In one example, an inkjet web printer includes: an arched printing unit and an aerosol control system. The printing unit has a series of printheads arranged along an arc and multiple rollers to support a print substrate web along the arc through a print zone adjacent to each printhead. The aerosol control system has a vacuum duct through which air may be sucked away from the web leaving a print zone adjacent to one of the printheads and a pressure duct through which air may be blown on to the web leaving the print zone. The pressure duct is positioned downstream from the vacuum duct and configured to blow air diagonally upstream directly on to the web at the same location the vacuum duct is to suck air away from the web.