The COVID-19 pandemic lockdown measures enforced in March 2020 resulted in record-low levels of air pollution, noise, and physical activity in cities.
The health repercussions of these alterations varied depending on the severity of the confinement measures and the local context, providing insight into how emergency measures can affect population health more broadly.
What can be gained from this experience in terms of future urban planning strategies and emergency preparedness?
The Barcelona Institute for Global Health (ISGlobal), a facility financed by the “la Caixa” Foundation, released a study on environmental pollution that aimed to answer these questions.
The research team chose three European cities with varying degrees of confinement measures to compare: Barcelona, where a strict lockdown was imposed, including law-enforced home confinement; Stockholm, where the measures were much more relaxed and ultimately subject to individual responsibility and “common sense”; and finally, Vienna, which had intermediate measures.
They gathered or estimated data on air pollution, noise, and physical activity in each of the three cities at three separate times: before the pandemic, during the acute confinement, and during the subsequent deconfinement phase.
The researchers calculated the variations in these environmental exposures and health behaviors between pre-pandemic and post-pandemic levels in the first phase.
In a second step, those differences were compared to existing health data to determine how many annual diagnoses of heart attacks, strokes, depression, and anxiety could have been prevented or increased in each city if changes in air pollution, noise, physical activity, and greenspace visits had been extended for a year.
Physical activity levels have dropped by up to 95%.
The study’s initial findings revealed that the severity of the confinement measures was directly associated with the decrease in exposures and behaviors investigated.
As a result, the city with the strictest restrictions, Barcelona, saw the greatest reductions in air and noise pollution, physical activity, and greenspace visitation compared to pre-pandemic levels.
Specifically, nitrogen dioxide (NO2) concentrations dropped by 50% on average during the first lockdown, daily noise levels dropped by 5 decibels (dB A), and physical activity dropped by 95%.
During the same time period, NO2 pollution in Vienna declined by 22%, average daily noise levels decreased by 1 dB (A), and physical activity decreased by 76%.
Daily noise levels dropped by 9% in Stockholm, while physical activity levels dropped by 42%.
Physical activity as a factor of health
The scientists estimated the impact of each of these alterations on health after quantifying the differences in each city relative to pre-pandemic levels.
They did so by drawing on evidence from earlier studies that found links between each of the exposures and behaviors evaluated and a variety of cardiovascular illnesses and mental disorders.
Finally, a data model was used to replicate the impact of the containment measures if they had been implemented for a full year, in order to depict the true magnitude of the changes studied in the long run.
Physical exercise was the major driver of health outcomes across all the factors studied. As a result of the reduced physical activity, a hypothetical year of rigorous confinement in Barcelona would have resulted in a 10% rise in strokes and heart attacks, as well as an 8% and 12% increase in diagnoses of depression and anxiety, respectively.
A year of reduced physical activity in Vienna might have resulted in a 5% rise in the annual incidence of strokes and heart attacks, as well as a 4% and 7% increase in diagnoses of depression and anxiety, respectively.
If the condition had continued for a year in Stockholm, the city with the smallest drop in physical activity levels, there would have been negative health consequences.
The model predicted a 3% increase in the occurrences of strokes and heart attacks, as well as a 2% increase in depression diagnoses and a 3% increase in anxiety cases.
Pollution and noise, on the other hand, make for excellent recordings.
The reductions in data on air and noise pollution had a good impact. In the city of Barcelona, an estimated 5% of heart attacks, 6% of strokes, and 11% of depression diagnoses could have been avoided if the reduction in NO2 concentrations from the first lockout had been sustained for a year.
In Vienna, strokes and heart attacks would be reduced by 1%, while depression would be reduced by 2%. The beneficial health impact in Stockholm would be the prevention of 1% of depression diagnoses.
Improved noise levels in Barcelona could have averted an estimated 4% of annual heart attacks, 7% of strokes, and 4% of diagnosed depression in the long run.
In Vienna, the rate of myocardial infarction, stroke, and depression might have been cut by 1%. Finally, noise reduction is expected to result in a 2% reduction in diagnosed heart attacks and depression, as well as a 4% reduction in stroke cases in Stockholm.
Negative equilibrium
“Despite the variances revealed in the three cities, there is a unifying pattern: the health benefits of enhanced air quality and noise do not outweigh the profoundly negative effects of reduced physical activity levels,” says Sarah Koch, ISGlobal researcher and the study’s first author.
In terms of urban health, the confinements and subsequent deconfinements provided us with the opportunity to gather useful data and learn more about how emergency procedures like lockdowns might affect the population’s health.
“Our findings demonstrate the potential benefits of implementing urban planning policies that reduce air pollution and noise while encouraging physical activity and contact with green spaces,” says Mark Nieuwenhuijsen, the study’s last author and director of ISGlobal’s Air Pollution and Built Environment program.
Barcelona Institute for Global Health
Methodology
The study compared the health hazards associated with each exposure and behavior assessed in the pre-pandemic stage to the acute confinement and deconfinement scenarios using a program called UTHOPIA.
It was based on public sources to find out how many people in each city had cardiovascular disease and mental health problems.
