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This paper presents the outcomes from a workshop of the European Network on the Health and Environmental Impact of Nanomaterials (NanoImpactNet). During the workshop, 45 experts in the field of safety assessment of engineered nanomaterials addressed the need to systematically study sets of engineered nanomaterials with specific metrics to generate a data set which would allow the establishment of dose-response relations. The group concluded that international cooperation and worldwide standardization of terminology, reference materials and protocols are needed to make progress in establishing lists of essential metrics. High quality data necessitates the development of harmonized study approaches and adequate reporting of data. Priority metrics can only be based on well-characterized dose-response relations derived from the systematic study of the bio-kinetics and bio-interactions of nanomaterials at both organism and (sub)-cellular levels. In addition, increased effort is needed to develop and validate analytical methods to determine these metrics in a complex matrix.

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Quantum yields for the products CH3CHO, CO2 and CH3COOH in the 350 nm photodecomposition of pyruvic acid are 0.48 ± 0.01, 1.27 ± 0.18 and 0.14, respectively, as measured in air at atmospheric pressure. In the presence of NO2 the quantum yield for CH3CHO was reduced to 0.30 ± 0.04 and peroxyacetyl nitrate was formed with a quantum yield of 0.15 ± 0.02. This is taken to indicate the formation of acetyl radicals in one of the primary processes.

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ning 11 and The Weldox GroupWe investigated airborne and internal exposure to manganese (Mn) and iron (Fe) among welders. Personal sampling of welding fumes was carried out in 241 welders during a shift. Metals were determined by inductively coupled plasma mass spectrometry. Mn in blood (MnB) was analyzed by graphite furnace atom absorption spectrometry. Determinants of exposure levels were estimated with multiple regression models. Respirable Mn was measured with a median of 62 (inter-quartile range (IQR) 8.4 --320) mg/m 3 and correlated with Fe (r ¼ 0.92, 95% CI 0.90 --0.94). Inhalable Mn was measured with similar concentrations (IQR 10 --340 mg/m 3 ). About 70% of the variance of Mn and Fe could be explained, mainly by the welding process. Ventilation decreased exposure to Fe and Mn significantly. Median concentrations of MnB and serum ferritin (SF) were 10.30 mg/l (IQR 8.33 --13.15 mg/l) and 131 mg/l (IQR 76 --240 mg/l), respectively. Few welders were presented with low iron stores, and MnB and SF were not correlated (r ¼ 0.07, 95% CI À0.05 to 0.20). Regression models revealed a significant association of the parent metal with MnB and SF, but a low fraction of variance was explained by exposure-related factors. Mn is mainly respirable in welding fumes. Airborne Mn and Fe influenced MnB and SF, respectively, in welders. This indicates an effect on the biological regulation of both metals. Mn and Fe were strongly correlated, whereas MnB and SF were not, likely due to higher iron stores among welders.

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

The finding that catalytic converters enhance the N20 emissions from motor vehicles gave rise to the concern that they may represent a significant source of N20. Measurements of N20 and CO2 emissions of a fleet of about 40,000 cars were conducted in two roadway tunnels in Stockholm, Sweden, and Hamburg, Germany, to estimate N20 emissions under normal driving conditions. To avoid any risk of artifact N20 formation, samples were analyzed within 1 min after collection Median N20 to CO2 molar emission ratios of 1.4 x 10 -4 and 0.6 x 10 -4 were measured in Stockl•olm and Hamburg, respectively. The lower emission ratio in Hamburg may well reflect the smaller fraction of catalyst-equipped cars in Germany (22%) compared to the Swedish vehicle fleet (33%) as well as low N20 emissions from trucks which were not allowed in the Stockholm tunnel. From our measurements we derive a N20 to CO2 molar emission ratio from cars equipped with catalysts in the median to interquartile range of 3.8 +-2.2 x 10 -4, from which present worldwide N20 emissions from cars are estimated to be 0.38 + 0.22 Tg N20 (0.24 _+ 0.14 Tg N) per year, corresponding to 3-16% of the atmospheric growth of 4.7 _+ 0.9 Tg N20/yr (3.0 _+ 0.6 Tg N/yr). From the worldwide emission of 0.38 Tg N20 we derived an emission of about 170 mg N20/km for catalyst-equipped cars, significantly higher than those reported in earlier studies. If the entire present fleet of cars were to be equipped with current types of catalysts, the global N20 emission could double and reach 6-32% of the atmospheric growth rate. l. 18,527Automot. Eng., 1979. Greenhouse effects due to man-made perturbations of trace gases, Science, 194, 685-690, 1976. Weiss, R., The temporal and spatial distribution of tropospheric nitrous oxide,