A VOC treatment apparatus is provided for treating substantially opaque VOCs and comprises a processing chamber (24) in which VOCs are treated; and a solar energy introducing device (8). The solar energy introducing device (8) comprises a tubular structure having a first end located external to the processing chamber (24) and having a first inlet (14) through which concentrated sunlight is received and a second inlet (16) through which a flow of substantially optically transmittant gas is received. The solar energy introducing device (8) has a second end (18) that opens into the processing chamber (24) and terminates in a nozzle providing an outlet for the substantially optically transmittant gas and the concentrated sunlight. In use the optically transmittant gas exits the second end of the device in a jet to create an optically transmittant zone in the substantially opaque VOCs within the processing chamber (24), in which zone the sunlight can travel.