Monitoring of sulfuric acid episodes in St. Louis, Missouri
During July 1977 and again in February 1978 in St. Louis, Missouri, episodes of about 3-day duration occurred in which sulfuric acid persisted as part of the regional haze aerosol. These sulfuric acid episodes were monitored with 15-min time resolution by a thermal analysis--flame photometric detection particulate sulfur monitor. The measurement technique detects the concentration of total particulate sulfur as well as the fraction as H/sub 2/SO/sub 4/. However, it cannot distinguish between (NH/sub 4/)/sub 2/SO/sub 4/ and NH/sub 4/HSO/sub 4/; thus it is not specific for the detection of total hydrogen ion concentration associated with particulate sulfur. In the summer, July--August 1977, total particulate sulfur average was 3.8 ..mu..gS/m/sup 3/, and the H/sub 2/SO/sub 4/ (measured as sulfur) average was below 0.5 ..mu..gS/m/sup 3/, while in the winter, February--March 1978, it was 3.2 and 0.8 ..mu..gS/m/sup 3/, respectively. During the summer episode the H/sub 2/SO/sub 4/ (as sulfur) peaked at about 10 ..mu..gS/m/sup 3/, compared to a total particulate sulfur peak concentration of 20 ..mu..gS/m/sup 3/. During the winter episode the H/sub 2/SO/sub 4/ concentration peaked at about 4 ..mu..gS/m/sup 3/, compared to a particulate sulfur peak concentration of 6 ..mu..gS/m/sup 3/. Daily average particulate sulfur and light scattering from July--August 1977 and February--March 1978 show a strong correlation (r>0.8). There were several general differences between the summer and winter data which suggest chemical and physical changes in the atmospheric aerosol. Analysis of the summer data revealed overall diurnal patterns in particulate sulfur and acidity, but these patterns did not show up with the winter data. The strong correlation between light scattering and particulate sulfur indicates that sulfur compounds play a prominent role in visibility degradation by fine particles.
- Research Organization:
- Center for Air Pollution Impact and Trend Analysis, Washington Univeristy, St. Louis, Missouri 63130
- OSTI ID:
- 5132045
- Journal Information:
- J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 85:C8; ISSN JGREA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Contribution of fine-particle sulfates to light scattering in St. Louis
Meteorological factors affecting ambient concentration of acid aerosols
Related Subjects
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ACID RAIN
AEROSOLS
AIR POLLUTION MONITORS
ATMOSPHERIC PRECIPITATIONS
COLLOIDS
DISPERSIONS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
MIDWEST REGION
MISSOURI
NORTH AMERICA
PHOTOMETRY
RAIN
SOLS
SULFURIC ACID
USA