Two recent studies correlate winter air pollution to short-term health risks along the Wasatch Front.
We’ve long known the hazards of a lifetime spent breathing polluted air, but the short-term health effects of pollution spikes are murkier. Two recent studies cast the Wasatch Front as a natural laboratory to uncover links between respiratory infections and air pollution. They highlight the short-term risks of breathing contaminated air, especially for the old and very young.
“Every January or February, Primary Children’s Hospital seems to fill up with cases of RSV [respiratory syncytial virus],” says Dr. Benjamin Horne, Director of Cardiovascular and Genetic Epidemiology at Intermountain Medical Center (IMC) Heart Institute. After a conversation with a colleague, Horne says, “we wanted to see if there was an association between the timing of RSV and air pollution resulting from inversions,” especially in young children. RSV and influenza are among the viruses that can lead to acute lower respiratory infections in children, sometimes with serious complications.
The health consequences of poor air quality had been on more than a few minds at IMC: Unbeknownst to Horne, another researcher just down the hall was asking whether air pollution is connected to rates of pneumonia in older adults.
The pair of papers, published in April, add to the growing body of evidence linking a variety of maladies with air pollution. The researchers drew on past medical records from Intermountain Healthcare and contemporaneous air quality reports from EPA weather stations. Both teams found that spikes in the smallest class of air pollutants—fine particulate matter—correlated with the timing of acute lower respiratory infections.
Risk factors
Horne’s study, published in the American Journal of Respiratory and Critical Care Medicine, found that more children, adults and babies were diagnosed with acute lower respiratory infections one to four weeks following an inversion. Every time fine particulate matter (PM2.5) went up 10 micrograms per cubic meter, a person’s odds of seeking treatment increased 15-23%.
The researchers found that people were more likely to seek medical treatment for respiratory infections even when air quality was categorized as “moderate.” This correlation was especially strong for babies.
The second study, published in the Annals of the American Thoracic Society, found that more adults of all ages were treated for pneumonia within a week of poor air quality, with a particularly strong association for those over 65 years old. Lead author Cheryl Pirozzi, a pulmonary physician and researcher at the Department of Internal Medicine, says that every time PM2.5 increased 10 micrograms per cubic meter, odds of getting pneumonia in adults over the age of 65 increased by 35% and odds of death in the hospital increased by 50%. Pirozzi also linked winter nitrogen dioxide and summer ozone pollution to increased risk of pneumonia, although the effect was weaker than that of PM2.5.
“If you think of a typical inversion air pollution episode, the PM2.5 will often go higher than the EPA’s ‘unhealthy for sensitive groups’’ range,” Pirozzi explains. “So older adults would be approximately two-and-a-half times more likely to get pneumonia, two-and-a-half times more likely to be hospitalized with severe pneumonia requiring ICU admission, and about three times more likely to die from pneumonia in the hospital.”
Pirozzi’s team extrapolates that if PM2.5 always remained in the EPA’s “good” air quality rating (below 12 micrograms per cubic meter), there would be approximately 100 fewer hospitalizations for pneumonia in the seven hospitals studied, saving $476,000 to $807,000 in medical costs each year. Since these hospitals serve roughly half the population of the Wasatch Front, Pirozzi estimates that lowering 2.5PM air pollution could save $1.6 million in medical costs for the region.
Pollutants don’t cause the initial viral or bacterial infection, Horne emphasizes. And while both studies found strong correlations between air pollution and respiratory diseases, neither can show causation. “This was an epidemiologic study,” says Horne. “It doesn’t tell us what the causes are per se, [only] that there’s a very strong association” between air pollution and acute lower respiratory infections.
“They are two very important studies,” says Daniel Mendoza, a postdoctoral fellow at the Pulmonary Division of the School of Medicine and the Department of Atmospheric Sciences who was not involved with the research. “There could be further work done to more finely resolve spatial exposure differences. What’s really powerful here,” he adds, “is that we’re looking at a large population, looking at lower levels of pollution and their associations with disease outcomes. And while [these findings] are relevant, as they are local, they can be replicated in other areas that don’t have our high pollutant levels.”
What can we do?
As cold weather settles in, we’ll remind you to wash your hands, keep them away from eyes, nose and mouth to discourage viral or bacterial infections from spreading, stay indoors if you are among the most vulnerable, consider installing a HEPA filter and wear a good filter mask when going outdoors.
But some solutions to the problem of PM2.5s involve year-round engagement: For instance:
- If you smoke, start quitting now; this includes e-cigarettes.
- If you have a fireplace or wood stove, plan on limiting its use or invest in a gas appliance.
- Pay attention to the maintenance schedule of your vehicle or consider acquiring a more fuel-efficient vehicle (especially if your current ride is diesel).
- Support expansion of public transportation and bicycle infrastructure (and use them).
- Voice an opinion on regional projects that increase fine particulate matter.
- Learn about and vote for candidates who support air quality legislation, armed with knowledge from reports such as these.
“These are important studies for us here on the Wasatch Front,” says Pirozzi, “because it’s local data—it’s about the air we’re breathing. These studies show real risks for our community, and they show that air pollution is a real public hazard here in Utah.”
Faith Rudebusch is a biologist and the author of the edible gardening blog, slatemountaingarden.wordpress.com. She lives in Pocatello, Idaho.