more concentrated sources, and the ability for the
pollutants in the air to be dispersed is limited by
the physical constraints of the urban environment.
Urban air quality varies significantly in between
urban cities around the world generally because of
the differences in control on pollution sources but
also due to differences in meteorology and, e.g.,
the domestic use of open fires and wood stoves in
the urban areas. Nevertheless, across the world,
illness, deaths, and damage to the environment are
still attributed to air pollution.
Worldwide, the United Nations Environment
Programme (UNEP) (http://www.unep.org/urban_
environment/issues/urban_air.asp, accessed February
13, 2010) reported in 2010 that an estimated more
than 1 billion people annually are exposed to ou
tdoor air pollution as seen further below; the nu
mbers in the Asian and Pacific Region have
more than doubled to the present time. There
fore since 2010, it can be expected that over one
million premature deaths each year are linked to
urban air pollution in the ambient environment.
Given primarily these deaths and other health
costs and loss of productivity, urban air pollu
tion is estimated to cost approximately 2% of
GDP in developed countries and 5% in deve
loping countries.
UNEP further reported that rapid urbanization
has resulted in increasing urban air pollution in
major cities, especially in developing countries
with over 90% of air pollution in major cities in
developing countries attributed to vehicle emissions brought about by high numbers of older
vehicles coupled with poor vehicle maintenance,
inadequate infrastructure, and poor fuel quality
with high amounts of sulfur in the fuel.
Most developed countries have put in measures
to reduce vehicle emissions, in terms of fuel quality, by, for example, regulating the amount of sulfur, benzene, and additives like lead in vehicle fuel
and vehicle emission reduction technologies such
as catalytic converters; these measures are yet to be
adopted in most cities in developing countries, and
there are recent cases where vehicle manufactures
save costs by not utilizing such technologies while,
at the same time, lowering overall vehicle prices,
thus enhancing the number of vehicles on the road
with all of the subsequent effects on air quality.
UNEP in a 2019 report, “Air pollution measures
for Asia and the Pacific 25 science-based solutions
to bring clean, safe air to 1 billion people” (http://
www.ccacoalition.org/en/content/air-pollution-mea
sures-asia-and-pacific, accessed May 1, 2019, or
the report itself http://www.ccacoalition.org/en/
file/5802/download?token=dBM5KOkC accessed
May 1, 2019), states that “2.3 billion people in the
region are exposed to levels of air pollution several
times the WHO guideline for safe air” and that
“some of the highest recorded levels of air pollution
are in Asia Pacific countries” with “92% of the Asia
and the Pacific’s population, about 4 billion people,
exposed to levels of air pollution that pose a significant risk to their health” – many of these are in
urban areas that will likely continue to grow and,
unless the 25 recommended solutions from the
report followed, continue to pose a health risk to
the people as well as miss an opportunity to significantly benefit other UN sustainable development
goals, climate, food, and water security of the
regions.
Air quality as a term is subjectively defined
generally through laws regulating the maximum
concentrations of pollutants in the atmosphere via
the maximum allowable emissions from sources.
The quality of the ambient (outside) air is monitored, in some urban environments, continuously
with advanced equipment and generally reported
in some type of index by local or national authorities, a so-called air quality index.
Despite relatively unchanged levels of pollutants, the air quality can be improved or degraded
based on the weather and topography of the urban
environment. It is therefore a very complicated
issue to manage and predict. Many municipalities
therefore have air quality management (AQM)
offices and/or plans.
There are specific mathematical models developed to predict air quality and support the air
quality policies that naturally must be aligned
with policies affecting the other environmental
compartments.
In cities in the industrialized world, air quality
has generally improved after controls and policies
on pollution and emittants were emplaced during
the past decades. The policies have been the result
of international treaties, as well as national and
Urban Air Quality: Sources and Concentrations
195
pollutants in the air to be dispersed is limited by
the physical constraints of the urban environment.
Urban air quality varies significantly in between
urban cities around the world generally because of
the differences in control on pollution sources but
also due to differences in meteorology and, e.g.,
the domestic use of open fires and wood stoves in
the urban areas. Nevertheless, across the world,
illness, deaths, and damage to the environment are
still attributed to air pollution.
Worldwide, the United Nations Environment
Programme (UNEP) (http://www.unep.org/urban_
environment/issues/urban_air.asp, accessed February
13, 2010) reported in 2010 that an estimated more
than 1 billion people annually are exposed to ou
tdoor air pollution as seen further below; the nu
mbers in the Asian and Pacific Region have
more than doubled to the present time. There
fore since 2010, it can be expected that over one
million premature deaths each year are linked to
urban air pollution in the ambient environment.
Given primarily these deaths and other health
costs and loss of productivity, urban air pollu
tion is estimated to cost approximately 2% of
GDP in developed countries and 5% in deve
loping countries.
UNEP further reported that rapid urbanization
has resulted in increasing urban air pollution in
major cities, especially in developing countries
with over 90% of air pollution in major cities in
developing countries attributed to vehicle emissions brought about by high numbers of older
vehicles coupled with poor vehicle maintenance,
inadequate infrastructure, and poor fuel quality
with high amounts of sulfur in the fuel.
Most developed countries have put in measures
to reduce vehicle emissions, in terms of fuel quality, by, for example, regulating the amount of sulfur, benzene, and additives like lead in vehicle fuel
and vehicle emission reduction technologies such
as catalytic converters; these measures are yet to be
adopted in most cities in developing countries, and
there are recent cases where vehicle manufactures
save costs by not utilizing such technologies while,
at the same time, lowering overall vehicle prices,
thus enhancing the number of vehicles on the road
with all of the subsequent effects on air quality.
UNEP in a 2019 report, “Air pollution measures
for Asia and the Pacific 25 science-based solutions
to bring clean, safe air to 1 billion people” (http://
www.ccacoalition.org/en/content/air-pollution-mea
sures-asia-and-pacific, accessed May 1, 2019, or
the report itself http://www.ccacoalition.org/en/
file/5802/download?token=dBM5KOkC accessed
May 1, 2019), states that “2.3 billion people in the
region are exposed to levels of air pollution several
times the WHO guideline for safe air” and that
“some of the highest recorded levels of air pollution
are in Asia Pacific countries” with “92% of the Asia
and the Pacific’s population, about 4 billion people,
exposed to levels of air pollution that pose a significant risk to their health” – many of these are in
urban areas that will likely continue to grow and,
unless the 25 recommended solutions from the
report followed, continue to pose a health risk to
the people as well as miss an opportunity to significantly benefit other UN sustainable development
goals, climate, food, and water security of the
regions.
Air quality as a term is subjectively defined
generally through laws regulating the maximum
concentrations of pollutants in the atmosphere via
the maximum allowable emissions from sources.
The quality of the ambient (outside) air is monitored, in some urban environments, continuously
with advanced equipment and generally reported
in some type of index by local or national authorities, a so-called air quality index.
Despite relatively unchanged levels of pollutants, the air quality can be improved or degraded
based on the weather and topography of the urban
environment. It is therefore a very complicated
issue to manage and predict. Many municipalities
therefore have air quality management (AQM)
offices and/or plans.
There are specific mathematical models developed to predict air quality and support the air
quality policies that naturally must be aligned
with policies affecting the other environmental
compartments.
In cities in the industrialized world, air quality
has generally improved after controls and policies
on pollution and emittants were emplaced during
the past decades. The policies have been the result
of international treaties, as well as national and
Urban Air Quality: Sources and Concentrations
195