Slide 1 of 17
An estimated 3.3 million deaths worldwide are caused by outdoor air pollution, according to a study published in September 2015 in the journal Nature. Of those deaths, about 75 percent are from heart attacks or strokes, while about 25 percent are from lung-related ailments, Live Science previously reported.
The majority of these deaths — about 75 percent — happen in Asia, where air pollution is particularly severe, especially in China and India. Much of this pollution results from burning fossil fuels, and global carbon emissions are on track to reach record highs worldwide in 2017, according to a report released Nov. 13, 207, by the Global Carbon Project.
The link between cardiovascular health and air pollution is well-known, but recent studies are providing a growing body of evidence that polluted air can have a range of negative impacts on physical and mental health, leading to ailments that can in some cases prove lethal.
Poor quality spermSlide 2 of 17
Poor quality sperm
Elevated levels of air pollution have been linked to lower sperm quality, according to a study from Taiwan published Nov. 13 in the journal Occupational and Environmental Medicine.
Researchers investigated sperm production, activity and appearance over a series of three-month periods, in nearly 6,500 men living in Taiwan that were between the ages of 15 and 49. They then estimated how the subjects' sperm would be affected over a two-year period.
The scientists found an association between exposure to fine particulate matter in the air and abnormal sperm shape and size, they reported in the study. However, the amount of sperm produced tended to be higher when air pollution was present, perhaps to compensate for the compromised morphology of the individual sperm cells, the study authors noted.Slide 3 of 17
Fractures from bone density lossSlide 4 of 17
Fractures from bone density loss
In older people, osteoporosis — age-related bone density loss — is the most common cause of bone fractures, leading to approximately 8.9 million fractures in people around the world each year, according to the International Osteoporosis Foundation. And there may be a link between air pollution and greater vulnerability to broken bones from osteoporosis, scientists reported in a study published Nov. 9, 2017, in the journal The Lancet: Planetary Health.
Researchers first evaluated data from 9.2 million people over the age of 65, investigating hospital admissions for bone fractures in the northeast and mid-Atlantic United States from January 2003 to December 2010. They compared their findings about patients with broken bones to levels of particulate matter in the air — a component of air pollution — and found that the risk of bone fractures increased when pollution levels were higher, particularly in low-income communities.
In a second stage of analysis, the researchers looked at 692 middle-age men in the Boston area, examining the impacts of their exposure to air pollution over time. They observed that men living in regions where pollution from car emissions was higher, had lower levels of parathyroid hormone, which contributes to building and maintaining bone mass. The men in highly polluted areas also had greater drops in their bone density levels than study subjects living in less polluted neighborhoods, the scientists reported.Slide 5 of 17
Stroke riskSlide 6 of 17
Strokes kill an estimated 5 million people worldwide each year — they are the fifth leading cause of death in the United States and are a major cause of long-term disability, according to the Centers for Disease Control and Prevention. And incidences of stroke are on the rise, leading a team of researchers to question whether environmental factors could be to blame.
Scientists reviewed 94 studies reporting 6.2 million stroke cases in 28 countries around the world, occurring between 1948 and 2014. They were looking for associations between short-term exposure to air pollution — evaluating pollution from gasses and from particles in the air — and hospital admission or death resulting from a stroke.
They discovered a "marked and close association" between short periods of exposure to certain levels of air pollution and "adverse stroke outcomes" — disabilities and deaths — which they described in a study published in May 2015 in the journal BMJ. Though only 20 percent of the studies represented developing countries, air pollution levels tended to be highest there, and the number of strokes reported were also disproportionately high, the scientists wrote in the study.Slide 7 of 17
Kidney diseaseSlide 8 of 17