| Murali Adhikari |
Posted
on 16-Oct-00 11:33 AM
Report Delivers Good News, Bad News on Smog
WASHINGTON, DC, October 13, 2000 (ENS) - North American pollution
controls are working, but their full benefits are being offset by population growth,
energy demand and increased reliance on motor vehicles, according to a
comprehensive scientific report released Thursday.
Ground level ozone, or smog, is
caused when the pollutants in
motor vehicle exhaust react
with sunlight. (Photo courtesy Pacific
Northwest National Laboratory)
The North American Research
Strategy for Tropospheric Ozone
(NARSTO) said in its report that
reducing ground level ozone, or
smog, is possible despite these
factors. In Los Angeles, for
example, measurements show that
smog reductions have been
achieved despite continued growth
in the metropolitan area and growth
in number of vehicle miles traveled.
"Ozone concentrations at various
urban locations in North America do indeed show the benefits of the substantial
mitigative emission controls that began in the 1970s," said the NARSTO report.
"Nevertheless, in 1995 some 70 million people lived in or near U.S. counties
where ozone exceeded the standards; more than 13 million Canadians were
similarly located, and the same was true for 20 million of Mexico's population.
"Nonetheless, air quality would be considerably worse than it is today if these
emission controls were not in place," NARSTO continued.
NARSTO is a partnership of government, utilities, industry, and universities in
the United States, Canada and Mexico. It seeks to improve the atmospheric and
related sciences used to support air quality management policies.
Thursday's report entitled "An Assessment of Tropospheric Ozone Pollution: A
North American Perspective" is the first far reaching effort to address the status
of ozone reduction efforts since a 1991 U.S. National Research Council review.
Ozone is a natural constituent of the atmosphere, and is critical in the
stratosphere to protecting life on earth from the sun's harmful ultraviolet rays. But
closer to the ground and in the presence of sunlight, ozone reacts with nitrogen
oxides and volatile organic compounds and becomes a pollutant.
These two precursor gases are produced by natural sources such as forest fires
and by motor vehicles exhaust and industrial emissions. Ground level ozone can
damage human health and vegetation.
Truck on a highway near
Petersburg, West Virginia.
Yesterday's report
recommended more extensive
emissions monitoring in rural
areas since smog is not
confined to big cities. (Photo by
Ken Hammond, courtesy U.S. Department
of Agriculture)
NARSTO's report answered a
series of questions. For the
question, "Are existing emission
control measures helping to bring the ozone problem under control?" it answers,
"There is no single pattern for North American ozone trends. In the U.S., the
average daily maximum one hour ozone concentration decreased by about 15
percent over the decade 1986 to 1996.
"The largest downward trends have been found in Los Angeles, New York, and
Chicago. However, ozone trends show considerable differences from region to
region and some areas show upward trends.
"In Canada, there have been upward ozone trends in most of the more populated
regions: Vancouver, the Atlantic Provinces, and Ontario. Peak ozone
concentrations in Mexico City rose before 1990 but have leveled off since."
The report says that some of the differences in trends may result from country's
different approaches to emission controls. "Some differences could originate
from country specific methods used to establish trends," it added.
NARSTO called for the three countries' air quality monitoring networks to be
harmonized and a systematic network appraisal process set up. It said that a
central archive of air quality data would complement this process by stimulating
communities to manage air quality better.
Since smog is not confined to urban areas, the report recommended more
extensive monitoring in rural areas.
The report drew negative and positive conclusions. "On the optimistic side, one
can note that pollution controls have resulted in substantive improvements,
compared to the air quality that probably would exist in their absence," it said.
"Scientific understanding of ozone formation phenomena, the ability to
incorporate these features into modern computer models, the technology to
measure ozone precursors and their products reliably, and techniques for
quantitative estimation of both natural and human emissions all have advanced
markedly during the past 10 years.
"Properly linked with ozone management practices, these advances can be
expected to lead to significant improvements in future air quality in all of North
America.
"From a more pessimistic outlook, much of the potential for real air quality
improvement has been offset by expanding populations and human activity levels
in North America."
A meteorological tower with wind and
temperature sensors on a valley
sidewall near Dayton, Washington.
NARSTO's report said advances made in
meteorological research had helped
emissions monitoring. (Photo courtesy U.S.
Department of Agriculture)
Significant additional scientific
understanding will be required to develop
ozone management practices that provide
environmental protection at a reasonable
cost, added the report.
Linking science with those who make policy
decisions will be the most vital element of
further progress, it concluded. "Our real
progress during the next decade will depend
on the ability of these two communities to
interact closely and extensively in a
mutually productive fashion."
One such decision maker, Canada's Environment Minister David Anderson,
welcomed the report yesterday. "It is encouraging to know that pollution controls
have resulted in some air quality improvements, but our work has really just
begun," he said.
"This scientific information is important. It will help us develop technologies to
address the ground level ozone pollution problems we currently face."
To read the report, visit http://www.cgenv.com/Narsto/
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