Association between moderated level of air pollution and fetal growth: the potential role of noise exposure.

This study aims to analyze, in a population of singletons, the potential confounding or modifying effect of noise on the relationship between fetal growth restriction (FGR) or small for gestational age (SGA) and environmental exposure to air pollution. All women with single pregnancies living in one of two medium-sized cities (Besançon, Dijon) and who delivered at a university hospital between 2005 and 2009 were included. FGR and SGA were obtained from medical records. Outdoor residential exposure to nitrogen dioxide (NO2) and particulate matter (PM10) was quantified at the mother's address at delivery over defined pregnancy periods; outdoor noise exposure was considered to be the annual average daily noise levels in the façade of building (LAeq,24 h). Adjusted odds ratios (ORa) were estimated by multivariable logistic regressions. Among the 8994 included pregnancies, 587 presented FGR and 918 presented SGA. In the two-exposure models, for SGA, the ORa for a 10-µg/m3 increase of PM10 during the two last months before delivery was 1.18, 95%CI 1.00-1.41 and for FGR, these ORa were for the first and the third trimesters, and the two last months before delivery: 0.77 (0.61-0.97), 1.38 (1.12-1.70), and 1.35 (1.11-1.66), respectively. Noise was not associated with SGA or FGR and did not confound the relationship between air pollution and SGA or FGR. These results are in favor of an association between PM10 exposure and fetal growth, independent of noise, particularly towards the end of pregnancy, and of a lack of association between noise and fetal growth.

[Can trees and forests help in improving environmental noise quality?] / Les arbres et les forêts peuvent-ils contribuer à l'amélioration de l'environnement sonore ?

In this article, we focus on ground transportation noise abatement and more precisely road traffic noise control. From literature as well as our own experience in this field we aim at determining in which planting schemes are trees or forest strips beneficial to environmental noise abatement, for which expected noise attenuation and with which good practices.We start by a brief point on French regulation on road noise management and we present a synthetic review of main attenuation processes observed when sounds propagates through areas with trees: ground, diffusion and refraction effects. Then we consider some typical landscape configurations studied in the scientific literature and we provide with expected acoustic impact: a forest strip along a road infrastructure, a row of trees along a noise protection and trees in the city. We finally give a set of recommendations of correct use of trees and forest strips as an element to the improvement of outdoor sound environment. Our advice is to plant broadleaved evergreens or a mixture of broadleaved evergreens and coniferous, with a minimum density of 0.25 tree/m2. We also advise to cultivate the ground before trees planting and to use well-rotted organic matter. On the other hand we do not recommend planting trees at the top of earth berms.

Multiple pregnancies and air pollution in moderately polluted cities: Is there an association between air pollution and fetal growth?

BACKGROUND: Multiple pregnancies (where more than one fetus develops simultaneously in the womb) are systematically excluded from studies of the impact of air pollution on pregnancy outcomes. This study aims to analyze, in a population of multiple pregnancies, the relationship between fetal growth restriction (FGR), small for gestational age (SGA) and exposure to air pollution in moderately polluted cities. METHODS: All women with multiple pregnancies living in the city of Besançon or in the urban area of Dijon and who delivered at a university hospital between 2005 and 2009 were included. FGR and SGA were obtained from medical records. Outdoor residential nitrogen dioxide (NO2) exposure was assessed using the mother's address, considering a 50 m radius buffer over the following defined pregnancy periods: each trimester, entire pregnancy and two months before delivery. Logistic regression analyses were performed. RESULTS: This study included 249 multiple pregnancies with 506 newborns. The median of NO2 concentration considering a 50 m radius buffer during entire pregnancy was 23.1 µg/m3 (minimum at 10.1 µg/m3 and maximum at 46.7 µg/m3). No association was observed between NO2 and SGA whatever the pregnancy period (the odds ratio (OR) range 0.78 to 0.88). Regarding FGR, the OR associated with an increase of 10 µg/m3 of NO2 exposure during entire pregnancy was 1.52 (95% Confidence Interval (CI): 1.02-2.26). Similar results were observed for NO2 exposure during the various pregnancy periods. CONCLUSIONS: These results are in line with an association between NO2 and fetal growth in multiple pregnancies for an exposure mostly below the threshold set out in European legislation.

Does low to moderate environmental exposure to noise and air pollution influence preterm delivery in medium-sized cities?

Background: Preterm birth (PB) is an important predictor of childhood morbidity and educational performance. Beyond the known risk factors, environmental factors, such as air pollution and noise, have been implicated in PB. In urban areas, these pollutants coexist. Very few studies have examined the effects of multi-exposure on the pregnancy duration. The objective of this study was to analyse the relationship between PB and environmental chronic multi-exposure to noise and air pollution in medium-sized cities. Methods: A case-control study was conducted among women living in the city of Besançon (121 671 inhabitants) or in the urban unit of Dijon (243 936 inhabitants) and who delivered in a university hospital between 2005 and 2009. Only singleton pregnancies without associated pathologies were considered. Four controls were matched to each case in terms of the mother's age and delivery location. Residential noise and nitrogen dioxide (NO2) exposures were calculated at the mother's address. Conditional logistic regression models were applied, and sensitivity analyses were performed. Results: This study included 302 cases and 1204 controls. The correlation between noise and NO2 indices ranged from 0.41 to 0.59. No significant differences were found in pollutant exposure levels between cases and controls. The adjusted odds ratios ranged between 0.96 and 1.08. Sensitivity analysis conducted using different temporal and spatial exposure windows demonstrated the same results. Conclusions: The results are in favour of a lack of connection between preterm delivery and multi-exposure to noise and air pollution in medium-sized cities for pregnant women without underlying disease.

Noise Annoyance in Urban Children: A Cross-Sectional Population-Based Study.

Acoustical and non-acoustical factors influencing noise annoyance in adults have been well-documented in recent years; however, similar knowledge is lacking in children. The aim of this study was to quantify the annoyance caused by chronic ambient noise at home in children and to assess the relationship between these children's noise annoyance level and individual and contextual factors in the surrounding urban area. A cross sectional population-based study was conducted including 517 children attending primary school in a European city. Noise annoyance was measured using a self-report questionnaire adapted for children. Six noise exposure level indicators were built at different locations at increasing distances from the child's bedroom window using a validated strategic noise map. Multilevel logistic models were constructed to investigate factors associated with noise annoyance in children. Noise indicators in front of the child's bedroom (p ≤ 0.01), family residential satisfaction (p ≤ 0.03) and socioeconomic characteristics of the individuals and their neighbourhood (p ≤ 0.05) remained associated with child annoyance. These findings illustrate the complex relationships between our environment, how we may perceive it, social factors and health. Better understanding of these relationships will undoubtedly allow us to more effectively quantify the actual effect of noise on human health.

Association between ambient noise exposure and school performance of children living in an urban area: a cross-sectional population-based study.

Most of the studies investigating the effects of the external noise on children's school performance have concerned pupils in schools exposed to high levels due to aircraft or freeway traffic noise. However, little is known about the consequences of the chronic ambient noise exposure at a level commonly encountered in residential urban areas. This study aimed to assess the relationship between the school performance of 8- to 9-year-old-children living in an urban environment and their chronic ambient noise exposure at home and at school. The children's school performances on the national standardized assessment test in French and mathematics were compared with the environmental noise levels. Children's exposure to ambient noise was calculated in front of their bedrooms (Lden) and schools (LAeq,day) using noise prediction modeling. Questionnaires were distributed to the families to collect potential confounding factors. Among the 746 respondent children, 586 were included in multilevel analyses. On average, the LAeq,day at school was 51.5 dB (SD= 4.5 dB; range = 38-58 dB) and the outdoor Lden at home was 56.4 dB (SD= 4.4 dB; range = 44-69 dB). LAeq,day at school was associated with impaired mathematics score (p = 0.02) or impaired French score (p = 0.01). For a + 10 dB gap, the French and mathematics scores were on average lower by about 5.5 points. Lden at home was significantly associated with impaired French performance when considered alone (p < 10(-3)) and was borderline significant when the combined home-school exposure was considered (p = 0.06). The magnitude of the observed effect on school performance may appear modest, but should be considered in light of the number of people who are potentially chronically exposed to similar environmental noise levels.

An exploratory spatial analysis to assess the relationship between deprivation, noise and infant mortality: an ecological study.

BACKGROUND: Few studies have explored how noise might contribute to social health inequalities, and even fewer have considered infant mortality or its risk factors as the health event of interest.In this paper, we investigate the impact of neighbourhood characteristics - both socio-economic status and ambient noise levels - on the spatial distribution of infant mortality in the Lyon metropolitan area, in France. METHODS: All infant deaths (n = 715) occurring between 2000 and 2009 were geocoded at census block level. Each census block was assigned multi-component socio-economic characteristics and Lden levels, which measure exposure to noise. Using a spatial-scan statistic, we examined whether there were significant clusters of high risk of infant mortality according to neighbourhood characteristics. RESULTS: Our results highlight the fact that infant mortality is non-randomly distributed spatially, with clusters of high risk in the south-east of the Lyon metropolitan area (RR = 1.44; p = 0.09). After adjustments for socio-economic characteristics and noise levels, this cluster disappears or shifts according to in line with different scenarios, suggesting that noise and socio-economic characteristics can partially explain the spatial distribution of infant mortality. CONCLUSION: Our findings show that noise does have an impact on the spatial distribution of mortality after adjustments for socio-economic characteristics. A link between noise and infant mortality seems plausible in view of the three hypothetical, non-exclusive, pathways we propose in our conceptual framework: (i) a psychological pathway, (ii) a physiological disruption process and (iii) an unhealthy behaviours pathway. The lack of studies makes it is difficult to compare our findings with others. They require further research for confirmation and interpretation.

Nonlinear parabolic equation model for finite-amplitude sound propagation over porous ground layers.

The nonlinear parabolic equation (NPE) is a time-domain method widely used in underwater sound propagation applications. It allows simulation of weakly nonlinear sound propagation within an inhomogeneous medium. So that this method can be used for outdoor sound propagation applications it must account for the effects of an absorbing ground surface. The NPE being formulated in the time domain, complex impedances cannot be used and, hence, the ground layer is included in the computational system with the help of a second NPE based on the Zwikker-Kosten model. A two-way coupling between these two layers (air and ground) is required for the whole system to behave correctly. Coupling equations are derived from linearized Euler's equations. In the frame of a parabolic model, this two-way coupling only involves spatial derivatives, making its numerical implementation straightforward. Several propagation examples, both linear or nonlinear, are then presented. The method is shown to give satisfactory results for a wide range of ground characteristics. Finally, the problem of including Forchheimer's nonlinearities in the two-way coupling is addressed and an approximate solution is proposed.