The objectives of the study have been to investigate the uptake of air poll
utants (SO2, NO2 and O-3), especially synergistic effects when these pollut
ants are present together, and the effects of climate.
The initial dry deposition of the pollutants onto a paper surface was studi
ed using on-line gas analysis. The paper samples were exposed to synthetic
atmospheres with careful control of pollutant concentrations, relative humi
dity and now conditions.
The depositions of NO2 and O-2 were judged to be insignificant in the prese
nt study. The investigated papers showed a low tendency to pick up SO2 alon
e. The deposition of SO2 was however enhanced by the presence of the other
pollutants, and also by a high relative humidity. The addition of NO2 incre
ased the pick-up of SO2 at high relative humidities, while the addition of
O-3 also increased the pick-up of SO2 at intermediate humidities.
The presence of CaCO3 favoured a high pick-up of SO2 on the alkaline papers
However, ii was found that the alkaline papers responded differently to SO
2. This may indicate that the alkali reserve under adverse conditions is ei
ther too rapidly consumed or passivated, probably due to the paper manufact
uring process and the origin of the filler.