The cloud condensation nuclei counter measures the concentration
of aerosol particles by drawing an air sample through a column with thermodynamically unstable supersaturated water vapor that can condense onto aerosol particles.
Not exact matches
This year, Summit's list
of long - term visitors includes Brandon Strellis, an environmental engineering graduate student from the Georgia Institute
of Technology studying how
aerosols influence how much energy is reflected and absorbed
by Greenland's ice — and where those
particles are coming from.
After allowing for humidity and rainfall, they found that «
aerosol optical thickness» — a measure
of the concentration
of atmospheric
particles — decreased
by only 10 to 15 per cent compared with the same periods in 2002 to 2007 (Geophysical Research Letters, in press).
The team started
by looking at the formation
of the very small
particles — a process called
aerosol nucleation —
by mimicking atmospheric conditions inside an ultraclean steel «cloud chamber», which Kirkby says is the cleanest ever created.
And
by carefully measuring and modeling the resulting changes in atmospheric composition, scientists could improve their estimate
of how sensitive Earth's climate is to CO2, said lead author Joyce Penner, a professor
of atmospheric science at the University
of Michigan whose work focuses on improving global climate models and their ability to model the interplay between clouds and
aerosol particles.
On their own,
aerosol particles are tiny; when a cloud droplet becomes a rain droplet, it grows
by a factor
of a million as droplets crash and coalesce together.
Indeed, the reduction in the emission
of precursors to polluting
particles (sulphur dioxide) would diminish the concealing effects
of Chinese
aerosols, and would speed up warming, unless this effect were to be compensated elsewhere, for instance
by significantly reducing long - life greenhouse gas emissions and «black carbon.»
«When biogenic VOCs are oxidized, they give rise to
aerosol particles that cool the climate
by reflecting part
of the Sun's radiation back into space,» Artaxo said.
Soot
particles, also known as black carbon
aerosols, affect climate
by absorbing sunlight, which warms the surrounding air and limits the amount
of solar radiation that reaches the ground.
These
particles pose health risks to populations, especially to the medically vulnerable,
By infusing CATS data directly into
aerosol models, data from CATS can make a difference in tracking and responding to impacts
of similar events in the future.
Ginot and his team
of researchers can also track
aerosols — small
particles in the atmosphere that fall with snow and get trapped and stored in the ice, layer
by layer, as the years pass.
Like the
particles emitted during volcanic eruptions, sulfate
aerosols cool the Earth
by blocking a portion
of the sun's rays.
That's the conclusion
of a team
of scientists using a new approach to study tiny atmospheric
particles called
aerosols that can influence climate
by absorbing or reflecting sunlight and seeding clouds.
By engineering breaking waves
of natural ocean water under purified air in the lab, they were able to isolate and analyze
aerosols from the spray and determine how life within the water altered the chemistry
of the
particles.
Now an international team
of researchers led
by the lung researcher Marianne Geiser from the Institute
of Anatomy at the University
of Bern and the
aerosol researcher Josef Dommen from the Paul Scherrer Institute PSI has shown that secondary
particles from gasoline combustion in Euro 5 engines directly damage lung tissue as well as weaken its defense functions.
Small
particles called
aerosols that are released into the air
by smoke may also reduce the likelihood
of rainfall.
Therefore, considering the large contribution
of these
particles to the
aerosol mass concentration in the atmosphere and the importance
of the INPs, we study the ability
of these
particles as INPs
by immersion freezing mode.
A team
of scientists led
by Pacific Northwest National Laboratory atmospheric researcher Dr. Susannah Burrows and collaborator Daniel McCoy, who studies clouds and climate at the University
of Washington, reveal how tiny natural
particles given off
by marine organisms — airborne droplets and solid
particles called
aerosols — nearly double cloud droplet numbers in the summer, which boosts the amount
of sunlight reflected back to space.
Why It Matters:
Aerosols, tiny airborne
particles of dust and pollution suspended in the atmosphere, affect the atmosphere and the surface
of Earth
by scattering and absorbing light.
Because much
of Earth's land mass is covered
by plants, there is a large source
of these biogenic
aerosol particles that need to be accounted for in climate change prediction.
A large portion
of secondary organic
aerosols - tiny
particles in the air we breathe that contribute to cloud formation and precipitation - arise from a combination
of man - made pollution and molecules given off
by plant matter.
CLOUD shows that organic vapours emitted
by trees produce abundant
aerosol particles in the atmosphere in the absence
of sulphuric acid.
It is caused
by aerosol particles, but scientists don't know all the details
of the complex chemistry involved.
Secondary organic
aerosols, or SOAs, are created when hydrocarbon gases, given off
by everything from pine trees to snow blowers, undergo a series
of chemical reactions in the atmosphere to produce
particles.
The potential risks around sulfate
aerosol solar geoengineering include alteration
of regional precipitation patterns, its effects on human health, and the potential damage to Earth's ozone layer
by increased stratospheric sulfate
particles.
The planet's albedo, around 30 percent, is governed
by cloud cover and the quantity
of atmospheric
particles called
aerosols.
In this case, large amounts
of sulphate
aerosols (small
particles) are injected into the stratosphere
by large explosive eruptions (the most recent one being Mt. Pinatubo in 1991).
According to «Atmospheric
particles and nuclei»
by Götz et al. (1991), Junge (1963) proposed on the basis
of aerosol measurements that «large» and «giant»
particles (radius greater than 0.1 micro-meter) constitute the majority
of CCN, independently
of their chemical composition.
«A rapid cutback in greenhouse gas emissions could speed up global warming... because current global warming is offset
by global dimming — the 2 - 3ºC
of cooling cause
by industrial pollution, known to scientists as
aerosol particles, in the atmosphere.»
My question is: does the retroreflectivity
of the larger droplets, i.e. back towards the light source, play into the sulfur
aerosol issue or is it simply averaged out
by the bulk effect
of all the
aerosol particles present in the apparently white haze?
The composition
of sea spray
aerosol particles are influenced
by both chlorophyll - a concentrations and microbial degradation.
The spotlight is on the effect
of aerosol -
particles released
by industrial activity - on the Earth's climate.
The Single
Particle Soot Photometer (SP2) measures the soot (black carbon) mass
of individual
aerosol particles by laser - induced incandescence down to concentrations as low as ng / m ^ 3.
Michaels arrives at this incorrect result
by completely ignoring the cooling effects
of sulfate
aerosol particles.»
I write it off as a very real effect that is not well characterized
by the models, probably because these models don't model with enough accuracy the effect
of the additional
aerosol particles on cloud production to properly account for it's full effect on temperature.
These were intriguing, as well as highly speculative: first the possibility
of deliberately using additional targeted
aerosol injection to stimulate coagulation
of the
particles in the volcanic
aerosol; mitigating its effects
by causing the
particles to drop out
of the atmosphere more swiftly.
Hansen's group estimates that
aerosols probably counteract about half
of the warming produced
by man - made greenhouse gases, but he cautions that better measurements
of these elusive
particles are needed.
In response, the IPCC added a cooling factor to its models
of the atmosphere, consisting
of tiny
aerosol particles produced
by the emission
of sulfur dioxide from electric power plants.
Like other tiny atmospheric
particles called
aerosols, black carbon (BC) has a short lifetime in the atmosphere
of about a week because it is removed
by rain or snow.
«The results also show that ionisation
of the atmosphere
by cosmic rays accounts for nearly one - third
of all
particles formed, although small changes in cosmic rays over the solar cycle do not affect
aerosols enough to influence today's polluted climate significantly.»
If the maximum cooling ability
of aerosols is only 1.0 Wm2, as Stevens suggests, the
particles would offset only a third
of warming caused
by greenhouse gases.
Later, the enhancement
of atmospheric
aerosol particle formation
by ions generated from cosmic rays was proposed as a physical mechanism explaining this correlation.
Over the last century, tiny airborne
particles called
aerosols, which cool the climate
by absorbing and reflecting sunlight, have largely cancelled out the effects
of GHG emissions on tropical storm intensity, according to a new scientific review paper published in Science journal.
Now, a group
of scientists at the German Aerospace Center (DLR) supported
by the
Aerosol and
Particle Technology Laboratory
of CPERI / CERTH Greece have built and tested a new solar reactor design that includes storage so it can provide round - the - clock heat like the current fossil - fired method, but without the emissions.
This is an old story: Rasool and (Steve) Schneider published a paper in Science on that day noting that if human - made
aerosols (small
particles in the air) increased
by a factor
of four, other things being equal, they could cause massive global cooling.
The quality
of air is determined to a considerable extent
by aerosol particles.
However, there have been proposals to mitigate climate change not
by decreasing greenhouse gas emissions, but
by increasing the reflection
of incoming solar radiation with mirrors,
aerosols (small
particles), or other means.
Gagné and colleagues showed that sulfate
aerosol particles, which are released
by the burning
of fossil fuels, may have disguised the impact
of greenhouse gases on Arctic sea ice.
Their freezing can either be triggered
by aerosol particles acting as a so - called ice nuclei (IN), or occur homogeneously (without IN) at about − 38 ◦ C The goal
of many laboratory studies was and is to assess the ice nucleation ability
of selected
aerosol particles of a... http://search.proquest.com/openview/421dd0783b387a8e030902328dcc6f23/1.pdf?pq-origsite=gscholar&cbl=105744
Recently it was suggested that the formation
of new atmospheric
aerosol particles is connected with the existence
of thermodynamically stable 1 - to 2 - nm clusters, formed in the atmosphere
by some nucleation mechanism.