The greatest damage is caused by sulphur dioxide, which is corrosive in both gaseous form and when converted into sulphuric acid. Nitrogen oxides also contribute to the damage, partly through the formation of corrosive nitric acid, and partly by reinforcing the damaging effects of sulphur dioxide. Ozone and other oxidants react readily with organic substances. They contribute mainly to the breakdown of textiles, leather and rubber. As a result of its oxidizing ability ozone can also increase the corrosiveness of compounds of sulphur and nitrogen oxides.
Dry fallout is considered to do more damage than wet, since it can dissolve in the film of condensation on various surfaces and remain there for a long time. This can lead to
high concentrations that are highly corrosive, since the pollutant is dissolved in such a small quantity of water. It also means that the pollutant can be “reused" as long as it remains there. It may dry out in the meantime, but can go back into solution whenever the surface becomes moist, with dew for example. Rain on the other hand, even if it is acidic, washes the pollutants away.
Source: Air and the environment by P.Elvingson and C.Ågren
Guidance on GAINS application (pdf, 2.4 MB) model in the state environmental management system of the Russian Federation (Russian; English version is under development)
Guidance document on Critical Load assessments (in Russian) (pdf, 790.3 kB)