A portable dry scrubber comprises a gas flow control module comprising a gas receiving unit that receives inflow of gas from surrounding atmosphere or from a gas source, a gas processing module that removes hazardous matter from the gas flowed in through the gas receiving unit and a connection module that connects the gas flow control module detachably to the gas processing module. The connection module comprises quick coupling device that establishes and disassembles a gas flow passage between the gas flow control module and the gas processing module. Example of the quick coupling device is a quick release vacuum flange that engages with a connecting flange of the gas flow control module.