166
(GHGEs), such as N 2 O and CH 4 , intensifies the heat radiation absorption of
the earth’s atmosphere resulting to increasing surface temperatures. It is
expressed in terms of mass (e.g., kgCO 2 equivalents).
• Ozone depletion potential: the thinning of the ozone layer in the stratosphere
due to emissions from human activities which causes a potential damage to
human health, ecosystems, biochemical cycles, and materials. It is described
as the ratio between the amount of ozone destroyed by a unit of a substance
and a reference substance, which is usually Trichlorofluoromethane (CFC11). It is expressed in kg-CFC-11 equivalents.
• Acidification potential: the acidity of water and soil systems can be increased
due to acid deposition from the atmosphere, mainly in the form of rain.
Sulfur dioxide (SO 2 ), ammonia (NH 3 ) released through volatilization, and
nitrogen oxides (NOx) emitted by combustion processes (such as burning
rice straw) causes “acid rain.” It is expressed in kg-SO 2 equivalents.
(c) Water Pollution
• Eutrophication potential: the increase of the concentration of nutrients,
chiefly nitrogen (N) and phosphorus (P), in a body of water caused by the
runoff of synthetic fertilizers from agricultural land or by the input of sewage
or animal waste. It causes the reduction in species diversity and the overpopulation of a dominant species, which is usually algae—a phenomenon
called “algal bloom”. In turn, the increased production of dead biomass from
algae consumes oxygen thru a degradation process, and depletes the oxygen
in the water. It is expressed in phosphate (PO 4
3−
) equivalents.
• Aquatic ecotoxicity: the impact on fresh water ecosystems as a result of
emissions of toxic substances into air, water, and soil. It is expressed as
1,4-dichlorobenzene equivalents (1,4 DB-eq) per kg of emission.
(d) Soil Pollution
• Terrestrial ecotoxicity: the impact of toxic substances released into terrestrial ecosystems. It is defined as the potential of terrestrial toxicity of each
substance emitted into the air, water, and/or soil and expressed as 1,4 DB-eq
per kg of emission.
(e) Damage, Health, and Biodiversity
• Human toxicity potential: the impact on human health of toxic substances
present in the environment. Human toxicity is identified as the overall impact
of toxic substances into air, water, and soil, which are most vulnerable to pollution and contamination, such as carbon monoxide (CO), black carbon from
straw burning, heavy metal loads in water and soil, etc. These toxic substances
accumulate in the vegetables, fruits, meat, milk and other animal products
which in turn are ingested by humans. It is expressed in kg of 1,4 DB-eq.
• Disability-adjusted life years (DALY): It is the total years of life lost by premature mortality and the lost of productive life due to incapacity (Goedkoop
and Spriensma 2001). This indicator, expressed in DALY kg
−1
of emission,
determines amounts of heavy metals and carcinogenic substances.
N. V. Hung et al.
(GHGEs), such as N 2 O and CH 4 , intensifies the heat radiation absorption of
the earth’s atmosphere resulting to increasing surface temperatures. It is
expressed in terms of mass (e.g., kgCO 2 equivalents).
• Ozone depletion potential: the thinning of the ozone layer in the stratosphere
due to emissions from human activities which causes a potential damage to
human health, ecosystems, biochemical cycles, and materials. It is described
as the ratio between the amount of ozone destroyed by a unit of a substance
and a reference substance, which is usually Trichlorofluoromethane (CFC11). It is expressed in kg-CFC-11 equivalents.
• Acidification potential: the acidity of water and soil systems can be increased
due to acid deposition from the atmosphere, mainly in the form of rain.
Sulfur dioxide (SO 2 ), ammonia (NH 3 ) released through volatilization, and
nitrogen oxides (NOx) emitted by combustion processes (such as burning
rice straw) causes “acid rain.” It is expressed in kg-SO 2 equivalents.
(c) Water Pollution
• Eutrophication potential: the increase of the concentration of nutrients,
chiefly nitrogen (N) and phosphorus (P), in a body of water caused by the
runoff of synthetic fertilizers from agricultural land or by the input of sewage
or animal waste. It causes the reduction in species diversity and the overpopulation of a dominant species, which is usually algae—a phenomenon
called “algal bloom”. In turn, the increased production of dead biomass from
algae consumes oxygen thru a degradation process, and depletes the oxygen
in the water. It is expressed in phosphate (PO 4
3−
) equivalents.
• Aquatic ecotoxicity: the impact on fresh water ecosystems as a result of
emissions of toxic substances into air, water, and soil. It is expressed as
1,4-dichlorobenzene equivalents (1,4 DB-eq) per kg of emission.
(d) Soil Pollution
• Terrestrial ecotoxicity: the impact of toxic substances released into terrestrial ecosystems. It is defined as the potential of terrestrial toxicity of each
substance emitted into the air, water, and/or soil and expressed as 1,4 DB-eq
per kg of emission.
(e) Damage, Health, and Biodiversity
• Human toxicity potential: the impact on human health of toxic substances
present in the environment. Human toxicity is identified as the overall impact
of toxic substances into air, water, and soil, which are most vulnerable to pollution and contamination, such as carbon monoxide (CO), black carbon from
straw burning, heavy metal loads in water and soil, etc. These toxic substances
accumulate in the vegetables, fruits, meat, milk and other animal products
which in turn are ingested by humans. It is expressed in kg of 1,4 DB-eq.
• Disability-adjusted life years (DALY): It is the total years of life lost by premature mortality and the lost of productive life due to incapacity (Goedkoop
and Spriensma 2001). This indicator, expressed in DALY kg
−1
of emission,
determines amounts of heavy metals and carcinogenic substances.
N. V. Hung et al.