Scientists know mercury is emitted mostly from coal-burning power
plants, such as the one in Sugar Land, but there is additional mercury
coming from the area around the Houston Ship Channel and the nearby
refineries and petrochemical plants, according to the study. The more
than 100 scientists from UH and research institutions across the
country who pored over the air quality data are still analyzing the
information to identify what industrial processes are producing the
mercury.
Most of the data was collected from the UH Moody Tower Atmospheric
Chemistry Facility, an 18-story building that is operational 24 hours
a day, seven days a week, and from data collected from various
aircrafts and a National Oceanic Atmospheric Administration ship in
the Houston Ship Channel.
The Moody Tower facility measured three different types of mercury:
gaseous elemental mercury, reactive gaseous mercury and fine
particulate mercury. Although traces of mercury have been found all
over the country, the amounts detected varied from double to more than
six times what is typically found in other parts of the United States,
Lefer said.
�Mercury is toxic and is most detrimental to children and pregnant
women and causes developmental abnormalities,� Lefer said. �Mercury
emissions from coal and other sources are going to be more problematic
to reduce, but using cleaner fuels and alternative energy for
electricity will reduce the mercury levels in the environment.�
The base for embalming fluid, formaldehyde is believed to be the
catalyst in the production of ozone, a harmful pollutant that may be
primarily emitted from traffic and poorly maintained diesel cars, and
secondarily by chemical reactions in the atmosphere.
�Primary formaldehyde means it is directly emitted to the atmosphere,�
Rappenglueck said. �Secondary formaldehyde means that it is chemically
formed in the atmosphere from other chemicals.�
Formaldehyde emissions from automobile exhaust are directly emitted
into the atmosphere, but their contribution is small, Rappenglueck
said. Instead, the air quality data suggests there may be a �new�
source of primary formaldehyde emissions in Houston.
�Once the source of the formaldehyde is identified, it should be
possible to figure out how to reduce these emissions,� Lefer said.
�Formaldehyde is not toxic at these levels, but it is very efficient
at producing ozone pollution. We think this is one of the �missing�
links in understanding Houston�s ozone pollution.�
The UH Atmospheric Science group is working on calculations to assess
the impact of primary formaldehyde emissions in producing ozone in
Houston. They hope to have the results in time for conferences in
December and January.
The Texas Air Quality Study-II wasn�t all doom and gloom for Houston,
though. Houston does have a serious ozone problem, but efforts to fix
it are headed in the right direction.
�The bad news is that Houston�s ozone levels are above the
Environmental Protection Agency�s (EPA) standards for 30 to 40 days
each year,� Lefer said. �The EPA allows a city to have one to three
�bad� ozone days per year. So we are well above this average. But, the
good news is that the number of �bad� ozone days each year in Houston
is decreasing. In addition, the peak ozone values observed in Houston
have also been on a down trend the past six years. We still have a
long way to go, though.�
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