and the source of the pollution introducing polluted air into the chemical filter reacting pollutant molecules with the high surface area metal and introducing filtered air to the electronic equipment application_number US 81196985 A description referring to the drawing wherein like numerals of reference designate like elements throughout a piece of electronic equipment which is to be protected from pollutants in the atmosphere is depicted in fig1 in particular a hard disc drive 10 is shown comprising a disc 12 mounted on a shaft 14 which is rotated by a motor 16 the motor 16 is controlled by electronic controller 18 a housing 20 surrounds the hard disc 12 forming a chamber 21 a seal 22 is provided for the shaft 14 to pass through the housing 20 an internal particle filter 24 in the chamber 21 reduces particles generated by abrasion and the like during operation of the disc drive a head 26 spaced from the top surface of the disc 12 is used to write and read information stored in magnetic domains formed in the surface of the hard disc 12 the hard disc may comprise any material commonly used in the construction of such units for example an aluminum substrate coated with cobalt may be employed inasmuch as the disc drive unit is not a part of this invention the foregoing description is provided merely for illustration of one use to which the chemical filter of the invention may be put in accordance with the invention a chemical filter 30 is provided the chemical filter comprises a.