Hatchfield, 2014: MINIMIZING DAMAGE IN STORAGE AND DISPLAY
Figure 1: Example of the blue color developed on prehistoric flints at the Museo Civico di Storia Naturale in Verona. Photograph
courtesy of the Soprintendenza ai Beni Archeologici del Veneto.
POLLUTANTS
Externally generated pollutants range widely
outdoors. For example, hydrogen sulfide levels
may measure as high as 5000 parts per trillion
A pollutant may be defined as an impurity in
(ppt) (7.03 g/m) in urban areas, but as low
the environment, derived either from natural or
as 50 ppt in remote areas. Between 1900 and
man-made sources. Pollutants are agents of
1970, nitrogen oxide emissions increased by an
deterioration that have the potential to interact
alarming
690%,
clearly
related
to
with materials of art in damaging ways. They
industrialization. Since 1970, most emissions
are reactive chemical compounds, which may
have decreased by about 40%, initially due to
be, in a gaseous, liquid or solid state. Liquids
the oil shortages of the 1970s, and increasing
may be also vapor based, or in aerosol form.
awareness about health and other dangers of
Semi-volatile pollutants such as plasticizers also
air pollution (Gradael et al., 1981, cited in
pose risks. Pollutants are generated in the
Hatchfield, 2002).
exterior environment, either from natural,
In interior spaces, construction materials,
biological sources, or by man-made, industrial
furnishings and combustion activities such as
processes and activities. The most common
burning fuel for heating generate most
pollutants in the environment include sulfurous
pollutants, and they often build up to very high
compounds, nitrogen oxides, ozone, ammonia,
levels in enclosed areas, being unable to
formaldehyde and acidic compounds. Some of
dissipate.
Sometimes,
collection
objects
these species may be damaging on their own,
themselves generate substances such as
or after interacting with atmospheric moisture
sulfur that are harmful to other specimens
to become acids or other harmful species.
or other objects. For
this
reason, it
is
93 Journal of Paleontological Techniques