Bronze sculptures, renowned for their durability and timeless beauty, face unique challenges in environments with high nitrogen oxide (NOx) levels. Nitrogen oxides, common pollutants from vehicle emissions and industrial processes, can accelerate corrosion and tarnishing of bronze surfaces. Over time, these pollutants react with moisture in the air to form nitric acid, which etches the metal and dulls its patina.

However, bronze's inherent corrosion resistance offers some protection. The alloy's copper content forms a protective oxide layer, slowing degradation. Regular maintenance, such as wax coatings or specialized sealants, can further shield sculptures from NOx exposure. In heavily polluted urban areas, placing sculptures under protective coverings or indoors may be necessary to preserve their integrity.

Art conservators recommend frequent inspections to detect early signs of damage. Gentle cleaning with pH-neutral solutions helps remove acidic deposits without harming the metal. By understanding these environmental threats, cities and collectors can better protect bronze artworks for future generations.