sulfur dioxide

American  

noun

Chemistry.

1. a colorless, nonflammable, water-soluble, suffocating gas, SO 2 , formed when sulfur burns: used chiefly in the manufacture of chemicals such as sulfuric acid, in preserving fruits and vegetables, and in bleaching, disinfecting, and fumigating.

---

sulfur dioxide Scientific  

1. A colorless, poisonous gas or liquid with a strong odor. It is formed naturally by volcanic activity, and is a waste gas produced by burning coal and oil and by many industrial processes, such as smelting. It is also a hazardous air pollutant and a major contributor to acid rain. Chemical formula: SO ₂ .

---

Etymology

Origin of sulfur dioxide

First recorded in 1865–70

Example Sentences

See Examples For:

sulfur dioxide

The agency also refused to assign any benefits to the reduction of pollutants like nitrogen oxides and sulfur dioxide.

From Slate ● Aug. 2, 2026

Its emissions of the pollutant sulfur dioxide exceeded those of 43 states last year as power demand surged, fueling residents’ concerns about the air they are breathing.

From The Wall Street Journal ● May 28, 2026

Still, Parish and a handful of other plants remain top producers of sulfur dioxide, according to a Wall Street Journal analysis of years of EPA data.

From The Wall Street Journal ● May 21, 2026

Freeport spent $250 million on improvements completed in 2017 to better control sulfur dioxide emissions.

From Salon ● May 10, 2026

The pungent gas, sulfur dioxide, S02, is present in trace amounts in the lower atmosphere.

From "Cosmos" by Carl Sagan