from biomass burning. Large amounts of air pollution can be produced by the use
of fuelwood, widespread agricultural practices (e.g. burning of sugar cane
residues), the common practice of deforestation by burning, burning to renew
pastures and large-scale uncontrolled vegetation fires (e.g. the vegetation fire in
Roraima, in the Brazilian Amazon, in 1998).
Air pollution trends in Europe and North America. In Europe and North
America, the impacts of pollution by sulfur dioxide (SO
) and nitrogen oxides
(NO
V
) have led to agreements to reduce emissions of these gases. Consequently,
SO
emissions are declining in these regions and in 1995 were 48% lower in
Western Europe and 32% lower in North America compared with 1980 levels.
Emissions of NO
V
have stabilized and are reducing slightly in these regions with
1995 levels 16% lower in Europe and 6% lower in North America compared with
1989 levels (when NO
V
emissions peaked).
Assessing Air Pollution Impacts
Information on trends in emissions is useful, but limited, as it does not give a
comprehensive view of the potential changes in the impacts caused by air
pollution. For this reason, various methodologies have been developed to allow
assessments of the impacts associated with emission changes. The essential
ingredients are an atmospheric transfer model for the appropriate scale which
can use the emission estimates and model pollutant concentrations and
depositions and then, through an understanding of causal relationships, link
levels of pollution to impacts. There are essentially two ways in which this is
carried out: to use dose—response relationships or to use threshold values.
Concentration or deposition values can be used in combination with dose—response
relationships to estimate the magnitude of the response or can be used to show
when and where they exceed threshold values.
For health impacts at urban scale recent studies relating to the occurrence of
daily deaths (total and by cause) to daily changes in air pollution levels have
provided strong evidence of the health effects associated with particulate
pollution. A pooled estimate of major studies suggested that a 10 mg m\ increase
in PM
will be associated with an increase in daily mortality equal to 0.74%.
Similarly, an increase of 10 mg m\ in PM
levels will increase mortality by
1.5%. Using such information a recent estimate for Delhi suggests that an
annual reduction of 100 mg m\ in TSP could be associated with a reduction of
about 1400 premature deaths per year. Similar response information for ozone
exists, such as changes in emergency visits for asthma among children with
changes in 1-hour ozone concentrations. In addition to dose—response
UN-ECE, 1979 Convention on Long-range Transboundary Air Pollution and its Protocols.
ECE/EB.AIR/50, United Nations Economic Commission for Europe, Geneva, Switzerland, 1996.
I. Romieu and M. Hernandez, Air pollution and health in developing countries: review of
epidemiological evidence, in Health and Air Pollution in Developing Countries, ed. G. McGranahan
and F. Murray, Stockholm Environment Institute, York, 1999, pp. 43—56.
M. L. Cropper, N. B. Simon, A. Alberini and P. K. Sharma, The Health Effects of Air Pollution in
Delhi, India, The World Bank, PRD Working Paper 1860, 1997.
A Perspective on Global Air Pollution Problems
41
of fuelwood, widespread agricultural practices (e.g. burning of sugar cane
residues), the common practice of deforestation by burning, burning to renew
pastures and large-scale uncontrolled vegetation fires (e.g. the vegetation fire in
Roraima, in the Brazilian Amazon, in 1998).
Air pollution trends in Europe and North America. In Europe and North
America, the impacts of pollution by sulfur dioxide (SO
) and nitrogen oxides
(NO
V
) have led to agreements to reduce emissions of these gases. Consequently,
SO
emissions are declining in these regions and in 1995 were 48% lower in
Western Europe and 32% lower in North America compared with 1980 levels.
Emissions of NO
V
have stabilized and are reducing slightly in these regions with
1995 levels 16% lower in Europe and 6% lower in North America compared with
1989 levels (when NO
V
emissions peaked).
Assessing Air Pollution Impacts
Information on trends in emissions is useful, but limited, as it does not give a
comprehensive view of the potential changes in the impacts caused by air
pollution. For this reason, various methodologies have been developed to allow
assessments of the impacts associated with emission changes. The essential
ingredients are an atmospheric transfer model for the appropriate scale which
can use the emission estimates and model pollutant concentrations and
depositions and then, through an understanding of causal relationships, link
levels of pollution to impacts. There are essentially two ways in which this is
carried out: to use dose—response relationships or to use threshold values.
Concentration or deposition values can be used in combination with dose—response
relationships to estimate the magnitude of the response or can be used to show
when and where they exceed threshold values.
For health impacts at urban scale recent studies relating to the occurrence of
daily deaths (total and by cause) to daily changes in air pollution levels have
provided strong evidence of the health effects associated with particulate
pollution. A pooled estimate of major studies suggested that a 10 mg m\ increase
in PM
will be associated with an increase in daily mortality equal to 0.74%.
Similarly, an increase of 10 mg m\ in PM
levels will increase mortality by
1.5%. Using such information a recent estimate for Delhi suggests that an
annual reduction of 100 mg m\ in TSP could be associated with a reduction of
about 1400 premature deaths per year. Similar response information for ozone
exists, such as changes in emergency visits for asthma among children with
changes in 1-hour ozone concentrations. In addition to dose—response
UN-ECE, 1979 Convention on Long-range Transboundary Air Pollution and its Protocols.
ECE/EB.AIR/50, United Nations Economic Commission for Europe, Geneva, Switzerland, 1996.
I. Romieu and M. Hernandez, Air pollution and health in developing countries: review of
epidemiological evidence, in Health and Air Pollution in Developing Countries, ed. G. McGranahan
and F. Murray, Stockholm Environment Institute, York, 1999, pp. 43—56.
M. L. Cropper, N. B. Simon, A. Alberini and P. K. Sharma, The Health Effects of Air Pollution in
Delhi, India, The World Bank, PRD Working Paper 1860, 1997.
A Perspective on Global Air Pollution Problems
41