Air pollution causes 3.3 million premature deaths globally every year, and that number could increase to 6.6 million by 2050 if present trends continue, according to a comprehensive study done by researchers from Germany, Saudi Arabia, Cyprus and Harvard University, Associated Press reports.
"This is an astounding number," lead researcher Jos Lelieveld of the Max Planck Institute for Chemistry told CNN. "In some counties air pollution is actually a leading cause of death, and in many countries it is a major issue."
The number one cause of air pollution is burning wood and coal for domestic use, such as cooking and heating homes. This factor is responsible for a third of all air pollution-related deaths all over the world.
"Residential energy use is an inefficient form of fuel combustion that causes a lot of smoke, and is the foremost source of premature mortality in Asia," Lelieveld told Live Science. Seventy-five percent of all air pollution mortalities occur in Asia.
In Europe and in industrial countries like the U.S., Japan, Russia and South Korea, the primary cause of air pollution is farming - not nuclear plant emissions or car exhaust as popular belief would dictate and as the researchers themselves previously assumed. The ammonia released from fertilizers combines with sulfates and nitrates from the environment, forming soot particles, which are major causes of air pollution-linked deaths.
"We were very surprised, but in the end it makes sense," Lelieveld told Associated Press.
One surprising discovery from the study is that stroke and heart attack comprise 75 percent of deaths linked to air pollution, while respiratory illnesses and lung cancer merely comprise 25 percent, according to Live Science.
The researchers were able to calculate the effects of air pollution by using a "global atmospheric chemistry model." They integrated various global atmospheric quality models with satellite data and information on health, population and air quality sensors. Their study, so far, has the most detailed data on air pollution causes and deaths.
According to study results, China has the most number of air pollution deaths with 1.4 million premature mortalities annually. India comes next with 645,000 deaths, while Pakistan is third with 110,000 air pollution-related premature deaths each year.
"If this growing premature mortality by air pollution is to be avoided, intensive air-quality-control measures will be needed, particularly in South and East Asia," Lelieveld told Live Science.
The study was published in the Sept. 16 online issue of the journal Nature.
