Bronchiolitis in infants mostly affects those younger than two months old.

Signs of severe bronchiolitis include retractions and can lead to more severe disease, such as pneumonia and asthma.

Compared with subjects who had less than 100 metres of road length within a 200-metre radius of their home, those with more than 500 metres of road length had a 1.6 times greater risk of infantile bronchiolitis, according to a study conducted by a team of medical doctors at South Korea’s Inha University.

The research was based on 2,627 school children between 6 and 14 years old who had participated in a longitudinal follow-up survey.

“The study proves a hypothesis that children who are exposed to an environment with no protection from noise and fine dust are at higher risk of having asthma,” said Leem Jong-han, who led the study’s research team.

The research was published in the latest edition of the Journal of Asthma.