Reducing Greenhouse Gas Emissions and Improving Air Quality
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quality. Combustion of coal for industrial production and power generation
contributes to air pollution as well.
The total number of deaths attributed to air pollution is more than 6 million/
year (Baklanov et al., 2016; HEI, 2018). Ambient air pollution contributes to
more than 3 million deaths per year, and household air pollution associated
with combustion for cooking and heating leads to more than 3 million deaths
per year (WHO, 2018). Modern urban cities are home for more than half of
the inhabitants of the world, and megacities with 10 million or more residents
account for about 10% of the global population (Baklanov et al., 2016). The air
quality is poor in many of these large cities.
3.2 Air Pollutants
Air pollution is a general term, and within that broad category there are
several distinctions that can be important. One distinction is the size of the
particles making up the pollution; another distinction is the composition of
the air pollution; yet another is the location of the pollution. Each of these
distinctions carries with it a slightly different set of implications and also
different prescriptions for how to deal with that form of pollution. In terms
of size, particulates in air that are smaller than 2.5 micrometers in equivalent
aerodynamic diameter (PM2.5) are some of the more important air pollutants
because they are strongly associated with health effects. In terms of content,
nitrogen dioxide (NO 2 ), carbon monoxide (CO), and sulfur dioxide (SO 2 )
are present as air pollutants in urban air because of combustion processes.
Other types of pollution, such as smog and ozone (O 3 ) are formed due to
interactions between these harmful substances and other elements in the
air. For example, O 3 is formed in the air through photochemical processes
because of nitrogen oxides and volatile organic compounds (VOCs) that are
present with sunlight in the air. These pollutants are also important to health
and are included in the calculation of the air quality index (AQI) that has
been used to communicate air pollution health risks to the public (Erickson
et al., 2017; USEPA, 2018).
The AQI translates air pollutant concentration data into numbers and
colors that help individuals to know if they need to modify their activities. The AQI has six color- coded categories: Good (green), moderate
(yellow), unhealthy for sensitive groups (orange), unhealthy (red), very
unhealthy (purple), and hazardous (maroon). Since particulate matter,
nitrogen dioxide, and ozone are most important for urban air quality
and health, values for these three pollutants are shown in Tables 3.1 and
3.2. Values for the National Ambient Air Quality Standards (NAAQS) are
shown in Table 3.1, while the range for each AQI category is shown for
each pollutant in Table 3.2. The primary standards in Table 3.1 are meant
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quality. Combustion of coal for industrial production and power generation
contributes to air pollution as well.
The total number of deaths attributed to air pollution is more than 6 million/
year (Baklanov et al., 2016; HEI, 2018). Ambient air pollution contributes to
more than 3 million deaths per year, and household air pollution associated
with combustion for cooking and heating leads to more than 3 million deaths
per year (WHO, 2018). Modern urban cities are home for more than half of
the inhabitants of the world, and megacities with 10 million or more residents
account for about 10% of the global population (Baklanov et al., 2016). The air
quality is poor in many of these large cities.
3.2 Air Pollutants
Air pollution is a general term, and within that broad category there are
several distinctions that can be important. One distinction is the size of the
particles making up the pollution; another distinction is the composition of
the air pollution; yet another is the location of the pollution. Each of these
distinctions carries with it a slightly different set of implications and also
different prescriptions for how to deal with that form of pollution. In terms
of size, particulates in air that are smaller than 2.5 micrometers in equivalent
aerodynamic diameter (PM2.5) are some of the more important air pollutants
because they are strongly associated with health effects. In terms of content,
nitrogen dioxide (NO 2 ), carbon monoxide (CO), and sulfur dioxide (SO 2 )
are present as air pollutants in urban air because of combustion processes.
Other types of pollution, such as smog and ozone (O 3 ) are formed due to
interactions between these harmful substances and other elements in the
air. For example, O 3 is formed in the air through photochemical processes
because of nitrogen oxides and volatile organic compounds (VOCs) that are
present with sunlight in the air. These pollutants are also important to health
and are included in the calculation of the air quality index (AQI) that has
been used to communicate air pollution health risks to the public (Erickson
et al., 2017; USEPA, 2018).
The AQI translates air pollutant concentration data into numbers and
colors that help individuals to know if they need to modify their activities. The AQI has six color- coded categories: Good (green), moderate
(yellow), unhealthy for sensitive groups (orange), unhealthy (red), very
unhealthy (purple), and hazardous (maroon). Since particulate matter,
nitrogen dioxide, and ozone are most important for urban air quality
and health, values for these three pollutants are shown in Tables 3.1 and
3.2. Values for the National Ambient Air Quality Standards (NAAQS) are
shown in Table 3.1, while the range for each AQI category is shown for
each pollutant in Table 3.2. The primary standards in Table 3.1 are meant