Precipitation chemistry trends in the northeastern United States

Conference · Mon Jan 01 04:00:00 EST 1979

OSTI ID:6099151

Stensland, G J

Historical trends of the concentrations of the various trace substances in precipitation can serve as an indication of the changes in the levels of these substances in the air. Three topics related to the precipitation chemistry data base for the United States are examined. First, since the pH of precipitation is of major interest, techniques to calculate this quantity are considered. Next, the changes in the precipitation chemistry for a central Illinois site are discussed. This site is at the western edge of present high atmospheric sulfate levels, and thus it is interesting to examine changes in the precipitation pH at this site and the reasons for them. Changes in the sulfate and nitrate at this central Illinois site and other sites further East are also discussed, and these changes are compared to the time trends in the anthropogenic source emissions. Results suggest that at present the best approach to calculating the pH of a precipitation sample is to assume that a charge balance exists and then to apply an empirical correction. With this approach the 1977 central Illinois samples are shown to be much more acid than those from 1954. The primary reason for this pH decrease is the decreased concentration of calcium and magnesium in the samples. For the mid-1970's compared to the mid-1950's the source emissions estimates for the United States were up by a factor of 1.3 for sulfur and 2.1 for nitrogen. During this same time interval the sulfate concentrations for the precipitation chemistry sites in the northeastern United States remained about the same and the nitrate concentrations increased by factors varying from 1.3 to 1.8. Since the emissions estimates increased more than the precipitation concentrations, it would seem that a smaller fraction of the pollutants were being removed over the northeast by wet processes in the mid-1970's than in the mid-1950's.

• Research Organization: Illinois State Water Survey, Urbana (USA)
• DOE Contract Number: EY-76-S-02-1199
• OSTI ID: 6099151
• Report Number(s): COO-1199-55; CONF-790573-2
• Country of Publication: United States
• Language: English

Related Subjects

500200* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ACID CARBONATES
AIR POLLUTION
ALKALI METALS
ALKALINE EARTH METALS
AMMONIUM COMPOUNDS
ATMOSPHERIC PRECIPITATIONS
CALCIUM
CHEMICAL COMPOSITION
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
DATA
DATA COMPILATION
DATA FORMS
ELEMENTS
GRAPHS
GREAT LAKES REGION
HALIDES
HALOGEN COMPOUNDS
ILLINOIS
INFORMATION
MAGNESIUM
METALS
MONITORING
NITRATES
NITROGEN COMPOUNDS
NORTH AMERICA
NUMERICAL DATA
OXYGEN COMPOUNDS
PH VALUE
POLLUTION
POTASSIUM
SODIUM
SULFATES
SULFUR COMPOUNDS
TABLES
USA