Residential green is associated with reduced annoyance to road traffic and railway noise but increased annoyance to aircraft noise exposure

In recent years, residential green and availability of neighbourhood green spaces came into focus as a potential means to reduce transportation noise annoyance. Literature suggests that various characteristics of residential green may play a role, namely, greenness of the residential areas as quantified by the normalized difference vegetation index (NDVI), visible vegetation from home, and the presence of public green spaces as identified by land use classification data (LU-green), as well as their accessibility and noise pollution (i.e., transportation noise exposure within green areas, how loud/quiet they are). So far, studies mostly focused on road traffic noise in urban areas.; We investigated the effects of residential green on noise annoyance, accounting for different transportation noise sources as well as for the degree of urbanisation.; We complemented the data set of the recent Swiss SiRENE survey on road traffic, railway and aircraft noise annoyance with a wide range of "green" metrics, and investigated their association with annoyance by means of logistic regression analysis (generalized estimating equations).; Increasing residential green was found to be associated with reduced road traffic and railway noise annoyance, but increased aircraft noise annoyance. The overall effect corresponded to equivalent level reductions of about 6 dB for road traffic and 3 dB for railway noise, but to an increase of about 10 dB for aircraft noise, when residential green increased from "not much green" (5th percentile of the study sample distribution) to "a lot of green" (95th percentile). Overall, NDVI and LU-green were particularly strongly linked to annoyance. The effects of visible vegetation from home and accessibility and/or quietness of green spaces were, overall, less strong, but depended on the degree of urbanisation. For road traffic noise, visible vegetation and accessibility of green spaces seem to particularly strongly reduce annoyance in cities, while quiet green spaces are more effective in rural areas.; Our study emphasizes that residential green should be fostered by city planners, particularly in densely populated areas

Individual aircraft noise exposure assessment for a case-crossover study in Switzerland

Accurate exposure assessment is essential in environmental epidemiological studies. This is especially true for aircraft noise, which is characterized by a high spatial and temporal variation. We propose a method to assess individual aircraft noise exposure for a case-crossover study investigating the acute effects of aircraft noise on cardiovascular deaths. We identified all cases of cardiovascular death (24,886) occurring near Zürich airport, Switzerland, over fifteen years from the Swiss National Cohort. Outdoor noise exposure at the home address was calculated for the night preceding death and control nights using flight operations information from Zürich airport and noise footprints calculated for major aircraft types and air routes. We estimated three different noise metrics: mean sound pressure level (L; Aeq; ), maximum sound pressure level (L; Amax; ), and number above threshold 55 dB (NAT; 55; ) for different nighttime windows. Average nighttime aircraft noise levels were 45.2 dB, 64.6 dB, and 18.5 for L; Aeq; , L; Amax; , and NAT; 55; respectively. In this paper, we present a method to estimate individual aircraft noise exposure with high spatio-temporal resolution and a flexible choice of exposure events and metrics. This exposure assessment will be used in a case-crossover study investigating the acute effects of noise on health

Effects of alpine hydropower operations on primary production in a downstream lake

Abstract.: During the past century, the construction of hydropower dams in the watershed of Lake Brienz has significantly altered the dynamics of turbidity, which has important implications for lake productivity. To assess these effects, we measured in situ carbon assimilation rates and ambient light intensities over 18months. Based on experimental data, a numerical model was developed to assess gross primary production under present light conditions and those under a hypothetical case without upstream dams. Light conditions for the hypothetical ‘no-dam' situation were estimated from pre-dam Secchi depths and simulated ‘no-dam' particle concentrations. Current gross primary production is low (~66 gC m−2 yr−1), and could increase ~44% if the lake was less turbid. Disregarding nutrient retention in reservoirs, we estimate gross primary production would be ~35% lower in summer and ~23% higher in winter in the absence of reservoirs. The annual primary production (~58 gC m−2 yr−1) would decrease ~12% compared to the current primary production with dams. According to model calculations, hydropower operations have significantly altered the seasonal dynamics, but have little effect on annual primary production in Lake Brien

Evaluation of flyover auralisations of today's and future long-range aircraft concepts

The European research project ARTEM (Aircraft noise Reduction Technologies and related Environmental iMpact) develops innovative aircraft noise reduction technologies such as advanced engine fan lining, metamaterials and low-noise high-lift systems applied to a vehicle with enhanced shielding of the engine noise, namely, a blended wing body. Using aircraft flyover auralisation in laboratory listening experiments, such future technologies can be evaluated with respect to human sound perception. To assess the reliability of such perception-based evaluations, the simulation should be validated with existing aircraft flyovers. This contribution presents a systematic and rigorous hierarchical validation of auralisations of current jet aircraft using field recordings. Uncertainty in the source modelling is considered by using two different prediction tools for partial sound sources. In addition to comparing computed noise indicators, a psychoacoustic validation is done in laboratory listening experiments with a 3D loudspeaker array. The validation comprises three levels: direct comparison of auralisations with recordings to study the identifiability of auralisations, ranking of auralisations and recordings regarding plausibility, and subjective annoyance ratings to test whether auralisations and recordings differ with respect to noise effects. Further, first results on the comparison of a future concept with a current aircraft are presented

How Do Road Traffic Noise and Residential Greenness Correlate with Noise Annoyance and Long-Term Stress? Protocol and Pilot Study for a Large Field Survey with a Cross-Sectional Design

Urban areas are continuously growing, and densification is a frequent strategy to limit urban expansion. This generally entails a loss of green spaces (GSs) and an increase in noise pollution, which has negative effects on health. Within the research project RESTORE (Restorative potential of green spaces in noise-polluted environments), an extended cross-sectional field study in the city of Zurich, Switzerland, is conducted. The aim is to assess the relationship between noise annoyance and stress (self-perceived and physiological) as well as their association with road traffic noise and GSs. A representative stratified sample of participants from more than 5000 inhabitants will be contacted to complete an online survey. In addition to the self-reported stress identified by the questionnaire, hair cortisol and cortisone probes from a subsample of participants will be obtained to determine physiological stress. Participants are selected according to their dwelling location using a spatial analysis to determine exposure to different road traffic noise levels and access to GSs. Further, characteristics of individuals as well as acoustical and non-acoustical attributes of GSs are accounted for. This paper presents the study protocol and reports the first results of a pilot study to test the feasibility of the protocol

A comparative study of semi-empirical noise emission models based on the PANAM and sonAIR aircraft noise simulation tools

In the context of aircraft noise simulations, an accurate representation of the aircraft noise sources is crucial so that reliable predictions can be obtained. In this contribution, we present a comparative study between the predictions provided by the emission models based on the DLR’s in-house PANAM tool and the sonAIR simulation software. Both are based on semi-empirical descriptions of the engine and airframe noise contributions, meaning that the emission levels are modeled separately for each noise source according to the operational conditions of the aircraft. This allows the comparison of the emission models not only in terms of the aircraft’s overall noise levels, but also regarding its different noise sources. The comparative study considers models representing the noise emissions of an A319 aircraft, which are provided by both simulation tools but further simulated within the sonAIR software environment in order to yield noise immission levels on a large calculation area. In general, a good agreement is observed for the departure procedure due to the similar performance of the engine noise models. In contrast, larger differences are observed during the approach procedure and at larger distances from the runway, which might be explained by differences in the airframe noise models

Leq+X - Lärmexposition, Ereignishäufigkeiten und Belästigung:

In dieser Studie wird ein Teil der Datensätze von 4 großen Schweizer und deutschen Fluglärmwirkungsstudien mit Hilfe von logistischen Mehrebenenmodellen re-analysiert. Ziel ist die Untersuchung der Annahmen, dass die Vorhersage a) des Anteils durch Fluglärm hoch belästigter Personen und b) des Anteils durch Fluglärm hoch schlafgestörter Personen verbessert werden kann, wenn (i) statt des energieäquivalenten Dauerschallpegels alleine entweder zusätzliche oder alternative, stärker häufigkeitsbasierte Flugverkehrsgeräuschparameter und (ii) zusätzlich spezifische Flughafencharakteristika als Prädiktoren genutzt werden. Diese Annahmen werden durch die Ergebnisse unterstützt, sowohl bezogen auf den Anteil hoch belästigter Personen, als auch bezogen auf den Anteil hoch schlafgestörter Personen. In this study, part of the data sets from 4 large Swiss and German aircraft noise impact studies are re-analysed using logistic multi-level regression models. The aim is to investigate the assumptions that the prediction of a) the percentage of persons highly annoyed by aircraft noise or b) the percentage of persons highly sleep disturbed by aircraft noise can be improved if (i) instead of the energy-equivalent continuous noise level alone, either additional or alternative, more frequency-based aircraft noise metrics and (ii) also airport-specific characteristics are used as predictors. The results support both assumptions; both regarding the percentage of persons highly annoyed and regarding the percentage of persons highly sleep disturbed. Die Studie wurde von dem Bundesamt für Umwelt BAFU, Bern, Schweiz, und der Ruhr-Universität Bochum, Deutschland, gefördert

Perception-based noise assessment of a future blended wing body aircraft concept using synthesized flyovers in an acoustic VR environment—The ARTEM study

New aircraft concepts are currently being developed with the goal of less emissions of CO2 and noise. Remarkable noise reductions in long-range aircraft can only be expected from disruptive vehicle designs, new propulsion systems and specific low-noise technologies. In this paper, one such future vehicle design, a blended wing body (BWB) long-range aircraft, is described and studied with respect to sound levels on the ground, sound characteristics and noise annoyance. Virtual flyovers of different vehicle variants were synthesized and auralized in an acoustic VR environment, and investigated through psychoacoustic laboratory experiments. The applied methodology was successfully hierarchically validated by comparison with measurements of existing jet aircraft, assessing acoustical indices, time-frequency features, perceived plausibility, and induced noise annoyance. The perception-based evaluation of the BWB revealed that, while the BWB aircraft may initially be perceived as somewhat more unfamiliar, they are substantially less annoying than current tube-and-wing long-range aircraft of similar range and mission for take-offs as well as for landings. For the best BWB variant, noise annoyance was reduced by 4.3 units for departures and by 3.5 units for approaches on the 11-point scale. The main reason for these findings seems to be the acoustic shielding by the body of the extended fuselage, which was found to be an important factor in reducing sound levels in the order of 10–20 dB, and accordingly also to strongly reduce loudness. Additional low noise technologies and geared turbofan engines with a high bypass ratio further contributed to the reduction of noise annoyance of the BWB. A large part of the BWBs benefit could be explained by its lower sound levels, but additional benefits were found. The observed reduction in noise annoyance was found to be larger than what can be explained with conventional noise metrics. This benefit is probably due to more favorable sound characteristics compared to today's reference aircraft, such as less variation in time and less audible tones. The current study thus suggests that the studied BWB vehicle concept may substantially reduce noise annoyance on humans

Towards an uncertainty analysis for parametric aircraft system noise prediction

Parametric noise assessment in the context of low-noise aircraft design and flight procedure optimization has been around for more than 15 years. Continuous improvement of the models and the interconnection to other simulation tools, such as aircraft design codes, allow today's models to capture the major noise sources and relevant interactions along arbitrary simulated flights. Modem simulation processes even enable a fully automated aircraft design with integrated noise prediction capabilities. In contrast, reliable and comprehensive uncertainty analysis of the overall aircraft noise prediction process has not been available for parametric tools in the past. This paper will present ongoing DLR activities to assess the overall uncertainty of its in-hause simulation process. The goal of the presented analysis is to define a general approach to specify uncertainties on the ground noise levels as predicted by a parametlic system noise prediction tool, i.e. PANAM. This approach will allow to discuss the temporal and the spacial distribution of the uncertainties. Certain areas along a flight path are afflicted with different uncertainties than others. The impact on exposure-response relationships due to the valiation in uncertainty will be discussed, i.e. the influence of varying noise source dominance along the simulated flights. Initial results of uncertainties along typical flight procedures and their impact on selected metlics are presented in this contlibution