You need organic vapor respirator cartridges (don't ask me to explain it, that's all I know about them). You can probably get them wherever you got your mask, or larger hardware stores may have them that fit. My mask is a 3M as well, but they make a bunch of different kinds. Here is a link to the organic vapor respirators on 3M's site, and the 5000 series is the one I have. I got mine at Lowes and they have the cartridges there as well. (It's a long link, hope it works OK)
http://products3.3m.com/catalog/us/en001/home_leisure/-/node_GSYD29Z4QFbe/root_GST1T4S9TCgv/vroot_GSHCV1ZFXKge/gvel_V11LLW3HL1gl/theme_us_homeleisure_3_0/command_AbcPageHandler/output_html