There are various risks associated with moss on concrete, including:

1.Slipperiness: Moss may make concrete surfaces incredibly slick, particularly when wet, which raises the possibility of slips and falls.

2.Surface damage: Over time, moss’s root-like structures can infiltrate concrete, causing surface damage that can result in cracks and concrete deterioration.

3.Moss can leave concrete surfaces stained, giving them a dirty, unattractive appearance.

4.Allergies: Moss can release spores that, in some people, cause allergies and respiratory issues.

5.Moss can attract pests such as insects and rats, which can further harm the concrete surface and the surroundings.

Regular moss removal from concrete surfaces and preventative measures like better drainage and more sunlight exposure are necessary to avoid these risks.