Occurrence and diurnal variation of polychlorinated biphenyls and polybrominated diphenyl ethers in the background atmosphere of Eastern Mediterranean.

During a two-week intensive field campaign conducted at a background location of the Eastern Mediterranean, consecutive 10-h air samples were collected under intense photochemical conditions and analyzed for polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). The average gas-phase concentration of total PCBs and PBDEs was 73+/-29 and 3.9+/-2.1 pg m(-3), respectively. The study of Clausius-Clapeyron plots and air mass back-trajectories assigned the origin of air masses as the factor largely controlling the variation of PCB and PBDE air concentrations in the study area. Using principal component analysis, discrete differences in PCBs homologue profiles were revealed between day and night samples and attributed to the daytime reaction with hydroxyl radicals. In contrast, PBDE homologue profiles did not show any characteristic day-to-night shifts that could be attributed to hydroxyl radical reaction or photolysis

Functional characterization of the Tetranychus urticae CYP392A11, a cytochrome P450 that hydroxylates the METI acaricides cyenopyrafen and fenpyroximate

Cyenopyrafen is a Mitochondrial Electron Transport Inhibitor (METI) acaricide with a novel mode of action at complex II, which has been recently developed for the control of the spider mite Tetranychus urticae, a pest of eminent importance globally. However, some populations of T. urticae are cross-resistant to this molecule, and cyenopyrafen resistance can be readily selected in the lab. The cytochrome P450s genes CYP392A11 and CYP392A12 have been strongly associated with the phenotype. We expressed the CYP392A11 and the CYP392A12 genes with T. urticae cytochrome P450 reductase (CPR) in Escherichia coli. CYP392A12 was expressed predominately as an inactive form, witnessed by a peak at P420, despite optimization efforts on expression conditions. However, expression of CYP392A11 produced a functional enzyme, with high activity and preference for the substrates Luciferin-ME EGE and ethoxycoumarin. CYP392A11 catalyses the conversion of cyenopyrafen to a hydroxylated analogue (kcat = 2.37 pmol/min/pmol P450), as well as the hydroxylation of fenpyroximate (kcat = 1.85 pmol/min/pmol P450). In addition, transgenic expression of CYP392A11 in Drosophila melanogaster, in conjunction with TuCPR, confers significant levels of fenpyroximate resistance. The overexpression of CYP392A11 in multi-resistant T. urticae strains, not previously exposed to cyenopyrafen, which had been indicated by microarray studies, was confirmed by qPCR, and it was correlated with significant levels of cyenopyrafen and fenpyroximate cross-resistance. The implications of our findings for insecticide resistance management strategies are discussed

Overview of the field measurement campaign in Hyytiälä, August 2001 in the framework of the EU project OSOA

As part of the OSOA (Origin and formation of Secondary Organic Aerosols) project, two intensive field campaigns were conducted in Melpitz, Germany and Hyytiälä, Finland. This paper gives an overview of the measurements made during the Hyytiälä campaign, which was held between 1 and 16 August 2001. Various instrumental techniques were used to achieve physical and chemical characterisation of a erosols and to investigate possible precursor gases. During the OSOA campaign in Hyytiälä, particle formation was observed on three consecutive days at the beginning of the campaign (1 to 3 August 2001) and on three days later on. The investigation of the meteorological situation divided the campaign into two parts. During the first three days of August, relatively cold and clean air masses from northwest passed over the station (condensation sink-CS: <0.002s-1, NOx: <0.5 ppb). Daily particle burst of one fraction of the nucleation mode aerosols (3-10 nm) with number concentrations between 600-1200 particles cm-3 were observed. After this period, warmer and more polluted air from south-west to south-east arrived at the station (CS: 0.002-0.01 s-1, NOx: 0.5-4 ppb) and during these 13 days only three events were observed. These events were not as apparent as those that occurred during the earlier period of the campaign. The chemical analyses from different institutes of PM2, PM2.5 and PM10 particles confirmed the assumption that organic mater from the oxidation of various terpenes contributed to the formation of secondary organic aerosols (SOA). Concerning these conclusions among others, the ratio between formic (oxidation product of isoprene and monoterpenes by ozone) and acetic acid (increased by anthropogenic emissions) (ratio=1 to 1.5) and concentration of different carboxylic acids (up to 62 ng m-3) were investigated. Gas/particle partitioning of five photo-oxidation products from α- and β-pinene resulted in higher concentrations of pinonic, nor pinonic and pinic acids in the particle phase than in the gas phase, which indicates a preference to the particle phase for these compounds. The average growth factors (GF) from 100 nm particles in water vapour gave a diurnal pattern with a maximum during daytime and values between 1.2 and 1.7. On average, the amount of secondary organic carbon reached values around 19% of the sampled aerosols and we speculate that formation of SOA with the influence of photo-oxidation products from terpenes was the reason for the observed particle bursts during the campaign. However, correlations between the precursor gases or the favourable condensing species with the monitored nucleation mode particles were not found. For the investigated time period other factors like the condensation sink of newly formed particles to the pre-existing aerosols, temperature and solar irradiance seem to be more important steering parameters for the production of new aerosols. Another open question concerns the vertical distribution of the formation of SOA. For this reason measurements were conducted at different altitudes using a tethered balloon platform with particle sampling and particle counting equipment. They were incorporated with eddy covariance (EC) flux measurements made at 23 m above ground level. The results give first indications that production of new aerosols happens throughout the planetary boundary layer (PBL), whereby different parameters e.g. temperature, CS, solar irradiance or concentration of monoterpenes are responsible for the location of the vertical maximum. © European Geosciences Union 2004

Global air pollution crossroads over the Mediterranean.

The Mediterranean Intensive Oxidant Study, performed in the summer of 2001, uncovered air pollution layers from the surface to an altitude of 15 kilometers. In the boundary layer, air pollution standards are exceeded throughout the region, caused by West and East European pollution from the north. Aerosol particles also reduce solar radiation penetration to the surface, which can suppress precipitation. In the middle troposphere, Asian and to a lesser extent North American pollution is transported from the west. Additional Asian pollution from the east, transported from the monsoon in the upper troposphere, crosses the Mediterranean tropopause, which pollutes the lower stratosphere at middle latitudes

The urban exposome during pregnancy and its socioeconomic determinants

Background: The urban exposome is the set of environmental factors that are experienced in the outdoor urban environment and that may influence child development. Objective: The authors’ goal was to describe the urban exposome among European pregnant women and understand its socioeconomic determinants. Methods: Using geographic information systems, remote sensing and spatio-temporal modeling we estimated exposure during pregnancy to 28 environmental indicators in almost 30,000 women from six population-based birth cohorts, in nine urban areas from across Europe. Exposures included meteorological factors, air pollutants, traffic noise, traffic indicators, natural space, the built environment, public transport, facilities, and walkability. Socioeconomic position (SEP), assessed at both the area and individual level, was related to the exposome through an exposome-wide association study and principal component (PC) analysis. Results: Mean±standard deviation (SD) NO2 levels ranged from 13.6±5.1 μg/m3 (in Heraklion, Crete) to 43.2±11 μg/m3 (in Sabadell, Spain), mean±SD walkability score ranged from 0.22±0.04 (Kaunas, Lithuania) to 0.32±0.07 (Valencia, Spain) and mean±SD Normalized Difference Vegetation Index ranged from 0.21±0.05 in Heraklion to 0.51±0.1 in Oslo, Norway. Four PCs explained more than half of variation in the urban exposome. There was considerable heterogeneity in social patterning of the urban exposome across cities. For example, high-SEP (based on family education) women lived in greener, less noisy, and less polluted areas in Bradford, UK (0.39 higher PC1 score, 95% confidence interval (CI): 0.31, 0.47), but the reverse was observed in Oslo (−0.57 PC1 score, 95% CI: −0.73, −0.41). For most cities, effects were stronger when SEP was assessed at the area level: In Bradford, women living in high SEP areas had a 1.34 higher average PC1 score (95% CI: 1.21, 1.48). Conclusions: The urban exposome showed considerable variability across Europe. Pregnant women of low SEP were exposed to higher levels of environmental hazards in some cities, but not others, which may contribute to inequities in child health and development.The research leading to these results received funding from the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement no 308333 – the HELIX project

Variation of NO2 and NOx concentrations between and within 36 European study areas: Results from ESCAPE study

The ESCAPE study (European Study of Cohorts for Air Pollution Effects) investigates long-term effects of exposure to air pollution on human health in Europe. This paper documents the spatial variation of measured NO2 and NOx concentrations between and within 36 ESCAPE study areas across Europe. In all study areas NO2 and NOx were measured using standardized methods between October 2008 and April 2011. On average, 41 sites were selected per study area, including regional and urban background as well as street sites. The measurements were conducted in three different seasons, using Ogawa badges. Average concentrations for each site were calculated after adjustment for temporal variation using data obtained from a routine monitor background site. Substantial spatial variability was found in NO2 and NOx concentrations between and within study areas; 40% of the overall NO2 variance was attributable to the variability between study areas and 60% to variability within study areas. The corresponding values for NOx were 30% and 70%. The within-area spatial variability was mostly determined by differences between street and urban background concentrations. The street/urban background concentration ratio for NO2 varied between 1.09 and 3.16 across areas. The highest median concentrations were observed in Southern Europe, the lowest in Northern Europe. In conclusion, we found significant contrasts in annual average NO2 and NOx concentrations between and especially within 36 study areas across Europe. Epidemiological long-term studies should therefore consider different approaches for better characterization of the intra-urban contrasts, either by increasing of the number of monitors or by modelling