Page 425 - Fundamentals of Air Pollution 3E

V. Air Quality Standards 377

and the loss suffered by the segments of local industry and commerce
that are dependent on farm crops and the farmer for their existence. An
interesting sidelight is that when such damage occurs on the periphery of
an urban area, it is frequently a precursor to the breakup of such farmland
into residential development, with a financial gain rather than a loss to the
landowner. When the crop that disappears is an orchard, grove, or vineyard
that took years to establish, and when usable farm buildings are torn down,
society as a whole suffers a loss to the extent that it will take much time
and money to establish a replacement for them at new locations. To some
industries, air pollution costs include purchase of farm and ranch land to
prevent litigation to recover damages, annual subsidy payments to farmers
and ranchers in lieu of such litigation, and maintenance of air quality
monitoring systems to protect themselves against unwarranted litigation
for this purpose.
There is a range of ambiguity in our human health effects criteria data,
In this range there is disagreement among experts as to its validity and
interpretation. Thus, from the same body of health effects data, one could
adopt an air quality standard on the high side of the range of ambiguity
or one on the low side. Much soul searching is required before one accepts
the results of questionable human health effects research and is accused
of imposing large costs on the public by so doing, or of rejecting these
results and being accused of subjecting the public to potential damage of
human health.

V. AIR QUALITY STANDARDS

Since air pollution is controlled by air quality and emission standards,
the principal philosophical discussions in the field of air pollution control
focus on their development and application.
The U.S. Clean Air Amendments of 1977 define two kinds of air quality
standards: primary standards, levels that will protect health but not neces-
sarily prevent the other adverse effects of air pollution, and secondary
standards, levels that will prevent all the other adverse effects of air pollu-
tion (Table 22-7). The amendments also define air quality levels that cannot
be exceeded in specified geographic areas for "prevention of significant
deterioration" (PSD) of the air of those areas. Although they are called
"increments" over "baseline air quality" in the law, they are in effect tertiary
standards, which are set at lower ambient levels than either the primary
or secondary standards (Table 22-8).
Increments are said to be "consumed" as new sources are given permits
that allow pollution to be introduced into these areas. Jurisdictions with
authority to issue permits may choose to "allocate" portions of a PSD
increment (or of the difference between actual air quality and the primary