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Q: Sulphur Dioxide ( Answered 4 out of 5 stars,   2 Comments )
Subject: Sulphur Dioxide
Category: Health > Medicine
Asked by: diltan-ga
List Price: $35.00
Posted: 16 Jan 2003 13:39 PST
Expires: 15 Feb 2003 13:39 PST
Question ID: 144383
What is the short and long term effects of Sulphur Dioxide Fumes on the body.
Subject: Re: Sulphur Dioxide
Answered By: kevinmd-ga on 16 Jan 2003 14:58 PST
Rated:4 out of 5 stars
Thanks for asking your question.  You asked the following:
"What is the short and long term effects of Sulphur Dioxide Fumes on
the body?"

What is sulphur dioxide?
From Aerias:
"Sulfur dioxide (S02) is a colorless gas or liquid with a suffocating
and pungent odor. It is a common combustion pollutant. It is an
important outdoor air pollutant given off by coal burning power
plants. This is because some coal is contaminated with sulfur. When
the coal is burned, the sulfur dioxide is released into the air. If
there is moisture in the air, the sulfur dioxide dissolves into the
moisture creating acid rain (sulfuric acid)."

1) Short term effects

Aerias nicely describes the short term, or acute effects of sulphur
"Acute effects to low levels of sulfur dioxide include irritation of
the eyes, nose, and respiratory tract. Because S02 dissolves easily in
water, even low levels can be very irritating. Repeated exposures may
result in:
Headache, Dizziness, Nausea

Acute effects to high levels can possibly burn the skin and eyes and
may result in permanent eye damage. High levels may also cause
pulmonary edema (when the lungs fill up with fluid). This is a true
medical emergency since oxygen cannot get through the fluid so the
person may die. S02 can also cause the airway passages in the lung to
narrow resulting in wheezing, chest tightness, or breathing problems."

OSH Answers gives some short term effects:
"In severe cases where very high concentrations of SO2 have been
produced in closed spaces, SO2 has caused severe airways obstruction,
hypoxemia (insufficient oxygenation of the blood), pulmonary edema (a
life threatening accumulation of fluid in the lungs), and death in
minutes. The effects of pulmonary edema include coughing and shortness
of breath which can be delayed until hours or days after the exposure.
These symptoms are aggravated by physical exertion. As a result of
severe exposures, permanent lung injury may occur." describes some short term effects of sulfur dioxide:
"Sulfur dioxide fumes are not absorbed into the body and do not
penetrate through the skin. The toxic effects of sulfur dioxide are
derived wholly from its ability to directly irritate the eyes, the
moist mucous membranes of the upper respiratory tract, and the lung.
Acute impairment of lung function associated with toxicologically
significant exposure to sulfur dioxide is obstructive in nature due,
at least in part, to irritant-induced bronchoconstriction.

Controlled studies in humans have documented that acute inhalation of
sulfur dioxide can cause bronchoconstriction, particularly in
asthmatics. As a group, exercising asthmatics are probably the persons
most susceptible to sulfur dioxide inhalation, often responding
adversely to levels of 0.1 ppm. Among healthy volunteers, the
threshold for respiratory function changes is about 1.0 ppm over a
period of several hours. These acute functional changes,
reflex-mediated bronchoconstriction, tend to disappear during exposure
or shortly thereafter. It is not clear whether adaptation to these low
concentrations takes place with repeated exposure, although workers
exposed to sulfur dioxide on a daily basis appear to develop some
tolerance to its irritating effects.

A biphasic response to exposure to very high concentrations of sulfur
dioxide has been described. The first phase consists of immediate
symptoms of eye, nose, and throat irritation with chest tightness and
non-productive cough. The second phase, appearing several weeks later,
is characterized by respiratory failure due to fibrosis of the
terminal bronchioles (bronchiolitis obliterans)."

From ToxFAQs, some words on short term effects:
"Exposure to very high levels of sulfur dioxide can be life
threatening. Exposure to 100 parts of sulfur dioxide per million parts
of air (100 ppm) is considered immediately dangerous to life and
health. Burning of the nose and throat, breathing difficulties, and
severe airway obstructions occurred in miners who breathed sulfur
dioxide released as a result of an explosion in a copper mine."

2) Long term effects

Aerias briefly mentions some long term effects:
"Repeated, long-term exposure to lower levels of sulfur dioxide may: 
Decrease pulmonary function
Cause bronchitis to develop with cough and phlegm production"

From Clean it up or close it
"Sulfur Dioxide: This gas causes permanent pulmonary impairment with
long-term exposure." describes some long term effects, especially in
associated with reactive airways disease (RADS):
"Sulfur dioxide exposure and reactive airway dysfunction syndrome

In 1985, Brooks and his colleagues described an asthma-like illness in
men who had undergone a single inhalation exposure to high levels of
an irritating vapor, fume, or smoke. The investigators termed this
illness "reactive airway dysfunction syndrome (RADS)". None of the
affected individuals had preexisting respiratory disease and,
following exposure, all showed positive methacholine challenge tests.
Brooks and his colleagues established eight clinical criteria for the
diagnosis of RADS: 1. Documented absence of preceding respiratory
complaints; 2. Onset of symptoms after a single, specific exposure; 3.
Exposure was to an irritating gas, smoke, fume or vapor present in
very high concentrations; 4. Onset of symptoms within 24 hours after
exposure and persisting for least three months; 5. Symptoms were
asthmatic in nature; 6. Pulmonary function test may show airflow
obstruction; 7. Methacholine challenge testing was positive in every
case; and 8. Other types of pulmonary diseases were ruled out."

From ToxFAQs, some words on long term effects:
"Long-term exposure to persistent levels of sulfur dioxide can affect
your health. Lung function changes were seen in some workers exposed
to low levels of sulfur dioxide for 20 years or more. However, these
workers were also exposed to other chemicals, so their health effects
may not have been from sulfur dioxide alone. Asthmatics have also been
shown to be sensitive to the respiratory effects of low concentrations
of sulfur dioxide.

Animal studies also show respiratory effects from breathing sulfur
dioxide. Animals exposed to high concentrations of sulfur dioxide
showed decreased respiration, inflammation of the airways, and
destruction of areas of the lung."

OSH Answers answers what the long term effects are in this segment:
"RESPIRATORY EFFECTS: Several human studies have shown that repeated
exposure to low levels of SO2 (below 5 ppm) has caused permanent
pulmonary impairment. This effect is probably due to repeated episodes
of bronchoconstriction. One study has found a decrease in lung
function in smelter workers exposed for over 1 year to 1-2.5 ppm SO2.
No effect was seen in the same study in workers exposed to less than 1
ppm. In another study, a high incidence of respiratory symptoms was
reported in workers exposed to 20-30 ppm for an average of 4 years.
Workers exposed to daily average values of 5 ppm SO2 (with occasional
peaks of 53 ppm) had a much higher incidence of chronic bronchitis
than controls.

There are numerous studies on the potential effects of SO2 as a
component of air pollution. These studies are difficult to interpret
because of confounding factors and uncertainty about exposure

SKIN: There are two case reports of individuals developing skin
eruptions after repeated inhalation of high concentrations. In later
tests, it was found that as little as a 30-minute exposure to 10 ppm
SO2 or a 1-hour exposure to 4 ppm SO2 could produce the skin
eruptions. The eruptions disappeared after removal from exposure.
These particular reactions are probably rare as there are no other
reports of this type of reaction."

Please use any answer clarification before rating this answer. I will
be happy to explain or expand on any issue you may have.  
Kevin, M.D.         
Internet search strategy:    
Using FAST, Google, Inktomi and Teoma via 
sulfur dioxide toxicology
sulfur dioxide short term effects
sulfur dioxide long term effects

Your home: Sulphur dioxide

New Jersey Hazardous Substance Fact Sheet. Sulfur dioxide. Date
accessed October 2000:

ToxFAQs - Sulfur dioxide

ATSDR: Toxicological profile: Sulfur dioxide

OSH Answers - Health Effects of Sulfur Dioxide

Wisconsin Department of Natural Resources

Request for Answer Clarification by diltan-ga on 17 Jan 2003 06:57 PST
What are the long term effects of Sulphur Dioxide Fumes on the body at low ppm.
And is the liver effected over time.

Clarification of Answer by kevinmd-ga on 18 Jan 2003 05:59 PST
Thanks for your clarification request.  You asked the following:
"What are the long term effects of Sulphur Dioxide Fumes on the body
at low ppm. And is the liver effected over time."

1) Long term effects of sulfur dioxide funes at low ppm.

OSH Answers suggests that doses as small as 1-2.5 ppm cuases lung
"Several human studies have shown that repeated exposure to low levels
of SO2 (below 5 ppm) has caused permanent pulmonary impairment. This
effect is probably due to repeated episodes of bronchoconstriction.
One study has found a decrease in lung function in smelter workers
exposed for over 1 year to 1-2.5 ppm SO2."

They also suggest that small doses causes skin eruptions:
"In later tests, it was found that as little as a 30-minute exposure
to 10 ppm
SO2 or a 1-hour exposure to 4 ppm SO2 could produce the skin

2) Is the liver effected over time?

A thorough Medline and Internet search did not yield a definite
connection between liver toxicity and sulfur dioxide exposure.  I
would have to agree with the commenter below - there is no clear
association between sulfur dioxide and the liver.

I did find one study that suggested this.

Pool (1988) studies the exposure of sulfur dioxide on liver cells
(hepatocytes) of rats.  They found that the viability of the
hepatocytes was not affected by the administration of sulfur dioxide
at 50ppm:
“Short term in vivo studies were performed to study biological effects
of the common air pollutants SO2 or NOx and their influence on the
genotoxic activities of nitrosamines. Hepatocytes and lung cells were
isolated from Sprague-Dawley rats which had inhaled 50 p.p.m. of SO2
or NOx for 2 weeks. After incubating the cells for 1 h, genotoxicity
was determined in hepatocytes by measuring DNA single-strand breaks
induced by N-nitroso-acetoxymethylmethylamine, N-nitrosodimethylamine
and N-nitrosomethylbenzylamine. Parameters of toxicity (trypan blue
exclusion and leakage of serum enzymes) were determined in both liver
and lung cells also following 1 h incubation. The activities of aryl
hydrocarbon hydroxylase (AHH), nitrosodimethylamine demethylase
(NDMA-D) and glutathione-S-transferase (GST) were determined in
subcellular microsomal fractions isolated from lung and liver tissues.
Finally, as a measure of overall toxicity, the activities of various
serum enzymes were determined in the blood serum of the rats. It was
found that the induction of DNA single-strand breaks by three
nitrosamines was decreased in hepatocytes from SO2-treated animals.
The viability of rat hepatocytes and of rat lung cells, as determined
by trypan blue exclusion, was similar in all three treatment groups
immediately after isolation.”

Pool BL. Brendler S. Klein RG. Monarca S. Pasquini R. Schmezer P.
Zeller WJ. Effects of SO2 or NOx on toxic and genotoxic properties of
chemical carcinogens. II. Short term in vivo studies. Carcinogenesis.
9(7):1247-52, 1988 Jul.

Kevin, M.D.

Internet search using
Sulfur dioxide and liver
Sulfur dioxide and liver toxicity
Sulfur dioxide toxicology and liver

Medline search:
Sulfur dioxide and liver
diltan-ga rated this answer:4 out of 5 stars and gave an additional tip of: $10.00
Very good thank you

Subject: Re: Sulphur Dioxide
From: neilzero-ga on 18 Jan 2003 05:24 PST
One of the source in the the answer by Kevin said that sulfer dioxide
does not penetrate the body, even in the lungs. If so, no DIRECT harm
can occur to the liver. The bodies immune system is kept busy
repairing damage to lung tissue and other mucus membrains, so the
activity of the imune system will put extra strain on the liver.
 Sulfer dioxide dissolves in water to form a weak acid = supherous
acid = H2SO3. Exposed to air and sun light, tiny drops of sulperous
acid become sulpheric acid = H2SO4 which is a strong acid which may
have mechanisms whereby it can penetrate the human body and cause harm
to the liver by means other than waste products produced by the immune
system. So you may want to pursue Sulpher Trioxide = SO3, and droplets
of sulpheric acid, if you think the sulfer dioxide is exposed to
sunlight for hours or days, before it is inhailed. Sulfer trioxide and
sulpheric acid are more harmful to lung tissue and mucus membrains
than sulper dioxide and sulpherous acid.   Neil
Subject: Re: Sulphur Dioxide
From: kevinmd-ga on 20 Jan 2003 05:54 PST
Thank you for the tip!

Kevin, M.D.

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