Do you have a runny nose all year round, even when it’s not allergy season and you’re not suffering from a cold?
Scientists have discovered in a new study that air pollution can cause inflammation in the nasal passage and sinus tissues which can lead to a runny nose all year round.
In tests carried out on mice, researchers found air pollutants damaged the upper respiratory system.
It has long been known that these pollutants and smog raise rates of respiratory problems like asthma, however, this is the first time it has been linked to the sniffles.
To test the theory, 38 eight-week-old mice were exposed to either filtered or unfiltered air from a city five days a week for 16 weeks.
The mice that were exposed to pollution presented with a higher white blood cell count after that time, indicating they were suffering from higher levels of inflammation.
They also had higher levels of messenger RNA – the blueprints of DNA needed to make proteins – in the genes associated with inflammation.
Dr Ramanathan said: “Inflammation that attracts eosinophils [a type of white blood cell] is what happens in the lungs of people with asthma, so essentially the chronic exposure to air pollution in mice is leading to a kind of asthma of the nose.”
Further tests showed the surface layer inside the nose of the mice who had breathed in the pollution was 30 to 40% thicker than the ones who hadn’t.
They also found much higher levels of the protein serum albumin in the mice that breathed in the polluted air, which indicates the pollutants had broken through the barrier in the nasal passage and sinuses.
Dr Ramanathan said: “We’ve identified a lot of evidence that breathing in dirty air directly causes a breakdown in the integrity of the sinus and nasal air passages in mice.
“Keeping this barrier intact is essential for protecting the cells in the tissues from irritation or infection from other sources, including pollen or germs.”
