Hay fever linked to exposure to pollution before and after birth © Getty Images

Hay fever linked to exposure to pollution before and after birth

Babies are more likely to develop allergic rhinitis, a condition that includes hay fever, if they are exposed to higher levels of fine particulate matter before and after birth.

Babies who are exposed to pollution both before they are born and during their first year of life have a higher risk of allergic rhinitis, a condition that includes hay fever, scientists have suggested.

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A study has linked the amount of fine particulate matter that youngsters are exposed to with a risk of allergic rhinitis.

Allergic rhinitis is inflammation of the inside of the nose caused by an allergen, such as pollen, dust, mould or flakes of skin from certain animals. When pollen is the allergen, the condition is known as hay fever. It is a very common condition, estimated to affect around one in every five people in the UK.

Allergic rhinitis typically causes cold-like symptoms, such as sneezing, itchiness and a blocked or runny nose – which usually start shortly after exposure to an allergen.

Researchers, led by a team of experts from Taiwan, said the associations between pre- and post-natal exposure to fine particulate matter (PM2.5) and allergic rhinitis were previously not well understood. So they examined data on 140,000 babies born in Taiwan, whether or not they went on to develop the condition.

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This was cross-referenced with their levels of exposure to PM2.5 using a combination of methods including satellite time trend readings, meteorological variables, and land use data. A third of the children – 47,000 – went on to develop allergic rhinitis.

The researchers found a significant association of allergic rhinitis with rises in PM2.5 from 30 gestational weeks until the babies were a year old.

The concentration of an air pollutant is measured in micrograms (one-millionth of a gram) per cubic metre of air, or µg/m3. The researchers said that each 10 µg/m3 increase in PM2.5 was associated with 30 per cent higher odds of an allergic rhinitis diagnosis.

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“Our study provides evidence that both pre-natal and post-natal exposures to PM2.5 are associated with later development of allergic rhinitis,” the authors wrote in the journal Thorax. “The vulnerable time window may be within late gestation and the first year of life.”

How can I protect myself against air pollution?

Wear a mask – but make sure it fits

In terms of blocking particulates, surgical masks are shockingly inefficient. Despite their ability to filter the air, the lack of an effective seal around the edges vastly reduces the effectiveness.

That’s not to say that wearing a mask isn’t worthwhile in general. A 2018 study from the Institute for Occupational Medicine in Edinburgh measured the efficacy of various consumer face masks and found that the key factor in reducing the inhaled particulates isn’t the mask’s filtration efficiency, but how well it fits.

Learn more about how to protect yourself