Why don’t you contact your board of health?
Methane gas going unchecked can cause cancer and other problems problems. Short term head ache dizziness and fainting PLUS it is highly explosive
What makes you think its ONLY Methane gas your being exposed to?
methane
a colorless odorless flammable gaseous hydrocarbon CH4 that is a product of decomposition of organic matter
Most of the “sewer gases” have been linked to several forms of cancer and other fatal dieases like