What is the significance of the research for young children?
The Swedish findings potentially have significant mental health implications for young children in the UK given that the researchers found an association with psychiatric disorders and NO2 concentrations lower than 15 μg/m3. In many UK cities, NO2 concentrations are many times greater than this, particularly during daily traffic peaks – times of the day that coincide with children travelling to and from nurseries and schools. While we do not know exactly how higher concentrations of traffic-related pollution affect mental illness, research suggests they lead to more severe illness.
Does wider research add to the results, especially relating to young children and babies?
Pregnancy, infancy and early childhood are critical times. Rapidity of change means that environmental insults such as air pollution cannot only have a greater influence on important organ systems but also, once damage occurs, there may not be the capacity to recover. Added to this, infants have a relatively high metabolic rate, so they inhale a greater volume of air per minute than an adult, and their main modes of outdoor transport (car or pushchair) optimally expose them to motor vehicle exhaust emissions.
While more evidence of a causal link is needed, do you think that it is time to act?
We have evidence from other research studies that reducing air pollution brings about appreciable improvements in public health. The ever-accumulating evidence that air pollution contributes to such a diverse set of disease outcomes confirms the urgent need to manage the quality of the air we breathe.
What can be done?
To improve urban air quality, traffic must be reduced and we must ensure a cleaner and greener element to what remains on the road. More effective low-emission zones, investing in clean and affordable public transport, moving back from diesel to petrol (or at least banning all highly polluting diesel vehicles), lowering speed limits and enhancing cycle routes can all help. Awareness campaigns will also achieve a durable change in public behaviour.
Is there anything that can be done in specific high-risk areas?
Everyone – government, employers, schools, the public – has some responsibility for reducing pollution. In our cities, where schools are in close proximity to busy roads, alternatives to car travel must be encouraged, based on public transport or active options (walking, cycling). If you are going to drive to nurseries and schools, then petrol cars are far preferable to diesel ones.