Investigating the associations between road traffic noise exposure at home, green spaces and stress biomarkers: A cross-sectional field study

Chronic exposure to environmental stressors, like road traffic noise, is linked to negative health impacts. This cross-sectional field study investigates the associations between road traffic noise exposure at home, residential green, and stress biomarkers (cortisol and cortisone) among residents in the city of Zurich, Switzerland. The study involved 224 participants exposed to varying levels of noise at home and varying access to green spaces in the vicinity of home. Data collection included 3 cm near-scalp hair samples for cortisol and cortisone as biomarkers for chronic stress, residential environment assessments, and questionnaires. Exposure to road traffic noise at home was quantified through modelled L_den and residential green through the normalized difference vegetation index (NDVI) and percentage of public green spaces. Multiple linear regression models were used to study the association of the long-term physiological stress biomarkers with the exposure to road traffic noise at home and residential green. There was no association between noise exposure and stress biomarkers, while a significant negative association of cortisone (β = −0.0084; 95 % CI: −0.0162 to −0.0006; p < 0.05) and the sum of cortisol and cortisone (β = −0.0086; 95 % CI: −0.0165 to −0.0008; p < 0.05) was found with green space area in the neighborhood. These findings highlight the importance of public green spaces contributing to public health in urban settings.