Recommendation for an Air Quality Standard for Nitrogen Dioxide

30. The Panel recommend an Air Quality Standard for nitrogen dioxide in the United Kingdom of 150 ppb measured as an hourly average.
31. The Panel consider that a longer-term Standard is also desirable, but believe that there is as yet insufficient evidence from which to determine an appropriate value. We recommend that this be reconsidered within the next three years and, in the meantime, also recommend a strategy of reduction in the annual average concentration of nitrogen dioxide.
32. These recommendations taken together are intended to reduce the levels of exposure of the population to concentrations in the outdoor air at which acute health effects will be extremely uncommon in susceptible people and at which more subtle effects on the public health will become progressively more difficult to detect. It is intended that techniques for monitoring the Standard should be consistent with the measurements made by the Department of the Environment in its national automatic nitrogen dioxide monitoring networks.