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Big Bend Regional Sierra Club
Regular Public Meeting
15 October 2002

Chair Don Dowdey called the meeting to order at 7:00 p.m. in 309, Lawrence Hall, Sul Ross State University, with ~37 in attendance.


  • The Lone Star Chapter of the Sierra Club will hold its 13th biennial State Legislative Workshop on 16 November 2002 in Austin at St. Edward’s University. The workshop will focus on preparing Sierra Club members for the upcoming legislative session. Then on 17 November 2002, the day following the legislative workshop, the Lone Star Chapter will host the second Beyond Nuclear Power Conference somewhere in Austin near the capitol. BBRSC members are encouraged to attend.
  • Treasurer Ginny Campbell is coordinating Sierra Club calendar sales again this year. Wall calendars are $11.95 and datebook calendars are $12.95. All members are urged to buy calendars for personal use and for gifts, and also to take a few to sell. Last year, calendar sales proved to be a significant money raiser for BBRSC.
  • The next regular public meeting will be 19 November 2002, when Representative Pete Gallego will speak on the upcoming legislative session.


Dr. Matthew Shetrone, Lead Resident Astronomer for the Hobby-Eberly Telescope at McDonald Observatory, spoke on a systematic scientific investigation he has undertaken to assess any impact air pollution may be having in the region around the observatory. Matthew has been using visual observations, the weather archive at McDonald Observatory, and particle counter/monitor data in his study. He has found no correlation between particles >0.3 microns and >1.0 microns, suggesting that regional haze is a complex situation. Days exhibiting high haze values based on visual observations have high particle counts as well, and are associated with southeasterly winds. Matthew found that the flux of Altair is low with high particle counts, by a factor of two. This means that regional haze does have a negative effect on astronomy by dimming and scattering light.

What is the composition of the detected particles? Based on analysis of a dataset from samples taken at Sul Ross State University:

Wind NOT blowing from SERatio with SE wind
Organic Carbon25%1.1

Thus, levels of sulfate, sulfur, and ammonium increase significantly with southeasterly winds. Sulfur gasses are hazardous byproducts of burning carbon. High sulfate concentrations are associated with high small particle counts.

In conclusion:

  1. Haze near McDonald Observatory comes from the southeast (Carbon I & II and the gulf region).
  2. Southeasterly haze is associated with increased concentrations of sulfur and sulfate.
  3. Haze reduces visibility on the horizon by a factor of 2.
  4. Haze reduces astronomical throughput by a factor of 1.3 to 2.

During a question and answer session following the presentation, Fran Sage reminded us that, according to NPS and EPA, Carbon I & II represent the single greatest source of air pollution in our region but do not account for the majority. Matthew mentioned that the trace elements bromine and strontium may increase during "emergency" releases from power plants. Also, in response to a question from Doug McCombs, Matthew explained that reflectivity of the Hobby-Eberly Telescope mirrors was measured at 98% when installed, however it is now down to 68%. It is not know to what extent regional haze and air pollution may have contributed to this decline.

Business Meeting:

  • Don reports that if we gain four more memberships, BBRSC will no longer be the smallest Sierra Club chapter in the state.
  • Ginny Campbell presented the treasurer’s report. Available funds as of October 15 total $1155.14.
  • The minutes of the September meeting were distributed and motion passed to accept.
  • Meeting adjourned with refreshments.

Submitted by Linda Hedges, Secretary


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