Historic Stone Building in Downtown Philadelphia
Scientists studying the degradation rates of stone materials outdoors measure and model natural and
pollution-related degradation processes and their effects on buildings such as this one (Figure 7a).
Notice that the structural features in Figure 7b are much sharper than those in Figure 7c, which are
more rounded due to degraded edges. These types of studies require measuring the wet and dry deposition
of natural and pollutant chemicals. Meteorological variables such as solar radiation, temperature,
relative humidity and condensation of moisture, measured with inches of the
surfaces shown in Figures 7b and 7c, are also important in understanding
the rates at which surfaces degrade outdoors.
Click on a photo to view a larger version.
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Fig7a. |
