The air was saturated with the acrid and unpleasant odor of sulphurous acid.

Good Sulphur dioxide, yeah we get sulphurous acids and sulphuric acids.

In 1905, a chemical company erected a large acid plant for the manufacture of sulphuric and sulphurous acid.

(British English: sulphurous acid) is the chemical compound with the formula HSO.

He proposed a method for combining sulphurous acid gas (sulphur dioxide) directly with oxygen, using finely divided platinum, and absorbing the resultant sulphur trioxide on moistened pebbles.

In 1867, Benjamin Tilghman, an American chemist, discovered that sulphurous acid (H2SO3) dissolved the lignin in wood, leaving a residue of cellulose fibers.

In England, yet another product known as wood wool was produced by the chemical breakdown of wood strips by means of sulphurous acid, for use in such applications as absorbent material in surgical dressings.