The electret article comprises a polymer (1) and a performance enhancing chemical (2) wherein the article has a thermally stimulated discharge current (TSDC) spectrum having a peak with a width at half-height of less than 30[deg]C by test procedure 3. Independent claims are also included for the following: (a) a non-woven web containing the electret article as melt blown fibres; (b) the electret filter comprising the non-woven web of melt blown fibres and has an initial DOP penetration of less than 5% and an average 'minium at challenge' of above 200 mg by DOP filter web loading test procedure 1; (c) a respirator containing an electret filter comprising a non-woven web comprising (1) and (2); a support structure and cup-like member to fit over the mouth and nose; and which has a 'minimum at challenge' of over 400 mg DOP and has an exposed surface area of about 180 cm 2>; (d) an intermediate composition for making an electret filter comprising the non-woven fibrous web comprising polypropylene with a crystallinity index of less than 0.3 and (2) and has a charge density of 10 mC / m 2>;.