The following document was a company advise and procedure with DHL in 2007. Then the operator realized the potential dangers associated with fumes from the engines after numerous pilot reports and was among the first who installed filters on their Boeing 757 cargo airplanes. This filter is even officially approved by the EASA since 2010, as the Supplemental Type Certificate (STC) clearly indicates.
Apparently these filters currently have their limitations. It is reported that the air flow of the currently installed system is sufficient to support the cockpit with sufficient filtered air. If this would also apply for an entire passenger compartment is not yet known beyond doubt. According to the manufacturer of such filter systems it would nevertheless be feasible. But without “demand” from airlines and operators the filter developers and manufactures do not see any need to go through costly and lengthily design and certification processes.