The effects of
seasonal
changes on dust
control are
broad and
unique. Natural
phenomena such
as sand and
dust events are
uncertain
occurrences
which differ
from dust
generated from
unlike
anthropogenic
activities. The
sole focus of
the discussion
will bring to
the fore the
importance of
understanding
seasonal
changes of dust
events through
examples from
different parts
of the world.
Firstly, we
will evaluate
dust as a
natural
phenomenon
tracking how it
can spread
across the
world
especially
looking at the
impact on air
quality which
will filter
down to the
particle size
classifications.
Anthropogenic
dust generation
and how
seasonal
changes affects
dust control
will be
analyzed in a
quarry mine
scenario.
Secondly, a
discussion into
the variations
of these
seasonal
changes across
different parts
of the world
seeks to
categorize dust
events based on
location and
prevalence of
them occurring.
Dust control
and its
varieties
related to
natural dust
events are
important to
reduce the
effects of dust
particles to
the humans,
infrastructure
and the
environment.
This will be
analyzed as the
last section of
the article
with intent to
consolidate the
available
methods and how
they might
assist in
reducing the
effect of dust.
Aeolian
soil
transport
Sand-dust
events that
happen due to
changes in the
atmospheric
conditions and
physical
characteristics
of the earth
surface are
often
unfavorable
weather
occurrences,
which are
common in arid
and semi-arid
regions of the
world.
Transportation
of dust
particles by
strong winds
happens at
different
distances which
has been
escalated by
climate change
and
desertification
in recent
times.
Particulate
matter
aerodynamic
diameters are
used to
classify the
dust particles
but most
importantly the
chemical
constituent of
the particles
is key to
revealing the
toxicity and
eventually
understanding
the
pathogenicity
which makes the
control much
more targeted.
The aerosol
nature of dust
and its mineral
form can also
directly change
global
radiation
balance through
reflection,
scattering and
absorbing solar
short-wave
radiation and
ground long
wave radiation.
It can also act
as nuclei for
cloud
condensation,
giant cloud
condensation
and ice owing
to its ability
to change cloud
microphysical
structures and
rainfall
processes. Dust
aerosol affects
atmospheric
chemistry and
the earth’s
biological
cycle, and its
deposition on
oceans can
initiate the
biological pump
effect in
addition to
global climate
change
centering.
Sensitive
receivers
Cities
and towns
within the
vicinity of a
quarry or mine
are most likely
to be
vulnerable to
the effects of
quarry/mining
dust
particulate
matter most
especially
through
transport of
the smallest
particle sizes
that travel the
longest
distance from
their source.
Seasonal
variations in
PM2.5 and
quarry mining
dust source
samples have
been observed
with deductions
showing that
the
concentration
of the former
is highest in
autumn and
lowest in
summer. In the
latter, mass
fractions of
silica and
aluminum did
not show
seasonal
variations
however calcium
showed higher
fractions in
spring and
summer and
lower fractions
in autumn and
winter. PM2.5
is a pollutant
in ambient air
and considered
an important
factor in
regional air
quality,
climate
impacts,
economic
concerns and
human health.
Anthropogenic
dust generated
from quarry
mines on the
other hand is
an important
contributor to
PM2.5 mass
concentration
in urban areas.
Quarry dust is
mainly
generated from
stockpiling,
loading,
transportation
and processing
of mineral
materials in
quarries and
from open air
storage of
mineral
materials.
World over as
the consumption
of minerals
continues to
increase and
the effects of
the quarry mine
dust will even
rise to
alarming levels
hence there
need to be
measures in
place to
protect human
life and the
environment.
From
top to
bottom
We
will start off
in Sweden,
where road dust
load dynamics
and its
influencing
factors was
monitored for
six winter
seasons. The
road dust in
question was
considered to
be originating
from dust that
accumulates on
the road
surface and how
the surface
properties
contributed to
the subsequent
emissions.
Surface
macrotexture
was critical to
analysis of
road dust
accumulation
and its
availability
for suspension
by traffic
evident in
higher dust
loads with
coarser macro
texture. The
study found out
that seasonal
dependency in
road dust loads
depends on the
build-up in
autumn, with
maximum loads
achieved in
mid-winter to
early spring
and low values
in late spring
and autumn. We
move to mid and
low latitudes
of Asia, with
focus on
seasonal and
interannual
variations of
atmospheric
dust aerosols.
The findings
showed that the
maximum dust
aerosols in
spring resulted
from soil
wetness, snow
depth and
vertical wind
shear in the
lower
troposphere.
Moving along,
for the Arabian
Peninsula and
the Middle
East, North
Africa and
Australia dust
transport in
these dust
regions was
found to be
controlled by
mid-latitude
westerlies with
predominant
dust transport
from west to
east. However,
the dust
aerosol in the
atmospheric
boundary layer
shows distinct
regional
characteristics,
with
inter-annual
and seasonal
variation that
are weak and
strong
respectively.
The
role of
vegetation
Enhanced
vegetation
cover protects
the soil
against wind
erosion which
is related to
the ability to
reduce the
effects of
dust. The
seasons and
vegetation
growth play an
important role
in dust
reduction, for
example, the
increase in
spring
vegetation
growth is
directly
related to the
decline in
spring dust
particles.
Improvement in
vegetation
status weakens
wind speed
which in turn
decreases the
likelihood of
dust particle
dislodgement.
Windbreaks can
also be another
measure
implemented to
effectively
reduce wind
erosion in dust
prone sandy
areas. Surface
wind speeds can
decrease soil
moisture and
increase the
likelihood of
wind erosion
events and dust
emission.
Vegetation
phenology can
be used to
depict growth
characteristics
of vegetation,
an integrated
indicator of
climate and
underlying
surface
conditions,
reflect the
impact of
climate change
on the
commonality of
dust storms.
The mineralogy
and surface
characteristics
of quarry mine
dust determine
the dust
control measure
to be
implemented. It
is important to
match the size
of the dust
particles at
the source with
dust control
product to make
the process of
dislodging
buoyant dust
particles more
effectively.
Seasonal
vs
Man-Made
Dust
generation is
very closely
related to
seasonal
changes, which
strongly
depends on the
region of the
dust source and
transport over
time.
Consequently,
when the dust
is a naturally
driven
phenomenon it
travels over
long distances
and along the
way poses
threats to
human life and
the
environment.
Anthropogenic
activities that
generate dust
can include but
are not limited
to quarrying,
mining and road
use.
Agriculture and
farming is also
a large source,
as well as
timber getting.
Understanding
dust and its
origins as a
natural
phenomenon is
very important
and critical to
the
implementation
of different
measures to
ameliorate
dust, which
differs from
one region to
the other. From
region to
region it has
been shown that
seasonal
variations
affect the
generation of
dust from
summer, winter,
autumn and
spring.
Although
seasonal
variations are
important to
the discussion,
it should also
be mentioned
that other
factors
contribute to
the
proliferation
of dust most
importantly the
atmospheric
conditions and
physical
characteristics
of the earth
surface.
Vegetative
cover can play
a huge role in
abatement of
dust on a
larger scale
through slowing
down the
effects of wind
erosion.
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