http://vulcan.wr.usgs.gov/Glossary/Emissions/Publications/OFR95-85/OFR95-85.html
“One of the most serious hazards occurs when volcanoes
emit large quantities of carbon dioxide. Carbon dioxide is heavier than air and
collects in low spots, displacing air in these locations. Hundreds of
people have died of carbon dioxide asphyxiation near volcanoes in the past two
decades, most of them in Cameroon, Africa, and in Indonesia.”
http://www.boc-gases.com/products_and_services/by_product/carbon_dioxide
“Carbon dioxide is an inert gas that can cause oxygen
depletion inducing asphyxiation and death. The risk of asphyxiation is
exacerbated by the fact that carbon dioxide is heavier than air which allows it
to flow downwards and collect in low lying areas far from its origin.”
http://www.madehow.com/Volume-1/Baking-Soda.html
“In addition to its many home uses, baking soda also
has many industrial applications. For instance, baking soda releases carbon
dioxide when heated. Since carbon dioxide is heavier than air, it can
smother flames by keeping oxygen out, making sodium bicarbonate a useful
agent in fire extinguishers.”
http://hvo.wr.usgs.gov/volcanowatch/2005/05_06_02.html
“Because CO2 is heavier than air, it doesn't readily
rise into the atmosphere and, instead, tends to pool in low areas.”
http://volcano.oregonstate.edu/vwdocs/frequent_questions/grp7/africa/question627.html
“Carbon dioxide is denser than air, so it hugged the
ground and flowed down the stream valley that leads away from the lake.
Unfortunately many homes and at least one town are also along this valley and
the inhabitants were caught by this cloud of ground-hugging gas.”
http://www.ens-newswire.com/ens/nov2005/2005-11-04-09.asp
“Zhang said, ‘Carbon dioxide is denser than air, so it settled
down and flowed along the river valley, choking people and animals to
death.’”
http://www.freepatentsonline.com/5394643.html
“The carbon dioxide settles as a layer at the
floor of the space.”
http://www.exo.net/~pauld/lectures/italy/marslectureshort.htm
“Carbon dioxide is heavier than air and so it sinks
into the tank and stays there.”
http://www.ibiblio.org/pub/academic/agriculture/entomology/beekeeping/bee-l/log9911a.txt
“In a place with no air movement like the bottom of a
dry well, if you put a lot of organic materials there to rot, Carbon Dioxide
will accumulate at the bottom and it will displace the air.”
http://www.gi.alaska.edu/ScienceForum/ASF7/785.html
“It was May, 1947, near Hekla Crater in southwest
Iceland, an onlooker would have observed a curious scene. Workers were digging
seemingly aimless ditches across the landscape, as if trying to drain invisible
ponds. In fact, that is exactly what they were doing.
During the Hekla eruption of
1947-48, streams issuing from beneath the new lava flows began to precipitate
lime. At the same time, bird and animal carcasses began turning up in low areas
of the topography around the crater. The implications were clear: the volcano
was exhaling carbon dioxide. In the water, the carbon dioxide was combining
with calcium to produce calcium carbonate, or lime, and there were areas on the
ground where the gas collected in concentrations strong enough to suffocate the
animals. Being heavier than air, carbon dioxide will flow like water across
the terrain and collect in low spots, forming ‘ponds’ that are invisible and
odorless, but lethal. (The largest pond associated with the Hekla event covered
an area of about two acres.)
Carbon dioxide in small
amounts is nontoxic, but concentrations of eight percent will make people feel
dizzy, vomit, and faint; higher concentrations quickly induce heart failure and
death. Evidently, the Hekla ponds formed in completely calm weather, and
usually at night. Animals that happened to be in low areas when the carbon
dioxide accumulated didn't stand much of a chance. It was found that mice
placed into a pond would suffocate in less than a minute.”
http://pubs.usgs.gov/dds/dds-81/Intro/MonitoringData/CO2/CO2.html
“The CO2 is released as a cool, diffuse gas from broad
areas of soil. Although it quickly dissipates when it leaves the ground, CO2
is heavier than air and can collect in depressions in the land surface, in
unvented buildings, and in other confined spaces. Carbon dioxide displaces
oxygen and can cause unconsciousness or asphyxiation very quickly at concentrations
above 30 percent. The National Institute for Occupational Safety and Health
recommends a ceiling limit of 3 percent CO2 for up to 10 minutes for
occupational exposure. Summer-time exposure to high levels of CO2 in the
Horseshoe Lake area may result from lying directly on the ground or digging
pits in the ground. Walking through the area in the summertime is safe for
children and dogs, as long as their heads stay above ground level. During the
winter, CO2 levels can build up beneath the snowpack and the CO2 gas will
preferentially escape around buildings, through tree wells, and through
depressions around large rocks. Such areas should obviously be avoided, as
should snow camping within tree-kill areas.”
http://quake.usgs.gov/prepare/factsheets/CO2/index.html
“CO2 gas is heavier than air, and when it leaks from
the soil it can collect in snowbanks, depressions, and poorly ventilated enclosures,
such as cabins and tents, posing a potential danger to people.”
http://www.ess.washington.edu/SEIS/PNSN/HELENS/info.980701.html
“But because it is heavier than air, carbon dioxide
can concentrate in surface depressions in the dome or crater floor,
especially under calm conditions, and pose an asphyxiation hazard.”
“Gases which are heavier than air such as carbon
dioxide and propane, may lie in a tank or vault for hours or even days after the
containers have been opened.”
http://volcanoes.usgs.gov/Hazards/What/VolGas/volgas.html
“Because carbon dioxide gas is heavier than air, the
gas may flow into in low-lying areas and collect in the soil. The
concentration of carbon dioxide gas in these areas can be lethal to people,
animals, and vegetation.”
“Carbon dioxide dissolves in
soil water and
helps to dissolve plant nutrients for the roots to absorb.”
Email concerning this web page may be sent to David Wozney at dpwozney@ocii.com.