The initial test will determine:• the challenge to Filters A and B (If the local environment is reasonable, the air delivered from the compressor may meet the specification with no further treatment. If there is heavy pollution, then a filter will be required.)• the output air quality from the system intermediate filters (Filters A and B)• any measurable contamination from the compressed air distribution pipework to the air being distributed Ongoing monitoring of the air will depend on the result of this test. If the system has no hydrocarbon challenge from the air, then one strategy is proposed, if the outside air provides a hydrocarbon challenge to the system an alternative monitoring approach is proposed (see Table 10.3).