Health impacts of a reduced aircraft noise exposure during the Covid-19-pandemic - A natural experiment in Stockholm, Sweden

Abstract

Background and aim: The lock-downs during the Covid-19-pandemic induced significant changes in travel patterns. In Stockholm, Sweden, the aircraft traffic around Bromma airport reduced by 77 percent during the first wave of the pandemic, March 1 to June 15, 2020, resulting in a sharp decline in residential exposure to noise. Based on this "natural experiment”, we aimed to assess the impact of the reduced aircraft noise exposure on population well-being and health. Methods: In September 2020, we invited 10 000 individuals residing in the vicinity of Stockholm Bromma airport (n=7 500) and in Nacka municipality (n=2 500), serving as a reference, to a web-based questionnaire survey. The questions related to a pre- and during the pandemic situation, respectively, and concerned individual and housing factors and various disturbances, e.g., noise annoyance, sleep impairment, and stress related symptoms. Residential exposure to aircraft noise was assessed for a pre-pandemic situation in 5 dB categories ranging from ≤45 to ≥55 dB Lden. Logistic general estimating equation models were used to assess Relative Risks (RR) and 95% Confidence Intervals (95% CI). Results: In total, 3 582 individuals responded to the survey (35,8%). In the pre-pandemic situation, statistically significant associations were found between aircraft noise and all investigated disturbances. During the pandemic, the associations reduced and approached unity. The RR for high noise annoyance dropped from 7.51 (95% CI 5.18-10.90) among those exposed ≥46 dB Lden compared to the reference before the pandemic, to 2.18 (95% CI 1.24-5.9) during the pandemic. Corresponding figures for high sleep disturbance were 7.64 (95% CI 3.90-15.0) and 1.57 (95% CI 1.62-1.02), respectively. Improvements were also seen for stress symptoms. Conclusions: The reductions in aircraft noise exposure around Stockholm Bromma airport during the Covid-19-pandemic resulted in an overall improved health in the local population. Keywords: Aircraft noise, Covid-19-pandemic, annoyance, sleep, stress