Intro to Sulfur Dioxide Gas
Sulfur dioxide is a chemical compound belonging to a family of sulfur oxides with the formula SO2. Sulfur dioxide is a colorless gas, has an irritating, pungent and suffocating odor, and is very toxic. As a result, SO2 poses a significant threat in many workplaces. Even at low concentrations, prolonged exposure can lead to breathing difficulties and damage to the respiratory tract. Additionally, sulfur dioxide is very reactive and often combines with other compounds in the atmosphere. These compounds can increase acid rain or haze— both are dangerous to health.
SO2 is primarily produced from the burning of sulfur-containing fuels, such as coal. Endogenous sulfur dioxide is produced naturally by volcanic activity and biological processes. However, the primary source of anthropogenic SO2 emissions is the burning of fossil fuels, particularly coal-fired power plants. When coal is burned, sulfur impurities in the coal react with oxygen to form SO2 gas. This gas is then released into the atmosphere, where it can contribute to air pollution, acid rain, and respiratory problems.
SO2 is highly reactive and can combine with water vapor in the atmosphere to form sulfurous acid, a major component of acid rain. It can also react with other pollutants to form sulfate aerosols and sulfate particles, which can reduce visibility and harm human health.
In addition to its role in air pollution, SO2 is also used in various industrial processes, such as the production of sulfuric acid, paper, and textiles. Sulfide ores, which contain sulfur compounds, are often roasted to extract metals, and this process releases SO2 as a byproduct.
While SO2 has some industrial applications such as in the production of sulfuric acid and as a food preservative in its liquid form, its harmful effects on human health and the environment make it a significant environmental concern. Strict regulations and pollution control technologies are necessary to reduce SO2 emissions and protect public health.
Gas Characteristics
- Colorless
- Heavier than air
- Suffocating, irritating, pungent odour (often described as "burning matchsticks")
- If heated, can explode
- VERY toxic
- Corrosive impact on the respiratory tract
- Can make breathing quite difficult
- Reacts violently with halogens & strong bases
- Also known as sulfurous anhydride and sulfur(IV) oxide and can be spelled sulphur dioxide.
- CAS 7446-09-5
Industrial SO2 hazards and sources
- Any industry where it is present as a by-product, including copper smelting & power plants
- Pulp and paper mills
- Chemical processing
- Metal smelting and processing
- Oil and petroleum refineries
- Manufacturing of fertilizers
- Manufacturing of sulfuric acid
- Cement manufacturing
- Food and beverage processing
- Glass manufacturing
- Sewer and wastewater treatment
- Other industrial facilities burning fossil fuels or coal
- Can be generated endogenously in mammals
High concentrations of SO2 can affect lung function, worsen asthma attacks, and worsen existing heart disease in sensitive groups.
(National Park Service)High Risk Scenarios
- As sulfur dioxide exposure can make breathing difficult, those with asthma are particularly at risk.
- Naturally occurs in smaller quantities in volcanoes and volcanic eruptions.
- Any industrial process that burns coal or petroleum.
- Automobiles, ships, trains and other fossil-fuel burning methods of transportation will emit it.
- Heavy equipment that burns fuel with a high sulfur content is also a common source.
- Petroleum production and oil refining have numerous process that can lead to sulfur dioxide exposure.
- Nearly all production processes involving metals pose a threat (aluminum production, steel production, forging, molding and core making, smelting copper or lead, metal extraction and refining, etc.)
Confined space entry hazard: sulfur dioxide is heavier than air so can accumulate in the lower sections of confined spaces.
FIRST AID
- If INHALED, move the impacted person to fresh air, and prevent them from moving around unnecessarily.
- If breathing is difficult, trained staff should provide emergency oxygen.
- Call poison control or a doctor IMMEDIATELY and transport the victim to a hospital.
- If SKIN CONTACT is made, gently apply lukewarm water to the impacted area for 5 minutes and call poison control/a doctor (if the affected area is the eyes, ensure the victim's eyelids are open).
IF ACCIDENTALLY RELEASED
- Wear chemical-protective clothing, as well as safety goggles and a face shield.
- If you are wearing the necessary safety equipment, remove the sulphur dioxide from the area if possible.
- Ventilate the impacted area as much as possible.
- Try and knock down sulphur dioxide gas with fog or fine water spray - be aware, the resulting sulfuric acid is corrosive and toxic.
- If the leak is very large or difficult to control, contact local emergency services.