pulp and paper mills, forestry product plants, coal
processing plants, and the metal industry [42, 44].
Ammonia is another atmospheric reduced gas,
and like VOCs its ultimate source can be biological; in addition, large amounts are made in the
Haber-Bosch process for use as fertilizer. Ammonia is the most common reduced nitrogen species
in the air. Ammonia is a corrosive and poisonous
gas and is mainly emitted from agriculture
[51]. It’s emitted from manure storage, slurry
spreading, and the use of fertilizers. It is a major
contributor to fixed nitrogen in the environment.
NH 3 deposits in soil, in water, and on vegetation.
In excess, nutrient nitrogen can lead to eutrophication causing severe damage to the aquatic and
terrestrial environments. It can also decrease the
pH level of soil and water resulting in acidification
and biodiversity loss [18]. Moreover, recent studies show that ammonia contributes significantly to
the production of regional particulate matter by
reacting with airborne acids, yielding particle
nuclei [52, 53].
Secondary Organic Aerosols (SOAs)
VOCs are important precursors of secondary
organic aerosols. In a study [54] in Beijing, continuous hourly measurements of VOC were
conducted to investigate the SOA formation
potential and the factors contributing to VOC
during hazy episodes. Photochemical oxidation
of VOC fuel, catalyzed by HOx and NOx radicals,
produces SOA and ozone in the troposphere
[7]. During the hazy events, the concentration of
VOCs was elevated providing both correlation
and mechanism. Aromatic compounds were
found to be the dominant contributor to the SOA
formation potential followed by alkenes and
alkanes. The source profile showed that the second highest VOC emissions came from industry.
In conclusion, the photochemical reactions of
VOC are the main reason for hazy events due to
the production of SOA and ozone by the reactions
of aromatic compounds with OH radicals.
Heavy Metals
Heavy metals are common air pollutants, and their
long-range transport has a great impact on the
ecosystem and human health. Although heavy
metals are usually present in ambient air at low
levels, their deposition in soils and water leads to a
buildup in the environment. Due to their properties, heavy metals are very persistent and are not
easily bound or deactivated in the environment.
This, combined with their toxicity, can result in
serious adverse health effect even at low concentration exposures [55]. Many heavy metals are
accumulated in soils and taken up by plants.
Some of them can be transferred from one organism to the other and biomagnified in animals at the
top of the food chain. Oral exposure is the main
route for human exposure to heavy metals. Ingestion of contaminated food and water, in comparison with rather low concentrations of heavy
metals in the ambient air, typically has much
more severe adverse effects. Even small emissions
of heavy metals into atmosphere result in their
deposition into soil. Uptake by plants leads to
contamination of the food chain. Therefore, it is
crucial to control atmospheric emissions in order
to decrease deposition and reduce heavy metal
intake by humans [18]. The assessment of metal
and metalloid compounds in ambient air is complicated due to different properties of existing
species and their reactivity, toxicity, and carcinogenic potential. Hence a good understanding of
different species and their sources is crucial for
proper evaluation of adverse health effects.
The compounds can be characterized using
parameters such as water solubility, particle size
distribution, specific surface area, etc. The parameters will play an important role in their toxicity
and bioavailability [55]. Metal in ambient air is
encountered mainly as a component of particulate
matter. EU air quality standards measure heavy
metals according to their concentration in PM 10 .
However, due to its relatively larger surface area
and its longevity in the atmosphere, fine PM can
have a larger effect on the health impact [56]. Furthermore, fine particles are transported much farther in the atmosphere and affect even the most
remote regions, in contrast to coarse particles
which due to their mass are usually deposited
near the source. The size of a particle will also
determine its deposition in living organisms and
how deeply can they penetrate the respiratory
system and which organs are affected [55].
Industrial Emissions Control Technologies: Introduction
481
processing plants, and the metal industry [42, 44].
Ammonia is another atmospheric reduced gas,
and like VOCs its ultimate source can be biological; in addition, large amounts are made in the
Haber-Bosch process for use as fertilizer. Ammonia is the most common reduced nitrogen species
in the air. Ammonia is a corrosive and poisonous
gas and is mainly emitted from agriculture
[51]. It’s emitted from manure storage, slurry
spreading, and the use of fertilizers. It is a major
contributor to fixed nitrogen in the environment.
NH 3 deposits in soil, in water, and on vegetation.
In excess, nutrient nitrogen can lead to eutrophication causing severe damage to the aquatic and
terrestrial environments. It can also decrease the
pH level of soil and water resulting in acidification
and biodiversity loss [18]. Moreover, recent studies show that ammonia contributes significantly to
the production of regional particulate matter by
reacting with airborne acids, yielding particle
nuclei [52, 53].
Secondary Organic Aerosols (SOAs)
VOCs are important precursors of secondary
organic aerosols. In a study [54] in Beijing, continuous hourly measurements of VOC were
conducted to investigate the SOA formation
potential and the factors contributing to VOC
during hazy episodes. Photochemical oxidation
of VOC fuel, catalyzed by HOx and NOx radicals,
produces SOA and ozone in the troposphere
[7]. During the hazy events, the concentration of
VOCs was elevated providing both correlation
and mechanism. Aromatic compounds were
found to be the dominant contributor to the SOA
formation potential followed by alkenes and
alkanes. The source profile showed that the second highest VOC emissions came from industry.
In conclusion, the photochemical reactions of
VOC are the main reason for hazy events due to
the production of SOA and ozone by the reactions
of aromatic compounds with OH radicals.
Heavy Metals
Heavy metals are common air pollutants, and their
long-range transport has a great impact on the
ecosystem and human health. Although heavy
metals are usually present in ambient air at low
levels, their deposition in soils and water leads to a
buildup in the environment. Due to their properties, heavy metals are very persistent and are not
easily bound or deactivated in the environment.
This, combined with their toxicity, can result in
serious adverse health effect even at low concentration exposures [55]. Many heavy metals are
accumulated in soils and taken up by plants.
Some of them can be transferred from one organism to the other and biomagnified in animals at the
top of the food chain. Oral exposure is the main
route for human exposure to heavy metals. Ingestion of contaminated food and water, in comparison with rather low concentrations of heavy
metals in the ambient air, typically has much
more severe adverse effects. Even small emissions
of heavy metals into atmosphere result in their
deposition into soil. Uptake by plants leads to
contamination of the food chain. Therefore, it is
crucial to control atmospheric emissions in order
to decrease deposition and reduce heavy metal
intake by humans [18]. The assessment of metal
and metalloid compounds in ambient air is complicated due to different properties of existing
species and their reactivity, toxicity, and carcinogenic potential. Hence a good understanding of
different species and their sources is crucial for
proper evaluation of adverse health effects.
The compounds can be characterized using
parameters such as water solubility, particle size
distribution, specific surface area, etc. The parameters will play an important role in their toxicity
and bioavailability [55]. Metal in ambient air is
encountered mainly as a component of particulate
matter. EU air quality standards measure heavy
metals according to their concentration in PM 10 .
However, due to its relatively larger surface area
and its longevity in the atmosphere, fine PM can
have a larger effect on the health impact [56]. Furthermore, fine particles are transported much farther in the atmosphere and affect even the most
remote regions, in contrast to coarse particles
which due to their mass are usually deposited
near the source. The size of a particle will also
determine its deposition in living organisms and
how deeply can they penetrate the respiratory
system and which organs are affected [55].
Industrial Emissions Control Technologies: Introduction
481