Rising air pollution levels around the world are increasing the likelihood of people dying early, a comprehensive new study finds. In Australia, where air pollution is historically low, an increase in soot air has led to a sharp increase in the number of former deaths.
More air pollution means more deaths, even with low levels of air pollution and low exposure, according to the study, which measured particulate and daily mortality rates in 652 cities in 24 countries over a 30-year period. It is the largest international study to date on the short-term effects of air pollution on death and has been published in the New England Journal of Medicine.
There are already numerous studies on how this type of pollution makes people sick. Inhaling particles from dust, ashes and burning fossil fuels can damage the heart and lungs. It has been associated with chronic lung and heart problems as well as early death. Today's study shows that even small amounts of particles can be dangerous.
The results are now particularly significant as the Amazon rainforest is burning at some of the fastest ever land rates in Brazil, which has Australia's second-highest mortality rate. In Brazil, the Amazon rainforest is currently burning at the highest rates ever recorded in the country. And these forest fires produce fine dust. The smoke of the fire was so strong that it darkened the sky in São Paulo. Brazilian President Jair Bolsonaro has pledged to open the Amazon for agricultural and mining interests, making it vulnerable to slash and burn.
To determine actual early deaths, researchers compared daily mortality rates over the study period. Compared with the daily death rates at the beginning, there was an increase in deaths on days when air pollution increased.
If you look at the percentages, the increases appear small. For all causes of death, mortality rates increased consistently by 0.44 percent, as the amount of coarse particulate matter increased slightly. For particulate matter, which is smaller and can enter the deep lung when inhaled, mortality rates increased 0.68 percent with increasing concentration. But less than 1 percent of the world's population is still millions of people.
"When we consider a population of one million people in a city, a good one percent is significant and can affect many people," says Eric Lavigne, co-author of the study, The Verge . Lavigne is a professor at the University of Ottawa and senior epidemiologist for the Canadian Public Health Agency.
Some countries in the analysis, such as the US, have already taken measures to keep air pollution at bay. Nevertheless, the death rates increased with increasing environmental pollution. That means there is still much room for improvement. "We can still affect public health if we become cleaner than we already are," says John Balmes, a spokesman for the American Lung Association, which teaches at the University of California at San Francisco and Berkeley.
Balmes adds, "A relatively low risk that affects the entire population may be as important to public health as a stronger risk factor that not everyone experiences [like smoking]."