There is now sufficient evidence to link traffic pollution to the development of childhood asthma, according to a study carried out by the University of Leeds and the Barcelona Institute for Global Health (ISGlobal), published in the journal Environment International in late November.
The study harvested data from 41 epidemiological studies in a number of countries, including the USA, Sweden, Germany, Holland and Britain.
Asthma and allergic rhinitis prevalence has been growing in many countries since the late 1980s. According to the WHO, asthma ranks as the most common chronic disease among children today and is caused by exposure to irritants ranging from air pollution to indoor allergens such as house dust mites in bedding and carpets, chemicals and air pollution.
The Leeds and ISGlobal scientists said key culprits behind the rising asthma rates in children were PM2.5 and PM10 particles in the air and also nitrogen dioxide (NO2). One of the Leeds researchers, Haneen Khreis, speaking to Air Quality News, said the most robust effects were associated with black carbon, associated with traffic exhaust fumes and diesel-engine pollutants. Finer particle pollutants like black carbon are becoming more widely acknowledged but tend to be omitted from air quality monitoring standards.
The researchers concluded that the high degree of consistency in their findings indicated “there is now sufficient evidence to support an association between the exposure to TRAP (Traffic Related Air Pollution) and the development of childhood asthma”.
Commenting on the study, Bengt Rittri, founder and CEO of indoor air cleaning technology firm Blueair, said: “The study for the first time indicates a clear association between traffic exposure and the onset of asthma, which is alarming in a world where WHO says 90 percent of people are breathing polluted air.”