Acid deposition, commonly known as acid rain, poses a significant threat to stone sculptures, causing erosion, discoloration, and structural damage over time. To safeguard these valuable artworks, several effective strategies can be implemented.

1. Apply Protective Coatings: Use water-repellent or acid-resistant coatings like siloxane or fluoropolymer-based sealants. These barriers reduce direct contact between acidic pollutants and the stone surface.

2. Regular Cleaning: Gently clean sculptures with pH-neutral solutions to remove acidic deposits before they penetrate the stone. Avoid abrasive tools that could scratch the surface.

3. Environmental Controls: Install shelters or relocate sculptures indoors to minimize exposure to polluted air. For outdoor pieces, consider positioning them under roofs or in less polluted areas.

4. Monitoring and Maintenance: Conduct routine inspections to detect early signs of damage. Prompt repairs can prevent further deterioration.

5. Use Alkaline Treatments: Neutralize acidic residues by applying mild alkaline solutions, such as calcium hydroxide, to counteract the effects of acid deposition.

By combining these methods, stone sculptures can be preserved for future generations, maintaining their artistic and historical integrity despite environmental challenges.