Page 424 - Fundamentals of Air Pollution 3E

376 22. Air Quality Criteria and Standards

or one with restricted scenic views. However, these costs are less likely to
be involved in deciding, for air quality standard-setting purposes, how
much of the attainable visibility improvement to aim for than are aesthetic
considerations. Just as in the previously noted case of soiling, judgment
on the limit of public tolerance for visibility reduction still has to be related to
the pollutant loading of the atmosphere that will yield the desired visibility.
Obviously, the pollutant level chosen for an air quality standards must be
the lower of the values required for soiling or visibility, otherwise one will
be achieved without the other. Whether the level chosen will not be lower
than the atmospheric pollutant level required for prevention of health ef-
fects will depend on the aesthetic standards of the jurisdiction.

IV. CONVERSION OF BIOLOGICAL DATA AND
CRITERIA TO STANDARDS

There is considerable species variability with respect to damage to vegeta-
tion by any specific pollutant. There is also great geographic variability
with respect to where these species grow naturally or are cultivated. Because
of this, it is possible that in a jurisdiction none of the species particularly
susceptible to damage by low levels of pollution may be among those
indigenous or normally imported for local cultivation. As an example, the
pollution level at which citrus trees are adversely affected, while meaningful
in setting air quality standards in California and Florida, is meaningless
for this purpose in Minnesota and Wisconsin. In like manner, a jurisdiction
may take different viewpoints with respect to indigenous and imported
species. It might set its air quality standards low enough to protect its
indigenous vegetation even if this level is too high to allow satisfactory
growth of imported species. Even if a particularly susceptible species is
indigenous, it may be held in such low local esteem commercially or aesthet-
ically that the jurisdiction may be unwilling to let the damage level of that
species be the air quality standard discriminator. In other words, the people
would rather have that species damaged than assume the cost of cleaning
up the air to prevent the damage. This same line of reasoning applies to
effects on wild and domestic animals.
A jurisdiction may base part of its decision making regarding vegetation
and animal damage on aesthetics. Its citizens may wish to grow certain
ornamentals or raise certain species of pet birds or animals and allow these
wishes to override the agricultural, forestry, and husbandry economics of
the situation. Usually, however, economic considerations predominate in
decision making. Costs of air pollution effects on agriculture are the sum
of the loss in income from the sale of crops or livestock and the added cost
necessary to raise the crops or livestock for sale. To these costs must be
added the loss in value of agricultural land as its income potential decreases