The air quality temporarily improved during first wave of covid-19, due in large part to restrictions on mobility, but to date it was unknown how this reduction had affected the health of the population in Spain.
Now, a study led by the Barcelona Institute for Global Health (ISGLOBAL), together with the Barcelona Supercomputing Center, National Center for Supercomputing (BSC-CNS), estimates that this improvement prevented around 150 premature deaths in the country’s provincial capitals.
Various analyzes have estimated the reduction in mortality due to improved air quality during periods of confinement in China and Europe, showing a substantial number of premature deaths averted.
This work was focused for the first time in Spain and, specifically, in 47 provincial capitals
This new work, published in the journal Environmental Pollution, focused for the first time on Spain and, specifically, on 47 provincial capitals. In the first place, the changes in the levels of atmospheric pollution – nitrogen dioxide (NO2) and ozone (O3) – during the periods of confinement (57 days) and deconfinement¬ (42 days) of the first epidemic wave of the covid-19, between March and June 2020. The team then estimated the impact of these air quality changes on population mortality.
Comparison with historical health and pollution data
Hicham Achebak, first author of the study and researcher at ISGlobal and the Center for Demographic Studies (CED), highlights the methodology used in the study: “We have taken into account the influence of meteorological factors by quantifying the effect of confinement on air quality levels, through machine learning techniques ”.
In addition, the researcher adds that to estimate the changes in the mortality“The study is based on an epidemiological model that has been specifically adjusted in each of the provincial capitals with historical data on health and air pollution.”
The results of the study show that NO2 levels were reduced by 51% and 36% during confinement
The results of the study show that NO2 levels were reduced by 51% and 36% during the confinement and deconfinement of the first wave of covid-19, respectively. Also, on average, the ozone it fell much less, by 1.1% and 0.6%, respectively, although it increased in some of the most populated cities.
Regarding the impact of the decrease in NO2 Regarding premature mortality, the study estimated that around 120 deaths during confinement and about 50 deaths during deconfinition were avoided, that is, a total of approximately 170 premature deaths.
The confinements Covid-19 have led to “unprecedented reductions in NO2 concentrations, especially when the strictest measures were applied to reduce the transmission of the virus, reaching up to 65% in some of the cities studied,” he explains. Hervé Petetin, researcher at the BSC-CNS and responsible for the application of machine learning techniques. Most NO2 emissions in cities come from vehicles, especially diesel.
Minimal ozone depletion
In the case of ozone, the reduction was so minimal that it failed to prevent premature mortality. In fact, it is estimated that premature mortality increased by approximately 20 deaths related to this pollutant during the entire period studied.
Carlos Pérez García-Pando, ICREA and AXA professor and head of the BSC-CNS atmospheric composition group that participated in the study, explains that this occurs because, “despite the small average reductions during the analyzed period, there was an increase in ozone levels in the most populated cities, especially Barcelona and Madrid”.
There was an increase in ozone levels in the most populated cities, especially Barcelona and Madrid
Carlos Pérez García-Pando
“Ozone is a secondary pollutant that can increase when the nitrogen oxides in environments saturated with this pollutant, such as in large urban areas. When evaluating the impacts of environmental exposures on health, the possible trade-offs between multiple pollutants should be taken into account, ”says Pérez García-Pando.
The results could be even greater
Joan Ballester, an ISGlobal researcher who coordinated the study, highlights that the number of preventable deaths due to the improvement of air quality in Spain could be higher. “On the one hand, the study focuses on the provincial capitals, but there are other cities with high levels of air pollution and, on the other, the reductions in fine particulate matter have not been taken into account, which were relatively modest compared to the NO2 reductions, but which most likely contributed to a further reduction in premature mortality ”.
The reductions in fine particulate matter which were relatively modest compared to the reductions in NO2 have not been taken into account.
These findings show the great health benefits This means reducing air pollution in the short term and, with permanent emission reductions, the positive effects could be much greater.
In addition to decreasing the premature mortality, the researcher emphasizes that improving air quality “could reduce the burden of disease from epidemics that cause respiratory infections such as covid-19, since diseases caused by prolonged exposure to air pollution are in turn risk factors for severity and mortality from the coronavirus ”.
Hicham Achebak et al. “Trade-offs between short-term mortality attributable to NO2 and O3 changes during the COVID-19 lockdown across major Spanish cities”. Environmental Pollution.
Rights: Creative Commons.