Airborne pollutants can cause permanent biochemical and immunological changes in respiratory tissues, and the systems of the young are particularly vulnerable to damage which may be long-lasting.
Asthma now afflicts as many as one in seven European schoolchildren. Children are more vulnerable than adults because they have proportionately narrower airways, which are more easily obstructed, and their oxygen demand is higher (a nine-year old has to breathe in 25% more air, relative to body weight, to get the same amount of oxygen as an adult). Children in Czech and Slovak industrial areas have twice the average rate of respiratory infections.
New evidence is emerging that children living near roads with heavy vehicle traffic have about a 50% higher risk of suffering from respiratory symptoms than children living in areas with low traffic.
In 1997, one in seven children in the UK suffered from asthma, which is exacerated by air pollution: 13 times as many were admitted to hospital with the disease each year as in 1960.