can deposit deep in the lungs, introducing foreign
materials into the bloodstream [22]. Coarse particles (diameter > 2.5 mm) are formed predominantly by weathering of Earth’s crust, dust from
industry and roads such as tire wear or dust from
vehicle breaks. Fine particles are mainly the products of combustion and aerosols nucleation. In the
EU, the industrial sector is responsible for 17% of
all emitted PM 2.5 [17]. Industrial processes are the
main source of PM in China followed by stationary combustion involving the power industry,
industry, and residential. The industrial processes
include metallurgical, mineral, and chemical
industries and comprise over half of PM emissions, often due to coal. The production of coal,
coke, sinter, pig iron, steel, cement, brick, lime,
etc. also contribute to PM emissions [21].
Oxidized Compounds
The most relevant oxidized compounds emitted
from industrial processes are carbon dioxide, sulfur dioxide, and nitrogen dioxide.
The CO 2 concentration in the air is 410 ppm
[47]. The atmospheric lifetime of CO 2 is uncertain
due to the complexity of the reservoirs of CO 2 in
the earth system [48]. For example, there are large
fluxes of CO 2 into and out of the ocean with
uptake limited ultimately by mixing of water
into the deep ocean. Similarly, there is an annual
flux of CO 2 into and out of photosynthetic plants
with complicated long-term storage in, e.g., tree
trunks and soil [48]. CO 2 is a greenhouse gas
(GHG), and the contribution of a GHG to GWP
depends on radiative forcing. CO 2 contributes to
global warming with a radiant forcing of 1.67 W/
m
2 [1]. The main source of CO 2 is fossil fuel
combustion including coal, natural gas, and oil;
cement production and land use change are additional factors. The industrial sector includes
manufacturing, construction, mining, agriculture,
etc. Heat from coal burning is needed in industries
such as the cement industry, which uses heat for
cement production. It is also used to produce iron,
steel, chemicals, and petrochemical products. The
natural sinks for CO 2 are photosynthesis and solvation in the ocean, but deforestation, land use,
and increasing urbanization reduce the natural
green areas limiting the natural sinks for CO 2
and thereby increasing the CO 2 concentration in
the atmosphere [49].
NO 2 is a pollutant that is a catalyst for the
formation of photochemical smog and a precursor
of acid rain. Its emission is mostly due to vehicle
exhaust with additional contributions from industrial facilities such as metal refining, food processing, etc.[50]. NO 2 is a toxic component of
urban air.
SO 2 can react with other compounds and form
sulfuric acid and sulfate particles. The source of
the gas is mainly from burning fuel with high
sulfur content (e.g., the shipping industry). Coal
naturally contains sulfur. Burning coal for industrial processes leads to SO x formation, which can
further react with atmospheric water and oxygen
resulting in acid rain [31].
Reduced Compounds
The main reduced compounds are ammonia and
volatile organic compounds (VOC). Methane is
also a VOC, but it is often considered separately
from “non-methane VOC” or NMVOC, because
of its low reactivity and long atmospheric lifetime.
The mean concentration of methane in the atmosphere is 1835 ppb, and the exposure limit is
1000 ppm for 8 hours. Methane is GHG with a
radiative forcing of 0.97 W/m
2 and GWP of 72
over a 20 year time horizon. The main industrial
sources of methane are fossil fuel extraction, agriculture and waste, incomplete biomass burning,
and man-made wetlands [8].
Benzene is one example of a NMVOC. It is a
carcinogen, mainly emitted from burning coal and
oil and from motor vehicle exhaust. The mean
concentration in the EU ranges from 0.5 to
1.3 ppb, but since it’s a toxic substance, there is
no safe level of exposure recommended by the
World Health Organization (WHO) [41, 44].
Another VOC is formaldehyde, which can be
found at highly variable concentrations in the
order of 100 ppb in the atmosphere. A primary
natural source of formaldehyde is biomass burning; a lot of secondary formaldehyde is produced
by the photochemical oxidation of other VOCs in
the atmosphere. Industrial sources of formaldehyde include chemical manufacturing plants,
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Industrial Emissions Control Technologies: Introduction
materials into the bloodstream [22]. Coarse particles (diameter > 2.5 mm) are formed predominantly by weathering of Earth’s crust, dust from
industry and roads such as tire wear or dust from
vehicle breaks. Fine particles are mainly the products of combustion and aerosols nucleation. In the
EU, the industrial sector is responsible for 17% of
all emitted PM 2.5 [17]. Industrial processes are the
main source of PM in China followed by stationary combustion involving the power industry,
industry, and residential. The industrial processes
include metallurgical, mineral, and chemical
industries and comprise over half of PM emissions, often due to coal. The production of coal,
coke, sinter, pig iron, steel, cement, brick, lime,
etc. also contribute to PM emissions [21].
Oxidized Compounds
The most relevant oxidized compounds emitted
from industrial processes are carbon dioxide, sulfur dioxide, and nitrogen dioxide.
The CO 2 concentration in the air is 410 ppm
[47]. The atmospheric lifetime of CO 2 is uncertain
due to the complexity of the reservoirs of CO 2 in
the earth system [48]. For example, there are large
fluxes of CO 2 into and out of the ocean with
uptake limited ultimately by mixing of water
into the deep ocean. Similarly, there is an annual
flux of CO 2 into and out of photosynthetic plants
with complicated long-term storage in, e.g., tree
trunks and soil [48]. CO 2 is a greenhouse gas
(GHG), and the contribution of a GHG to GWP
depends on radiative forcing. CO 2 contributes to
global warming with a radiant forcing of 1.67 W/
m
2 [1]. The main source of CO 2 is fossil fuel
combustion including coal, natural gas, and oil;
cement production and land use change are additional factors. The industrial sector includes
manufacturing, construction, mining, agriculture,
etc. Heat from coal burning is needed in industries
such as the cement industry, which uses heat for
cement production. It is also used to produce iron,
steel, chemicals, and petrochemical products. The
natural sinks for CO 2 are photosynthesis and solvation in the ocean, but deforestation, land use,
and increasing urbanization reduce the natural
green areas limiting the natural sinks for CO 2
and thereby increasing the CO 2 concentration in
the atmosphere [49].
NO 2 is a pollutant that is a catalyst for the
formation of photochemical smog and a precursor
of acid rain. Its emission is mostly due to vehicle
exhaust with additional contributions from industrial facilities such as metal refining, food processing, etc.[50]. NO 2 is a toxic component of
urban air.
SO 2 can react with other compounds and form
sulfuric acid and sulfate particles. The source of
the gas is mainly from burning fuel with high
sulfur content (e.g., the shipping industry). Coal
naturally contains sulfur. Burning coal for industrial processes leads to SO x formation, which can
further react with atmospheric water and oxygen
resulting in acid rain [31].
Reduced Compounds
The main reduced compounds are ammonia and
volatile organic compounds (VOC). Methane is
also a VOC, but it is often considered separately
from “non-methane VOC” or NMVOC, because
of its low reactivity and long atmospheric lifetime.
The mean concentration of methane in the atmosphere is 1835 ppb, and the exposure limit is
1000 ppm for 8 hours. Methane is GHG with a
radiative forcing of 0.97 W/m
2 and GWP of 72
over a 20 year time horizon. The main industrial
sources of methane are fossil fuel extraction, agriculture and waste, incomplete biomass burning,
and man-made wetlands [8].
Benzene is one example of a NMVOC. It is a
carcinogen, mainly emitted from burning coal and
oil and from motor vehicle exhaust. The mean
concentration in the EU ranges from 0.5 to
1.3 ppb, but since it’s a toxic substance, there is
no safe level of exposure recommended by the
World Health Organization (WHO) [41, 44].
Another VOC is formaldehyde, which can be
found at highly variable concentrations in the
order of 100 ppb in the atmosphere. A primary
natural source of formaldehyde is biomass burning; a lot of secondary formaldehyde is produced
by the photochemical oxidation of other VOCs in
the atmosphere. Industrial sources of formaldehyde include chemical manufacturing plants,
480
Industrial Emissions Control Technologies: Introduction