Atlas Copco Air Compressor Untreated compressed air contains moisture, aerosols and dirt particles that can damage your system and contaminate your end product. Atlas Copco’s G-series compressors provide the clean, dry air that improves reliability, avoids costly downtime and safeguards your products. Compared to piston compressors, the G offers reduced energy consumption and high efficiency. The rotary screw technology minimizes vibrations for silent operation at the lowest initial investment.