Air pollution may aggravate nasal suffering with colds and seasonal allergies

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.