An exhaust pipe of a car is pictured on a street in a Berlin, Germany, February 22, 2018. (Photo Credit: REUTERS/Fabrizio Bensch)
People who get rhinitis - an inflamed or congested nose - from colds or allergies may feel much worse if they're exposed to high levels of air pollution, a recent study suggests. Rhinitis usually involves some combination of congestion, sneezing, nasal irritation and sometimes a reduced sense of smell, and it affects up to half of the world's population, the study team writes in Journal of Allergy & Clinical Immunology.
"Breathing polluted air will cause inflammation and oxidative stress on the respiratory tract," said lead study author Emilie Burte of INSERM in Villejuif, France. "That probably will increase the frequency or severity of rhinitis symptoms," Burte said by email. Even though rhinitis is especially common among people with asthma - a condition that's aggravated by air pollution - research to date hasn't offered a clear picture of how air quality impacts the severity of rhinitis.
For the current study, researchers examined data on air pollution exposure and symptom severity for about 1,400 people with rhinitis in 17 European cities. Two types of pollutants in particular were associated with worse rhinitis symptoms: nitrogen oxide, a byproduct of fossil fuel combustion that contributes to smog; and so-called PM 2.5, a mixture of solid particles and liquid droplets smaller than 2.5 micrometers in diameter that can include dust, dirt, soot and smoke.
People in cities with the highest levels of PM 2.5, or fine particulate matter, reported the most severe rhinitis symptoms. Each increase of 5 micrograms per cubic meter of air (mcg/m3) in concentrations of fine particulate matter was associated with a 17% higher chance that people with rhinitis would experience severe symptoms, the study found.
Fine particulate matter was associated with worse congestion, nasal irritation and sneezing. Nitrogen dioxide was also tied to more severe rhinitis, particularly for symptoms like nasal discharge and congestion. The pollutants exacerbating rhinitis in the study have long been linked to traffic fumes, with worse air quality around major roadways in cities around the world. While the study wasn't designed to prove whether air pollution causes rhinitis or makes symptoms worse, it's possible that each kind of contaminant in the air does its own type of damage in the respiratory system, Burte said.
People prone to colds and allergies can't do much to prevent pollution from making rhinitis worse, aside from staying indoors, said Yaguang Wei, an environmental health researcher at Harvard University in Boston who wasn't involved in the study. People can pay attention to air quality alerts for their city or community and plan to stay indoors or at least avoid vigorous activity outside during peak pollution times.
"For indoor air pollution, air purifiers can clean indoor air and protect your family, especially for children and the elderly," Wei said by email. People can also do their part to reduce traffic fumes. "Using public transportation can help reduce air pollution emissions," Wei said.