Environment, pollution and effects.

This chapter will look at the main environmental influences and controls on damage to heritage, which occurs even in the absence of pollution, and also examine the main characteristics and sources of the most important air pollutants that exacerbate this damage or, in some cases, add new types of damage. The types of damage are briefly reviewed at the beginning of the chapter. It is also important to understand the environmental factors that not only influence weathering in the absence of pollution but also are key to the control of pollution damage, and so these are also briefly reviewed.