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Abstract: In many built-up urban areas, tall buildings along narrow streets obstruct the free flow of air, resulting in higher pollution levels. Input data to account for street configuration in models are difficult to obtain for large numbers of streets. We describe an approach to calculate indicators of this “urban canyon effect” using 3-dimensional building data and evaluated whether these indicators improved spatially resolved land use regression (LUR) models. Concentrations of NO2 and NO x were available from 132 sites in the Netherlands. We calculated four indicators for canyon effects at each site: (1) the maximum aspect ratio (building height/width of the street) between buildings on opposite sides of the street, (2) the mean building angle, which is the angle between the horizontal street level and the line of sight to the top of surrounding buildings, (3) median building angle and (4) “SkyView Factor” (SVF), a measure of the total fraction of visible sky. Basic LUR models were computed for both pollutants using common predictors such as household density, land-use and nearby traffic intensity. We added each of the four canyon indicators to the basic LUR models and evaluated whether they improved the model. The calculated aspect ratio agreed well (R 2 = 0.49) with aspect ratios calculated from field observations. Explained variance (R 2) of the basic LUR models without canyon indicators was 80% for NO2 and 76% for NO x , and increased to 82% and 78% respectively if SVF was included. Despite this small increase in R 2, contrasts in SVF (10th–90th percentile) resulted in substantial concentration differences of 5.56 μg m−3 in NO2 and 10.9 μg m−3 in NO x . We demonstrated a GIS based approach to quantify the obstruction of free air flow by buildings, applicable for large numbers of streets. Canyon indicators could be valuable to consider in air pollution models, especially in areas with low- and high-rise canyons. [Copyright &y& Elsevier]

Background: Little is known about the exposure of young children to radiofrequency electromagnetic fields (RF-EMF) and potentially associated health effects. We assessed the relationship of RF-EMF exposure from different sources and screen time exposure with emotional and behavioural problems in 5-year-old children.Methods: Cross-sectional study including 3102 children aged 5 years from the Amsterdam Born Children and their Development (ABCD) study, in the Netherlands. Residential RF-EMF exposure from mobile phone base stations was estimated with a 3D geospatial radio wave propagation model. Residential presence of RF-EMF indoor sources (cordless phone base stations and Wireless Fidelity (WiFi)), children's mobile phone and cordless phone calls and screen time exposure (computer/video game and television watching) was reported by the mother. Teachers (n = 2617) and mothers (n = 3019) independently reported child emotional and behavioural problems using the Strengths and Difficulties Questionnaire.Results: No associations were found between mobile phone and cordless phone calls and emotional and behavioural problems. Children exposed to higher RF-EMF levels from mobile phone base stations showed higher odds of maternal-reported emotional symptoms (OR 1.82, 95%CI 1.07 to 3.09). Children with cordless phone at home had lower odds of teacher-reported problematic prosocial behaviour (OR 0.68, 95%CI 0.48 to 0.97) and of maternal-reported peer relationship problems (OR 0.61, 95% CI 0.39 to 0.96). Children who watched television ≥1.5 h/day had higher odds of maternal-reported hyperactivity/inattention (OR 3.13, 95%CI 1.43 to 6.82).Conclusion: Mobile phone and cordless phone calls, which lead to peak RF-EMF exposures to the head, were not associated with any emotional and behavioural problems in 5-year-old children. Environmental RF-EMF exposure from mobile phone base stations and from indoor sources and television watching, which both contribute very little to RF-EMF exposure, were associated with specific emotional and behavioural problems but mainly when reported by the mothers. We cannot, however, discard residual confounding or reverse causality. Further longitudinal research in particular as children will increase the use of telecommunication devices with the age may help to better understand the exact contribution of the different RF-EMF exposure sources if any. Moreover, a thorough control for confounding is essential for a correct interpretation of the studies on screen time and emotional and behavioural problems. [ABSTRACT FROM AUTHOR]

Abstract: Background: Concerns of the general public about potential adverse health effects caused by radio-frequency electromagnetic fields (RF-EMFs) led authorities to introduce precautionary exposure limits, which vary considerably between regions. It may be speculated that precautionary limits affect the base station network in a manner that mean population exposure unintentionally increases. Aims: The objectives of this multicentre study were to compare mean exposure levels in outdoor areas across four different European cities and to compare with regulatory RF-EMF exposure levels in the corresponding areas. Methods: We performed measurements in the cities of Amsterdam (the Netherlands, regulatory limits for mobile phone base station frequency bands: 41–61V/m), Basel (Switzerland, 4–6V/m), Ghent (Belgium, 3–4.5V/m) and Brussels (Belgium, 2.9–4.3V/m) using a portable measurement device. Measurements were conducted in three different types of outdoor areas (central and non-central residential areas and downtown), between 2011 and 2012 at 12 different days. On each day, measurements were taken every 4s for approximately 15 to 30min per area. Measurements per urban environment were repeated 12 times during 1year. Results: Arithmetic mean values for mobile phone base station exposure ranged between 0.22V/m (Basel) and 0.41V/m (Amsterdam) in all outdoor areas combined. The 95th percentile for total RF-EMF exposure varied between 0.46V/m (Basel) and 0.82V/m (Amsterdam) and the 99th percentile between 0.81V/m (Basel) and 1.20V/m (Brussels). Conclusions: All exposure levels were far below international reference levels proposed by ICNIRP (International Commission on Non-Ionizing Radiation Protection). Our study did not find indications that lowering the regulatory limit results in higher mobile phone base station exposure levels. [Copyright &y& Elsevier]