Local and global impacts

For example, conditions of low wind speed coupled to a ‘temperature inversion’ where vertical mixing of the atmosphere does not occur.

Contribution to global impacts is more difficult to relate to the materials emitted from your site. Some pollutants escape into the higher regions of the atmosphere and disperse over thousands of miles before their impact occurs, e.g. dispersion of ozone depleting substances to the polar regions where they react with stratospheric ozone.

There is also the contribution of CO₂ and other gases, as products of combustion, to climate change and acid rain, for example.

Assessing the environmental impacts of some of these problems is important in order to decide on the relative importance (see definition of Aspects and Impacts in environmental management systems).

In assessing the effects of the pollution, weather and wind direction need to be taken into account. For example, the environmental health impacts of emissions into a populated area or next to a hospital or school must be considered.