About 2.5 billion people, or 86% of people living in cities around the world, suffer from varying degrees of air pollution. And many of them are at increased risk of cardiovascular, respiratory and other diseases.
This according to a new study at the Lancet Planetary Health magazine , whose authors found with the help of their new computer model that in the vast majority of cities around the world, levels of PM2.5 (a fine particulate matter with a diameter of 2.5 micrometers or less) exceed those recommended by the World Organization of health .
As a result, more than 1.8 million people die each year from various diseases caused or exacerbated by prolonged exposure to high levels of air pollution, scientists say.
“Although regional averages of urban PM2.5 concentrations declined between the years 2000 and 2019, we find considerable heterogeneity in trends in PM2.5 concentrations across urban areas,” they write.
“Regional averages of deaths attributable to PM2.5 have increased in all regions except Europe and the Americas, driven by changes in population numbers, age structures and disease rates. In some cities, attributable mortality from PM2.5 has increased despite declining PM2.5 concentrations as a result of changes in age distribution and rates of noncommunicable diseases.
Polluted air in major cities
mostly cities in the world, air pollution can be especially serious, which is alarming given that 55% of the nearly 8 billion people on the planet live in cities and their number is expected to grow in the coming years and decades . And as urban areas expand, so does air pollution.
In some regions, such as Southeast Asia, air pollution levels are getting worse, with the region recording a 27% increase in the population-weighted average concentration of PM2.5 between 2000 and 2019, the scientists found. “Deaths attributed to PM2.5 increased by 33% in those years, from 63 to 84 per 100,000 people,” they write.
During the same period, African cities saw an 18% decrease in PM2.5 concentrations and European cities saw a 21% decrease, while North and South American cities saw a 29% decrease.
“However, this has not been accompanied by the same level of decline in mortality rates attributable to PM2.5 alone. This means that other demographic factors, such as an aging population and poor health in general, are influential factors in pollution-related death rates,” the researchers said.
Reducing chronically high levels of air pollution will require far-sighted, comprehensive policies, scientists say.
“Avoiding the massive public health burden caused by air pollution will require strategies that not only reduce emissions but also improve overall public health to reduce vulnerability,” said Veronica Southerland, an expert at George Washington University in the United States and lead author. .
By Daniel T. Cross. Article in English