Page 420 - Fundamentals of Air Pollution 3E

372 22. Air Quality Criteria and Standards

TABLE 22-4
U.S. Air Quality Criteria for Nitrogen Dioxide
Concentration of
nitrogen dioxide in Exposure Human symptoms and effects on
air (ppm) time vegetation, materials, and visibility
300 _ Rapid death
150 — Death after 2 or 3 weeks by bronchiolitis fibrosa obliterans
50 — Reversible, nonfatal bronchiolitis
10 — Impairment of ability to detect odor of nitrogen dioxide
5 15 min Impairment of normal transport of gases between the blood
and lungs in healthy adults
2,5 2hr Increased airway resistance in healthy adults
2 4hr Foliar injury to vegetation
1.0 15 min Increased airway resistance in bronchitics
1.0 48 hr Slight leaf spotting of pinto bean, endive, and cotton
_
0.3 Brownish color of target 1 km distant
0.25 Growing Decrease of growth and yield of tomatoes and oranges
season
0.2 8hr Yellowing of white fabrics
0.12 — Odor perception threshold of nitrogen dioxide
0.1 12 weeks Fading of dyes on nylon
0.1 20 weeks Reduction in growth of Kentucky bluegrass
0.05 12 weeks Fading of dyes on cotton and rayon
0.03 _ Brownish color of target 10 km distant
0.003 Brownish color of target 100 km distant
—
Sources: Draft Air Quality Criteria for Oxides of Nitrogen, U.S. Environmental Protection
Agency, Research Triangle Park, NC, 1981; Review of the National Ambient Air Quality
Standard for Nitrogen Dioxide, Assessment of Scientific and Technical Information, EPA-450/
5-82-002. U.S. Environmental Protection Agency, Research Triangle Park, NC, March 1982.

rial in the blood, tissue, bone, or teeth, part or all of the buildup could be
from ingestion of food or water containing the material. Diseases which
are respiratory can be caused by smoking or occupational exposure. They
may be of a bacterial, viral, or fungal origin quite divorced from the inhala-
tion of human-made pollutants in the ambient air. These causes in addition
to the variety of congenital, degenerative, nutritional, and psychosomatic
causes of disease must all be ruled out before a disease can be attributed
to air pollution. However, air pollution commonly exacerbates preexisting
disease states. In human health, air pollution can be the "straw that breaks
the camel's back."
Air quality standards prescribe pollutant levels that cannot legally be
exceeded during a specific time period in a specific geographic area. Air
quality standards are based on air quality criteria, with added safety factors
as desired.