Unpleasant side effect: If the runny nose is particularly severe, this can also be due to air pollution. A high level of particulate matter and nitrogen oxides exacerbates the symptoms of such rhinitis, as a study in 17 European cities has now shown. This is probably due to the double exposure of the respiratory cells by the viruses and the oxidative stress of the pollutants.
A runny nose, sneezing attacks and swollen, inflamed mucous membranes: runny nose is particularly common in winter. The highly contagious rhinoviruses are primarily responsible for this. But how often and how bad such a rhinitis affects us does not only depend on personal disposition. Cold and tobacco smoke can also promote the infection, as studies have shown.
Targeting fine dust and nitrogen oxides
Researchers led by Emilie Burte from the Barcelona Institute for Global Health (ISGlobal) have now identified another influencing factor: air pollution. This was triggered by the observation that particulate matter and nitrogen oxides can worsen the symptoms of asthma. “That’s why we wanted to know whether long-term exposure to air pollutants also plays a key role in rhinitis,” explains Burtes colleague Benedicte Jacquemin.
For their study, the researchers analyzed data from 1,408 rhinitis patients from 17 European cities, including Paris, Barcelona, Antwerp, Umea and Erfurt. They used surveys to determine the severity of the symptoms and the course of the infection. They used data from a European air measurement project for air pollution at the participants’ place of residence.
With increasing stress, the symptoms worsen
The result: Both fine dust and nitrogen oxides play a role in the severity of the cold symptoms. Participants who had long-term high levels of particulate matter PM10 and PM2.5 in their residential areas suffered more from rhinitis than patients from less polluted areas. The same was true for air pollution with nitrogen oxides, as the scientists report.
On average, every increase in PM2.5 values by five micrograms per cubic meter of air increased the risk of a severe course by 17 percent, said Burte and her colleagues. Specifically, this manifested itself in a greater irritation of the mucous membranes, more frequent sneezing and a greater congestion of the nose. An increased nitrogen oxide exposure, on the other hand, led to an increased mucus flow with a blocked nose.
According to the researchers, this proves that air pollution not only has many long-term health consequences, but can also affect the severity of acute runny nose.
Double exposure to oxidative stress
But why? “The effect of the air pollutants on the severity of the symptoms is probably related to the fact that they cause oxidative stress, promote inflammation and activate the cells’ suicide program,” explains Burte. Similar to tobacco smoke, the double exposure to oxidative stress and viral pathogens seems to overwhelm the mucosal cells.
However, fine dust and nitrogen oxides seem to have different effects: “This could be due to the fact that these pollutants have different mechanisms of action and therefore also cause different inflammatory reactions in the respiratory tract,” explains Burte. “But to confirm this hypothesis, we need more studies.” (Journal of Allergy and Clinical Immunology, 2020)
Source: Barcelona Institute for Global Health (ISGlobal)
–
