Park chairs are designed to resist algae growth through a combination of materials, design features, and maintenance practices. Here’s how they stay algae-free:

1. Material Selection: Many park chairs are made from aluminum, treated wood, or plastic with anti-microbial additives. These materials are naturally resistant to moisture and algae.

2. Non-Porous Surfaces: Smooth, non-porous surfaces prevent water retention, reducing the damp conditions algae need to thrive.

3. UV-Resistant Coatings: Some chairs have UV-resistant or anti-algae coatings that inhibit organic growth and prolong durability.

4. Proper Drainage: Slatted or perforated designs allow water to drain quickly, minimizing stagnant moisture.

5. Regular Maintenance: Parks often clean chairs periodically to remove dirt and organic debris that could foster algae.

By combining these strategies, park chairs remain functional and aesthetically pleasing even in humid environments.