Increased exposure to particulate matter PM2.5 air pollution, even when it is only very brief, is associated with a rise in the likelihood of young children developing acute lower respiratory infection (ALRI), a new study has found.
That study, published in the American Journal of Respiratory and Critical Care Medicine, found that such fine-particulate air pollution exposure was also associated with an increase in doctor visits, unsurprisingly.
“The most important finding of this study is that infectious processes of respiratory disease may be influenced by particulate matter pollution at various levels,” commented study author Benjamin Horne, PhD, director of cardiovascular and genetic epidemiology at the Intermountain Medical Center Heart Institute in Salt Lake City (Utah). “The exact biological implications of the study’s findings require further investigation.”
The basic point, though, is easy to understand: short-term exposure to fine-particulate air pollution (common anywhere that there are roads, combustion of any kind, and/or agriculture) is intimately involved with the development of lung infections in humans.
The press release provides more: “Dr Horne and colleagues studied 146,397 individuals who were treated for ALRI between 1999 and 2016 at Intermountain Healthcare facilities throughout Utah’s Wasatch Front region. The Wasatch Front is approximately 80 miles long and 10-20 miles wide, bordered on both sides by mountains. It consists primarily of suburbs, but also includes the cities of Salt Lake City, Ogden, and Provo/Orem.
“PM2.5 levels were estimated based on data from air quality monitoring stations along the Wasatch Front, where approximately 80% of Utah’s population resides. Measurements were also made at secondary locations. Short-term periods of PM2.5 elevation were matched with the timing of increases in healthcare visits for ALRI…The research team found ALRI associated with elevated levels of PM2.5 in both children and adults — even in newborns and toddlers up to age 2, who represented 77% (112,467) of those who had an ALRI diagnosis.”
Unambiguous results. It should be remembered here of course that around 60% of US children currently live in regions where airborne PM2.5 concentrations notably exceed air quality standards. The standards being exceeded are, as we’ve reported previously, themselves not actually sufficient to avoid highly negative outcomes.
So the situation that we are in is one whereby current air quality standards aren’t sufficient; where despite not being sufficiently strict, they are still being exceeded over a majority of US territory; and where the implications of this are becoming more and more apparent every year.
Dr Horne noted: “The air pollution itself may make the human body more susceptible to infection or may impair the body’s ability to fight off the infectious agents. It may be that PM2.5 causes damage to the airway so that a virus can successfully cause an infection or that PM2.5 impairs the immune response so that the body mounts a less effective response in fighting off the infection. This could lead to longer periods of ALRI symptoms or more severe symptoms requiring a higher intensity of medical care for the infected individual. It may also be that periods of acute increases in PM2.5 lead people to stay indoors more where they are in closer contact with others who carry infectious agents and can transmit the infection to them.”
On that note, of course, it’s also the case that indoor air is often notably more polluted than outdoor air (though, this varies with regard to particulate pollution based on a number of different factors).
With regard to fine-particulate air pollution itself, around half of it in urban areas is the result of motor vehicles, with small businesses (gas stations, dry cleaners, cleaning services, etc.) responsible for another ~40%, and large industry a further ~10%.
Featured Image courtesy US EPA