Bronze sculptures, renowned for their durability and artistic appeal, face significant challenges in environments with high sulfur dioxide (SO₂) concentrations. SO₂, a common pollutant from industrial emissions and fossil fuel combustion, reacts with moisture to form sulfuric acid, accelerating corrosion. However, bronze's copper-tin alloy composition offers inherent resistance.

Initially, SO₂ exposure causes surface oxidation, forming a dark layer of copper sulfide. Over time, this reacts with carbon dioxide and water to create a stable green patina (basic copper sulfate), which acts as a protective barrier against further degradation. This natural patination process is why many outdoor bronze statues develop their iconic verdigris hue.

To enhance longevity, modern sculptures often undergo artificial patination or protective wax coatings. Regular maintenance, including cleaning and reapplication of inhibitors, further mitigates SO₂ damage. Despite these challenges, bronze remains a preferred medium for outdoor art due to its self-protecting patina and timeless aesthetic.