This stresses the direct relationship between particulate matter concentrations
and visibility. According to Maddison, visibility range in Europe is a ‘good’
that has significant economic value, although little attention to such valuation
has occurred in Europe. Visibility can never really be separated from the aesthetic
qualities of the landscape, which casts doubt on the transferability of valuation
exercises. However, many developing countries rely on visibility for tourism. In
Nepal, atmospheric visibility data indicate that there has been a substantial
decrease in visibility in the Kathmandu Valley since 1970. The number of days
with good visibility in Winter at Kathmandu Airport has decreased from 25 days
per month in 1972 to 5 days per month in 1992. The bowl-like topography and
low wind speeds during the winter season create poor dispersion conditions,
predisposing the Kathmandu Valley to serious air pollution problems (World
Bank). A pessimistic, but accurate image of the air pollution situation in the
Kathmandu Valley gave negative publicity to the area that could have had an
adverse impact on tourism. In the early 1990s, foreign currency revenues
amounted to approximately US$60 million a year. Although no ‘dose—effect’
relationships of air pollution and tourism are available, if it were assumed that
there could be approximately 10% decrease in tourism, then this could lead to a
loss of to US$6 million for Nepal. This is a very significant amount of foreign
exchange for a country that has a negative balance of trade.
Regional Air Pollution
Gaseous emissions such as sulfur dioxide and nitrogen oxides are rapidly
oxidized to sulfate and nitrate, and ammonia is transformed to ammonium in the
atmosphere. These pollutants can travel over very long distances, transported by
the winds over hundreds of kilometres and then deposited by wet deposition in
rain, occult (in cloud) deposition and dry deposition to surfaces and may cause
impacts far from the source of pollution. Sulfur and nitrogen deposition may
acidify ecosystems and nitrogen may be responsible for eutrophication
(over-fertilization) of terrestrial ecosystems. Ozone is another gas which, once
produced, may be transported over long distances and have effects on vegetation.
Acidification, to a lesser extent eutrophication, and more recently ozone impacts
on crops and forests are impacts that have led to the development of negotiations
between countries in Europe and elsewhere that are receiving each others’
pollution. The need for such negotiations becomes clear when one considers that
more than 90% of the acidic deposition in Norway (where acidification of lakes
has been a large problem) came from sources outside Norway during the early
1980s (EMEP model calculations) when the negotiations were gaining
momentum.
D. Maddison, The Economic Value of Visibility: A Survey, Centre for Social and Economic
Research on the Global Environment (CSERGE), University College, London and University of
East Anglia, 1997.
UNEP, State of the Environment: Nepal, United Nations Environment Programme, Regional
Resource Centre for the Asia-Pacific. Pathumthani, Thailand, 2001.
Article in Newsweek, October 1993.
J. Lehmhaus, J. Saltbones and A. Eliassen, Deposition Patterns and Transport Sector Analyses for a
Four-Year Period, EMEP/MSC-W Report 1/85, The Norwegian Meteorological Institute, Oslo, 1985.
J. C. I. Kuylenstierna, W. K. Hicks and M. J. Chadwick
34
and visibility. According to Maddison, visibility range in Europe is a ‘good’
that has significant economic value, although little attention to such valuation
has occurred in Europe. Visibility can never really be separated from the aesthetic
qualities of the landscape, which casts doubt on the transferability of valuation
exercises. However, many developing countries rely on visibility for tourism. In
Nepal, atmospheric visibility data indicate that there has been a substantial
decrease in visibility in the Kathmandu Valley since 1970. The number of days
with good visibility in Winter at Kathmandu Airport has decreased from 25 days
per month in 1972 to 5 days per month in 1992. The bowl-like topography and
low wind speeds during the winter season create poor dispersion conditions,
predisposing the Kathmandu Valley to serious air pollution problems (World
Bank). A pessimistic, but accurate image of the air pollution situation in the
Kathmandu Valley gave negative publicity to the area that could have had an
adverse impact on tourism. In the early 1990s, foreign currency revenues
amounted to approximately US$60 million a year. Although no ‘dose—effect’
relationships of air pollution and tourism are available, if it were assumed that
there could be approximately 10% decrease in tourism, then this could lead to a
loss of to US$6 million for Nepal. This is a very significant amount of foreign
exchange for a country that has a negative balance of trade.
Regional Air Pollution
Gaseous emissions such as sulfur dioxide and nitrogen oxides are rapidly
oxidized to sulfate and nitrate, and ammonia is transformed to ammonium in the
atmosphere. These pollutants can travel over very long distances, transported by
the winds over hundreds of kilometres and then deposited by wet deposition in
rain, occult (in cloud) deposition and dry deposition to surfaces and may cause
impacts far from the source of pollution. Sulfur and nitrogen deposition may
acidify ecosystems and nitrogen may be responsible for eutrophication
(over-fertilization) of terrestrial ecosystems. Ozone is another gas which, once
produced, may be transported over long distances and have effects on vegetation.
Acidification, to a lesser extent eutrophication, and more recently ozone impacts
on crops and forests are impacts that have led to the development of negotiations
between countries in Europe and elsewhere that are receiving each others’
pollution. The need for such negotiations becomes clear when one considers that
more than 90% of the acidic deposition in Norway (where acidification of lakes
has been a large problem) came from sources outside Norway during the early
1980s (EMEP model calculations) when the negotiations were gaining
momentum.
D. Maddison, The Economic Value of Visibility: A Survey, Centre for Social and Economic
Research on the Global Environment (CSERGE), University College, London and University of
East Anglia, 1997.
UNEP, State of the Environment: Nepal, United Nations Environment Programme, Regional
Resource Centre for the Asia-Pacific. Pathumthani, Thailand, 2001.
Article in Newsweek, October 1993.
J. Lehmhaus, J. Saltbones and A. Eliassen, Deposition Patterns and Transport Sector Analyses for a
Four-Year Period, EMEP/MSC-W Report 1/85, The Norwegian Meteorological Institute, Oslo, 1985.
J. C. I. Kuylenstierna, W. K. Hicks and M. J. Chadwick
34