Even a modest and gradual improvement in air quality could lead to great public health benefits, including preventing thousands of deaths, shows a new Canadian study that is said to be among the strongest ever conducted on this subject.
Health Canada researcher Hong Chen and his colleagues concluded that a 10% reduction in PM2.5 ultra-fine particle emissions over the duration of their study would have prevented 710 deaths per million people, or an economic value of $4.6 billion per million people. The faster and more intensive the reduction in PM2.5 particulate emissions, the lower the mortality and the greater the economic benefits, they said. “The effects of pollution are due to past exposure, so the approach they use helps to understand the impacts on mortality across the years,” explained Professor Audrey Smargiassi, from the School of Public Health in the University of Montreal.
“They really did all kinds of scenarios, some more realistic than others, to see what the impact would be. The conclusions that we draw are also new because they provide a perspective that we did not have to understand the impacts of reducing pollution. » PM2.5 particles are so fine that they can lodge in the hollow of the lungs and cause health problems; they are also the ones most studied and best understood by scientists. Man-made PM2.5 particulate emissions are estimated to have been responsible for 4.1 million deaths globally in 2019.
The study authors sifted through census data to capture a cohort of 2.7 million Canadian adults between 2006 and 2017. They also studied satellite data of PM2.5 particle emissions. They then carried out computer modeling of a reduction in emissions of these particles from the five main human sources in Canada: agriculture, industry, energy production, residential combustion and transportation. The effects of pollution, reminds Professor Smargiassi, are felt in the long term: the pollutants breathed in today could be the cause of health problems in ten, fifteen or twenty years. It is therefore important to study and better understand the long-term impact of improvements made now.
“It’s super important to understand that, she said, because to reduce pollution completely today, we are not able to do that. But we are capable of having substantial impacts, almost as high as if we had no pollution at all, if we did it gradually. So that gives us information on the impacts of the interventions, then what kind of intervention could lead us to significant gains. In other words, she continues, the data from the new study indicates that incremental improvements could eventually have an impact very similar to that of an instantaneous (and obviously unrealistic) disappearance of all air pollution. “Even with more realistic interventions, but spread over several years, we would be able to obtain gains almost as high as if today we stopped all the pollution,” said Professor Smargiassi.
But again, it is only in the long term, and even in the very long term, that the impacts of improvements made today would be felt. “I think this is a study that specifically targets governments, much more than the individual,” concluded Ms. Smargiassi. It targets the interventions that governments should put in place. It tells them that it is worth putting in place even interventions that are not so drastic, because in the end, they will have significant impacts. The findings of this study are published by the scientific journal Proceedings of the National Academy of Science.
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