Why does the bathroom smell bad on rainy days?

In rainy days, the humidity and air pressure increase, resulting in poor ventilation and exhaust, and a large number of odors will overflow.

Factors:

1

The traditional floor drain only realizes the drainage function and has no sealing function.

Water seal and return bend can't prevent odor from flowing back.

2

The floor drain chosen for the bathroom decorated by myself doesn't even have a water seal.

Qualified floor drain can't prevent odor from flowing back at all.

three

Most of the newly-built buildings even cancel the waterproof bend, and the odor is more serious.