It is clear from epidemiological and laboratory studies that air pollution has adverse effects on health. However, understanding whether ambient concentrations of nitrogen dioxide (NO2) have direct adverse effects on health has proved to be difficult, because levels in ambient air correlate closely with those of other pollutants, notably particles. This difficulty arises because NO2 and particles have similar sources, such as traffic.
Knowing whether or not current concentrations of outdoor NO2 have direct adverse health effects is becoming increasingly important. One reason for this is that the UK, like many other EU countries, is finding it difficult to comply with legally binding EU limit values for NO2 in outdoor air. Member States failing to comply face the possibility of large fines. This has re-focussed attention on the uncertainties in the evidence base underpinning the assessments of the possible impacts of NO2 on health.
The Health Protection Agency (HPA) and Department of Health (DH) recognised the important policy implications of these data gaps in preventing confident evaluation of the public health importance of ambient levels of NO2. In March 2011, DH’s Policy Research Programme commissioned a workshop, organised by the HPA, to consider this issue. The main aim of the workshop was to develop ideas for future research that would help disentangle the possible adverse health effects of NO2 from those of other pollutants. Proposals for different types of scientific investigation were then discussed and research recommendations agreed.
Presentations made during the workshop are made available for download.