Amredl S l Yol; 4703 A_te Pateamun Piete Prinlcd Gr-Jl Ritt EPA clloxthin ) Pulana EXPERIMENTAL FILTRATION EFFICIENCIES FOR LARGE PORE NUCLEPORE FILTERS fnd} 0f 4 H. BuzzARD Enginecring Scictcc Duke Univcrsity, Deparimcnt or Mcchanical Jnd Naleriai Durkam NC 27706, USA and P BELL ivant} Environmicital Scicikes Kearcb Lacnrtory Envtronte (u Proleclicn Rereamch ARency Tulanel Pak NC 27711,USA Decembcr 19731 URCGCu4 Expcrimental fltration AEnct dala Walt collecicdin elort wahJite imoaction mod-l prewowly dcrcionedand pICcnicd Usinz sampler with porc cumetct Nuc cpore Iltcr , mencured [or bolh liquid and solid acresol: ovcr collcc 10] cllcictcic YLr sizd Taned of 2 good agrccment with tha impaclion model; houever, datz lor the Dilt (ar tnc k duid acrasolehowed snlid acrosol indicaled c Incdcl pnicciibl Oycr couccuon clliccnCy Than picdiclco Jiqu d aerosol data validatc Incinpiction modcl Inc solid neroso] dutaindicle DarltcIc bounce Icanirainnicalsuhscqueni imnachind wndercorc Dirliclecaniunc 44 pr ohicm be dcl WL I Nuclenont ezeacleclive 6lice Kuac INTRODUCTION Current needs in the field of air pollution monitoring have prompted several investigators Phillips, 1974, 1975; consider thc size seleclive characler ol Nuclepore surlaces (Melo und [978} The simplicity ol assembling Cahill al, 1977 Parker et al, 1977 and John llecting stacked scries of size selective Nucleporc surlaces makes this an ideal means lor co atmosphcric   particulate Parker   and Buzzard (1978) [ractionated samples maltcr, prescnted acrosol particles upon thcorctical modcl for tnc impacton mcchanism Nuclepore surlace and show theorctical collection elliciencies based the hypothesis that uOn particles which impact upon the filter surlace arc captured: This hypothesis scems plausible in the case sticky Or wet acrosol but may be Suspect in the case of dry or solid aerosols The experimental data of Parker and Buzzard were not conclusive,andanattempt Inadu limited amount in the present work to improve upon the experimental data data was also collected on the loading charactcristics of the filter, EXPERIMENTAL PROCEDURES Using diametcr Nuclepore surface primary filtcr and 0.4 pm pore POTe Ghier, diamcicr Nuclcpore surlacc as collection  elliciencics wete sccondary back-VP measured for both liquid and solid acrosols with particle diameters ranging from pm. All particles not captured by the primary flter were asSumed captured by the Secordary filter. Collcction efficiencies WErt determined for the primary filter. Particles were collected by face velocity of 10 and 20 cm scc Face velocity is defined as the sampler operating at dow rate divided by thc tota] frontal arca of the filtcr; Both acrosols valumeitic WcTO vibrating orifice gcnerator; as described by Berglund and Liu (1973},and generated using 1 generaled from oleic acid equipped with 20 ,I orilice The liquid aerosol and in solution witb mixture of four parts 95% ethyl alcohol and part distilled Wale onc satisfactory solid aerosol getierate The diliculty seemed dillicult Voltie rclated the sclection of the proper dyc material and thc appropriate solvcnt: Neither grade methylene blue (supplied by Fisher Scientific) laboratory nor tcchnical Erade
Amredl S l Yol; A_te Pateamun Piete 4703 Prinlcd Gr-Jl Ritt EPA clloxthin ) Pulana EXPERIMENTAL FILTRATION EFFICIENCIES FOR LARGE PORE NUCLEPORE FILTERS fnd} 0f 4 H. BuzzARD Deparimcnt or Mcchanical Enginecring Jnd Naleriai Scictcc Duke Univcrsity, Durkam NC 27706, USA and P BELL Environmicital Scicikes Kearcb Lacnrtory Envtronte (u Proleclicn ARency Rereamch Tulanel Pak NC 27711,USA ivant} URCGCu4 Decembcr 19731 AEnct Expcrimental fltration dala Walt collecicdin elort wahJite imoaction mod-l prewowly dcrcionedand pICcnicd Usinz sampler with porc cumetct Nuc cpore Iltcr , collcc 10] cllcictcic YLr mencured [or bolh liquid and solid acresol: ovcr sizd Taned of 2 Dilt (ar tnc k duid acrasolehowed good agrccment with tha impaclion model; houever, datz lor the snlid acrosol indicaled pnicciibl Oycr couccuon clliccnCy Than picdiclco c Incdcl Jiqu d aerosol data validatc Incinpiction modcl Inc solid neroso] dutaindicle DarltcIc bounce Icanirainnicalsuhscqueni imnachind wndercorc Dirliclecaniunc 44 pr ohicm be dcl WL I Nuclenont Kuac ezeacleclive 6lice INTRODUCTION Current needs in the field of air pollution monitoring have prompted several investigators consider thc size seleclive characler ol Nuclepore surlaces (Melo und Phillips, 1974, 1975; Cahill al, 1977 Parker et al, 1977 and John [978} The simplicity ol assembling stacked scries of size selective Nucleporc surlaces makes this an ideal means lor co llecting [ractionated samples atmosphcric   particulate maltcr, Parker   and Buzzard (1978) prescnted thcorctical modcl for tnc impacton mcchanism acrosol particles upon Nuclepore surlace and show theorctical collection elliciencies based uOn the hypothesis that particles which impact upon the filter surlace arc captured: This hypothesis scems plausible in the case sticky Or wet acrosol but may be Suspect in the case of dry or solid aerosols The experimental data of Parker and Buzzard were not conclusive,andanattempt Inadu in the present work to improve upon the experimental data limited amount data was also collected on the loading charactcristics of the filter, EXPERIMENTAL PROCEDURES Using POTe diametcr Nuclepore surface primary filtcr and 0.4 pm pore diamcicr Nuclcpore surlacc as sccondary back-VP Ghier, collection  elliciencics wete measured for both liquid and solid acrosols with particle diameters ranging from pm. All particles not captured by the primary flter were asSumed captured by the Secordary filter. Collcction efficiencies WErt determined for the primary filter. Particles were collected by  sampler operating at face velocity of 10 and 20 cm scc Face velocity is defined as the valumeitic dow rate divided by thc tota] frontal arca of the filtcr; Both acrosols WcTO generated using vibrating orifice gcnerator; as described by Berglund and Liu (1973},and equipped with 20 ,I orilice The liquid aerosol generaled from oleic acid and in solution witb mixture of four parts 95% ethyl alcohol and onc part distilled Wale Voltie satisfactory solid aerosol dillicult getierate The diliculty seemed rclated the sclection of the proper dyc material and thc appropriate solvcnt: Neither laboratory Erade nor tcchnical grade methylene blue (supplied by Fisher Scientific) 1