sampling. Sampling is performed by drawing a defined volume of air through a membrane filter located in the sampling head of the sampling device using a suitable pump. The respirable dust fraction is collected during sampling as stipulated in EN 481. Examples of sampling systems that have proved successful are PM 4F, VC 25F, FSP‐10, FSP‐BIA, and MPG II. Gravimetric determination of the respirable dust fraction is initially carried out, and then the concentration of quartz and cristobalite are determined in the respirable dust fraction with the aid of Fourier Transform Infrared Spectroscopy (FTIR). The determination is based on the blank value method and the method of calibration function in the lower measurement range according to DIN 32645. For the used sampling system FSP‐10 respectively PM‐4F the limit of quantification (LOQ) is 0.025 respectively 0.004 mg/m3 for a sampling period of two hours (air sample volume 120 litres / 8 m3) and 0.006 respectively 0.001 mg/m3 for a sampling period of eight hours (air sample volume 480 litres / 32 m3)

Probenahme und Bestimmung von Aerosolen und deren Inhaltsstoffen – Bestimmung von metallhaltigen Staubinhaltsstoffen : Air monitoring methods in German language, 2019

In addition to the gravimetric determination of airborne particles (total concentration), it is often necessary to selectively determine metals and their compounds in particle fractions because of their toxicological relevance. Usually, the total metal concentration is determined independently of the type of binding or oxidation state in a sample. From an occupational medical and toxicological point of view it makes sense to distinguish between different compounds of a metal, because type and extent of the toxic effect of metals depend considerably on their binding type and their solubility in the human body. In addition to the limit values of the respirable and inhalable particle fraction that must be complied, many metals have an OEL (occupational exposure limit) or MAK value that has to be checked and complied too. For cancerogenic compounds the exposure‐risk relationship has to be considered. Analysis for metals and their compounds predominantly resorts to methods, which require that the dust particle sample is brought into solution. That means the metals and their compounds contained in the sample need to be extracted, dissolved or digested. Aim of the sample preparation is the complete solution of all relevant substances to be analysed. Common digestion methods are for example acid digestion, which uses an acid mixture to digest the sample, and the suspension method, in which acetone is used to suspend the sample. An alternative sample preparation method is the microwave‐assisted pressure digestion with acid/acid mixture. In this chapter the different digestion methods are presented, discussed and compared, taking into account recent developments, in particular microwave‐assisted digestion