A method for reducing particulates in the air comprising spraying a composition into the air, wherein said composition comprises: a) 0.001% to 1%, by weight of the composition, of a zwitterionic polymer b) a propellant comprising a compressed gas; and c) an aqueous carrier; wherein said polymer aggipmerates particulates in the air when said composition contacts particulates in the air, wherein the droplets of the sprayed composition have a mean particle size from 10 μm to 100 μm wherein said zwitterionic-polymer comprises, in the form of polymerized units: a) at least a monomer compound of general formula I: in which R 1 is a hydrogen atom, a methyl or ethyl group; R 2, R 3, R 4, R 5 and R 6, which are identical or different, are linear or branched C1 -C6, alkyl, hydroxyalkyl or aminoalkyl groups; m is an integer from 0 to 10; n is an integer from 1 to 6; Z represents a --C O-- or --C NH-- group or an oxygen atom; A represents a (CH 2) p group, p being an integer from 1 to 6; B represents a linear or branched C2 -C12, polymethylene chain optionally interrupted by one or more heteroatoms or heterogroups, and optionally substituted by one or more hydroxyl or amino groups; X, which are identical or different, represent counterions; and b) at least one hydrophilic monomer carrying a functional acidic group which is copolymerizable with (a) and which is capable of being ionized in the application medium; c) optionally at least one monomer compound with ethylenic unsaturation with a neutral charge which is copolymerizable with (a) and (b). a) 0.001% to 1%, by weight of the composition, of a zwitterionic polymer b) a propellant comprising a compressed gas; and c) an aqueous carrier; wherein said polymer aggipmerates particulates in the air when said composition contacts particulates in the air, wherein the droplets of the sprayed composition have a mean particle size from 10 μm to 100 μm wherein said zwitterionic-polymer comprises, in the form of polymerized units: a) at least a monomer compound of general formula I: in which R 1 is a hydrogen atom, a methyl or ethyl group; R 2, R 3, R 4, R 5 and R 6, which are identical or different, are linear or branched C1 -C6, alkyl, hydroxyalkyl or aminoalkyl groups; m is an integer from 0 to 10; n is an integer from 1 to 6; Z represents a --C O-- or --C NH-- group or an oxygen atom; A represents a (CH 2) p group, p being an integer from 1 to 6; B represents a linear or branched C2 -C12, polymethylene chain optionally interrupted by one or more heteroatoms or heterogroups, and optionally substituted by one or more hydroxyl or amino groups; X, which are identical or different, represent counterions; and b) at least one hydrophilic monomer carrying a functional acidic group which is copolymerizable with (a) and which is capable of being ionized in the application medium; c) optionally at least one monomer compound with ethylenic unsaturation with a neutral charge which is copolymerizable with (a) and (b). a) at least a monomer compound of general formula I: in which R 1 is a hydrogen atom, a methyl or ethyl group; R 2, R 3, R 4, R 5 and R 6, which are identical or different, are linear or branched C1 -C6, alkyl, hydroxyalkyl or aminoalkyl groups; m is an integer from 0 to 10; n is an integer from 1 to 6; Z represents a --C O-- or --C NH-- group or an oxygen atom; A represents a (CH 2) p group, p being an integer from 1 to 6; B represents a linear or branched C2 -C12, polymethylene chain optionally interrupted by one or more heteroatoms or heterogroups, and optionally substituted by one or more hydroxyl or amino groups; X, which are identical or different, represent counterions; and R 1 is a hydrogen atom, a methyl or ethyl group; R 2, R 3, R 4, R 5 and R 6, which are identical or different, are linear or branched C1 -C6, alkyl, hydroxyalkyl or aminoalkyl groups; m is an integer from 0 to 10; n is an integer from 1 to 6; Z represents a --C O-- or --C NH-- group or an oxygen atom; A represents a (CH 2) p group, p being an integer from 1 to 6; B represents a linear or branched C2 -C12, polymethylene chain optionally interrupted by one or more heteroatoms or heterogroups, and optionally substituted by one or more hydroxyl or amino groups; X, which are identical or different, represent counterions; and b) at least one hydrophilic monomer carrying a functional acidic group which is copolymerizable with (a) and which is capable of being ionized in the application medium; c) optionally at least one monomer compound with ethylenic unsaturation with a neutral charge which is copolymerizable with (a) and (b).