Combustion of fossil fuels,
without using MODERN
air pollution abatement
technology,
releases chemicals
that could be harmful to
humans, other animal life,
and plants.
But when using
modern pollution
controls, emissions
produced from
the use of
fossil fuels
are NOT a threat
to human health.
When burned,
fossil fuels release
carbon dioxide (CO ),
water (H2O),
carbon monoxide (CO),
sulfur dioxide (SO2),
nitrogen oxides (NOx), and
particulate matter (PM).
Carbon dioxide
and water are not
public health concerns.
Carbon monoxide (CO)
is a colorless, odorless gas,
formed when fossil fuels
are not burned completely.
About 80% of human
outdoor CO emissions
in the United States
comes from motor
vehicle exhaust.
The remaining 20%
comes from industrial
processes and residential
wood burning.
( wood stoves, gas stoves,
unvented gas and kerosene
space heaters, and smoking ).
Sulfur dioxide (SO2)
is formed when
fossil fuels containing
sulfur, such as coal and oil,
are burned, when gasoline
is extracted from crude oil,
and when metals are
extracted from ore.
Sulfur dioxide dissolves
in water, creating what
is popularly called
“acid rain.”
Nitrogen oxides (NOx)
A group of gases containing
nitrogen and oxygen, most
of which are colorless and
odorless.
Half of NOx emissions
in the United States come
from motor vehicle exhaust,
and most of the rest from
stationery generators.
Particulate matter (PM)
is a general term used
to describe a mixture
of solid particles and
liquid droplets found
in the air.
PM25 refers to particles
less than or equal to
2.5 μm (micrometer)
in diameter.
“Primary” PM is emitted
directly into the atmosphere,
such as dust from roads
or black carbon (soot)
from burning wood
or fossil fuels.
Fossil fuels create PM
in the form of soot
when the supply
of oxygen
during combustion
is insufficient to
completely convert
carbon to carbon
oxides.
This typically occurs
during the combustion
of coal and oil,
buy not natural gas.
PM also is produced
by farm plowing, planting,
and harvesting, forest fires,
wind erosion, desert dust,
volcanoes, sea salt aerosols,
spores and pollen.
Ozone (O3)
Ozone is created through
photochemical reactions
with the other pollutants.
It's an oxygen molecule
gas not directly emitted
into the atmosphere
when fossil fuels are
combusted.
But ozone precursors
are carbon monoxide,
nitrogen oxides, and
particulate matter.
Trees and other plants
also produce ozone
precursors.
VOCs:
Volatile Organic Compounds
readily evaporate in the air.
Plants produce about ten times
as much VOCs, by weight,
as all human activities.
The combustion of fossil fuels
contributes only a small fraction
of man-made VOCs, with
gasoline fumes as one example.
Lead (Pb)
A lead-containing compound
called tetraethyl lead was once
added to petroleum to improve
engine performance.
It was responsible
for lead emissions
from motor vehicles.
Lead is not found
in appreciable
amounts in coal
or refined oil products.
The main sources
of human lead
emissions today are
waste incinerators
and lead-acid battery
manufacturers.
Mercury emissions from
the combustion of fossil fuels
in the United States are very
small relative to other sources:
Approximately 7 tons annually
(EPA, 2018) versus
5,000 to 8,000 tons
from all sources globally.