The potential role of background ozone on current and emerging air issues: An overview

摘要

It is now widely recognized that background ozone may form a significant part of the concentration and, thus, of the health and ecosystem impacts, experienced at many locations. This can be extremely important, as the background concentration is the level below which concentrations cannot be reduced by local efforts alone. In discussing background ozone, it is important to be clear what is meant by the term. Slightly different interpretations of the exact understanding of what constitutes background widen the uncertainty in reported values. Nevertheless, the central tendency to reported background ozone concentrations may be estimated as 25 to 40 ppb for measurements made worldwide. The large majority of recently reported work indicates that these background concentrations are increasing at a rate ranging up to about 0.3 to 0.5 ppb per year. Ozone lifted to levels above the boundary layer can be transported very long (intercontinental) distances. As a result, Asia, North America, and Europe can all contribute to each other’s background ozone concentrations. In this context, the rapid industrial growth in Asia and the expected accompanying increased precursor emissions, could prove to be significant.