3D Printer Air filter

Thought I'd put this up in case others are interested in their health. I know it's said that PLA fumes are pretty much harmless but I cant help thinking it's not a bad idea to try and reduce the intake. Whenever I start a printing run of a few objects I often get a burning at the back of my throat, might as well be on 40 a day. Down to description: I clad the printer in 3mm clear acrylic, making use of the bolt holes in the chassis. The front was made to detach easily. The top was fixed with clear silicon to give a bit of a seal. Cut a 30mm hole in the top piece together with 4 fixing holes and sandwiched it with these two models(filter side down). The fan is a 60mm 12 volt PC case fan with 50mm fixings. I threaded the four holes to take M5 cap head bolts. The whole thing was made to take 3M's face mask range of filters so I tried the 2091 first but it didn't have the desired effect. Then tried a 6055 and I couldn't smell a thing from the printer. Bliss no sore throat. The fan creates