Sulfur dioxide fact sheet

Health=20 effects=20
Environmental=20 effects=20
Common=20 uses=20
Sources=20 of emissions=20
Comparison=20 to other substances=20
Physical=20 and chemical properties=20
Sources=20 of information used in preparing this fact sheet

The National Pollutant Inventory (NPI) provides = information on the=20 types and amounts of pollutants being emitted in the Australian = community.

This page provides facts about sulfur dioxide. It describes how you = might be=20 exposed to this substance, how exposure might effect you and the = environment,=20 common uses, comparative data about sulfur dioxide and its physical and = chemical=20 properties.

For more information about some of the terms used in this page, see = the NPI = glossary.

The National Pollutant Inventory (NPI) holds data for all = sources=20 of sulfur dioxide emissions in Australia.

Australia's=20 sulfur dioxide emission report

Health effects

What=20 effect might sulfur dioxide have on my health?=20
How=20 might sulfur dioxide enter my body?=20
How=20 might I be exposed to sulfur dioxide?=20
What=20 are the sulfur dioxide health guidelines?

What effect might = sulfur=20 dioxide have on my health?

Exposure to concentrations of 10 to 50 parts per million for 5 to 15 = minutes=20 causes irritation of the eyes, nose and throat, choking and = coughing.

Exposure of the eyes to liquid sulfur dioxide, (from, for example an=20 industrial accident) can cause severe burns, resulting in the loss of = vision. On=20 the skin it produces burns. Other health effects include headache, = general=20 discomfort and anxiety. Those with impaired heart or lung function and=20 asthmatics are at increased risk. Repeated or prolonged exposure to = moderate=20 concentrations may cause inflammation of the respiratory tract, wheezing = and=20 lung damage. It has also proved to be harmful to the reproductive = systems of=20 experimental animals and caused developmental changes in their = newborn.

How might sulfur = dioxide enter my=20 body?

Sulfur dioxide will enter the body if we breathe in contaminated air. = Upon=20 entry, nose, throat and lungs may be affected. Sulfur dioxide can also = enter our=20 bodies when we eat or drink food or beverages (wine) which contain = sulfur=20 dioxide as a preservative. Sulfur dioxide can enter the body through = skin=20 contact.

How might I be = exposed to=20 sulfur dioxide?

Sulfur dioxide is a common pollutant to which we are exposed at very = low=20 levels every day by breathing air in cities and some industrial = environments.=20 Higher exposure levels are more likely to be found in the workplace = where it is=20 produced as a by-product, such as in smelting and the combustion of coal = or oil.=20 Exposure can also happen from the manufacture of fumigants, food = preservatives,=20 bleaches and wine making. It can be ingested by eating preserved foods = and=20 breathed in causing a risk to asthmatics and other individuals sensitive = to its=20 effects.

See Sources=20 for more information.

What are the sulfur dioxide = health=20 guidelines?

National Ambient Air Quality Standards and Goals:
Averaging period = 1 hour,=20 Maximum 0.2 parts per million, maximum allowable exceedences: 1 day a = year.

Averaging period 1 day, Maximum 0.08 parts per million, maximum = allowable=20 exceedences: 1 day a year.

Averaging period 1 year, Maximum 0.02 parts per million, maximum = allowable=20 exceedences: none.

Addit= ional=20 information on current health and environmental guidelines =

Environmental=20 effects

What=20 effect might sulfur dioxide have on the environment?=20
How=20 might sulfur dioxide enter the environment?=20
Where=20 in the environment do sulfur dioxide end up?=20
What=20 are the sulfur dioxide environmental guidelines?

What effect might = sulfur dioxide=20 have on the environment?

Even low concentrations of sulfur dioxide can harm plants and trees = and=20 reduce crop productivity. Higher levels, and especially the acidic = deposits from=20 acid rain, will adversely affect both land and water ecosystems.

How might sulfur dioxide = enter the=20 environment?

Industrial emissions of sulfur dioxide can produce elevated, but = still low=20 level concentrations in the atmosphere around the source. Volcanic = eruptions,=20 while sporadic, are significant contributors to sulfur dioxide in their = local=20 area, and contribute to global background levels of sulfur dioxide.

Where in the environment does = sulfur=20 dioxide end up?

Sulfur dioxide in the atmosphere is absorbed by soils and plants. It = is also=20 captured within and below clouds and in certain circumstances may raise = the=20 acidity of the resultant rain. This is known as acid rain, which occurs = in=20 Europe and North America, but acid rain, from sulfur dioxide, has not = been=20 documented in Australia.

What are the sulfur dioxide = environmental=20 guidelines?

Note that the emissions data in the NPI database is not = directly=20 comparable with these guidelines.

Addit= ional=20 information on current health and environmental guidelines =

Common uses

As a fruit preserving agent and as a food preservative or = additive.
In the=20 fermentation stage of wine making.
For bleaching textile = fibres.
In the=20 manufacture of paper.
As a disinfectant in breweries and food=20 factories.
As a fumigant for grains, grapes and citrus fruits.

Sources of emissions

Industry=20 sources=20
Diffuse=20 sources, and industry sources included in diffuse emissions data=20
Natural=20 sources=20
Transport=20 sources=20
Consumer=20 products that may contain sulfur dioxide

Industry = sources

Fossil fuel combustion sites particularly coal burning power plants;=20 industrial processes such as wood pulping, paper manufacture, petroleum = and=20 metal refining and metal smelting, particularly from sulfide containing = ores,=20 e.g. lead, silver and zinc ores all emit sulfur dioxide to air.

Diffuse sources, and = industry=20 sources included in diffuse emissions data

Small textile bleaching and food preserving facilities and wineries,=20 fumigation activities all emit sulfur dioxide to air.

Natural = sources

Geothermal activity, including hot springs and volcanic activity; = sulfur=20 dioxide is produced from the natural decay of vegetation on land, in = wetlands=20 and in oceans all emit sulfur dioxide to air.

Transport = sources

Vehicle exhaust.

Consumer products that may contain = sulfur=20 dioxide

Some solvents, dechlorination agents, bleaches and fumigation = products.

Comparison to other = substances

NPI = rank

NPI rank

Approximately 400 substances were considered for inclusion on the = NPI reporting = list. A=20 ranking and total hazard score was given based on health and = environmental=20 hazards and human and environmental exposure to the substance.

Sulfur dioxide was ranked as 4 out of 400. The total hazard score = taking into=20 account both human health and environmental criteria is 2.8.

On a health hazard rating of 0 - 3 sulfur dioxide registers 1.5. A = score of 3=20 represents a very high hazard to health, 2 represents a medium hazard = and 1 is=20 harmful to health.

On an environmental rating of 0 - 3 sulfur dioxide registers 1.3. A = score of=20 3 represents a very high hazard to the environment and 0 a negligible=20 hazard.

Factors taken into account to obtain this ranking and these scores = include=20 the extent of the material's toxic or poisonous nature and/or its lack = of=20 toxicity, and the measure of its ability to remain active in the = environment and=20 whether it accumulates in living organisms. It does not take into = account=20 exposure to the substance. Environmental exposure is reflected in the = NPI rank for = this=20 substance (see comparative data below). A substance that scores highly = as an=20 environmental hazard is oxides of nitrogen at 3.0 and one of the lower = scores is=20 carbon monoxide at 0.8. A substance that scores highly as a health = hazard is=20 arsenic at 2.3 and one of the lowest scores is ammonia at 1.0.

More = information about ranking NPI=20 substances

Physical and chemical = properties

Substance name	Sulfur dioxide
CASR number	7446-09-5
Molecular formula	SO₂
Synonyms	sulfurous oxide, sulfur oxide, sulfurous anhydride, sulphur=20 dioxide
*Physical = properties:* Colourless=20 gas. Strong, suffocating odour. Melting Point (=B0C):=20 -75.51 Boiling Point (=B0C): -10.06 Specific Gravity:=20 0.00293 Vapour Density: 2.26
*Chemical=20 properties:* Non-flammable gas. Sulfur dioxide = may=20 oxidise to sulfur trioxide which then dissolves in water to = produce=20 sulfuric acid.

Sources of information used in = preparing this=20 fact sheet

Australian and New Zealand Environment and Conservation Council = (ANZECC) (1992), Australian Water Quality = Guidelines=20 for Fresh and Marine Waters.=20
ChemFinder WebServer Project (1995) (accessed, December, 1998)=20
Meagher, D (1991), The Macmillan Dictionary of The Australian = Environment,=20 Macmillan Education Australia Pty Ltd.=20
Messer MG Industries (1997), Material Safety Data Sheets (MSDS) = (accessed,=20 December, 1998)=20
Micromedex (1995), Knowledge Bases for Healthcare, Safety and the=20 Environment (accessed, December, 1998)=20
National Academy of Sciences (1995), Laboratory Safety: Sulfur = Dioxide=20 (accessed, December, 1998)=20
National Environment Protection Council (1998), National = Environment=20 Protection Measure for the National Pollutant Inventory. (accessed, = December,=20 1998)=20
National Environment Protection Council (1998b), National = Environment=20 Protection Measure for Ambient Air Quality.=20
National Health and Medical Research Council (NHMRC) and Agriculture and Resource = Management Council=20 of Australia and New Zealand (ARMCANZ ) (1996), Australian Drinking Water=20 Guidelines.=20
National Library of Medicine (1997), Specialized Information = Services=20 (accessed, December, 1998)=20
Richardson, M (1992), Dictionary of Substances and their Effects, = Royal=20 Society of Chemistry, Clays Ltd, England.=20
Sittig, M (1991), Handbook of Toxic and Hazardous Chemicals and=20 Carcinogens, 3rd edition, Noyes Publications, USA.=20
Technical Advisory Panel (1999), Final Report to the National = Environment=20 Protection Council.=20
US Department of Health and Human Services (1990), NIOSH Pocket = Guide to=20 Chemical Hazards, Publication No. 90-117.=20
Worksafe Australia (1996), Hazardous Substance Sulphur dioxide = (accessed,=20 March, 1999)

There is more information that may be useful in understanding some of = the=20 issues surrounding the NPI.

Ba= ckground=20 information