['nent', 'which', 'comprises', 'only', 'a', 'small', 'percentage', 'of', 'the', 'aerosol', 'will', 'be', 'di-', 'rectly', 'related', 'to', 'the', 'surfacg', 'area', 'of', '-', 'the', 'particle', 'when', 'condensation', 'occurs', '[ie].', 'Me~S', '~r?', 'Where', 'Mc', 'is', 'the', 'mass', 'of', 'a', 'single', 'component,', 'S', 'the', 'surface', 'area', 'andr', 'the', 'radius', 'of', 'the', 'aerosol.', 'However,', 'the', 'total', 'mass', 'M,', 'of', 'an', 'aerosol', 'par-', 'ticle', 'is', 'a', 'direct', 'function', 'of', 'the', 'vol-', 'ume', '[ie]', 'M,', '~', 'Vd', '~', '1rd', 'where', 'V', 'is', 'the', 'volume', 'and', 'd', 'the', 'density', 'of', 'the', 'particle.', 'Assuming', 'the', 'density', 'of', 'all', 'particles', 'to', 'be', 'nearly', 'the', 'same', 'M,~V~r', 'it', 'follows', 'that', 'the', 'total', 'filter', 'effi-', 'ciency', 'F,', 'is', 'a', 'function', 'of', 'M,', 'and', 'the', '’', 'filter', 'efficiency', 'for', 'any', 'component', 'Fe', 'is', 'a', 'function', 'of', 'Mc', 'F,~M,~1r', 'and', 'Fe', '~', 'Mc', '~', 'r?', 'therefore', '[Fc]?/?~', 'F,', '[if', 'compo-', 'nent', 'is', 'on', 'perimeter', 'of', 'cross', 'section]', 'Consequently,', 'a', 'filter,', 'whose', 'sur-', 'face', 'will', 'adsorb', 'or', 'react', 'with', 'phenol,', 'may', 'selectively', 'remove', 'phenol', 'from', 'both', 'the', 'vapor', 'and', 'particulate', 'phase', 'and', 'selectivities', 'greater', 'than', '20%', 'are', 'obtainable.', 'With', 'this', 'hypothesis', 'in', 'mind', 'sev-', 'eral', 'types', 'of', 'materials', 'were', 'evalu-', 'ated', 'as', 'selective', 'filters', '[1]', 'cellulose', 'acetates', '[2]', 'ethers', 'and', '[3]', 'oxazolidi-', '.', 'nones.', 'Cellulose', 'diacetate', 'had', 'previ-', 'ously', 'shown', 'some', 'selectivity', 'and', 'con-', 'sequently', 'cellulose', 'triacetate', 'was', 'evaluated.', 'Association', 'complexes', 'be-', 'tween', 'phenols', 'and', 'mono', 'ethers', 'had', 'been', 'studied', 'by', 'Bellamy,', '¢t', 'al.2', 'Be-', 'cause', 'of', 'the', 'relatively', 'high', 'vapor', 'pressures', 'of', 'the', 'simple', 'ethers', 'they', 'were', 'not', 'considered', 'as', 'filter', 'mate-', 'rials', 'but', 'polyethers', 'were', 'found', 'to', 'be', 'suitable.', 'Infrared', 'spectral', 'meas-', 'urements', 'on', 'solutions', 'of', 'the', 'poly-', 'ethers', 'and', 'phenol', 'in', 'carbon', 'tetra-', 'chloride', 'solution', 'indicated', 'strong', 'hy-', 'drogen', 'bond', 'formation', 'with', 'no', 'meas-', 'urable', 'concentration', 'of', 'unbonded', 'phenol', 'at', '2:1', 'ether-phenol', 'weight', 'ratios.', 'Poly', '[-N-vinyl-5-methy]-2-oxa-', 'zolidinone}]', 'and', 'a', 'copolymer', 'of', 'the', 'oxazolidinone', 'moiety', 'and', 'vinyl', 'acetate', 'form', 'stable', 'complexes', 'with', 'phenols', 'and', 'hence', 'were', 'evaluated', 'as', 'filter', 'materials.2', 'Before', 'data', 'were', 'collected', 'on', 'fil-', 'ters', 'a', 'number', 'of', 'possible', 'variables', '_', 'Were', 'evaluated', 'and', 'controlled', 'when', 'necessary.', 'The', 'tobacco', 'portion', 'of', 'all', 'cigarettes', 'was', 'of', 'the', 'same', 'tobacco', 'blend,', 'particle', 'size', 'and', 'moisture', 'con-', 'tent.', 'Cigarettes', '[85', 'mm.', 'with', 'filter]', 'were', 'smoked', 'under', 'the', 'same', 'condi-', 'tions', 'and', 'phenol', 'analyses', 'performed', 'by', 'a', 'gas', 'chromatographic', 'method.’', 'The', 'relative', 'standard', 'deviation', 'and', 'relative', 'error', 'of', 'the', 'method', 'were', '2%.', 'FIGURE', '-', 'I', 'EFFICIENCY', 'FOR', 'PARTICULATE', 'PHASE', 'Vs', 'EFFICIENCY', 'FOR', 'PHENOL', 'PERCENT', 'PARTICULATE', 'REMOVAL', '0', '10', '20', '30', '40', 'The', 'amount', 'of', 'plasticizer', '[glyce-', 'ryl', 'triacetate]', 'was', 'controlled', 'and', 'its', 'effect', 'on', 'selective', 'filtration', 'evalu-', 'ated,', 'Figure', '3.', 'It', 'is', 'presumed', 'that', 'the', 'change', 'in', 'phenol', 'removal', 'with', 'time', 'is', 'due', 'to', 'diffusion', 'of', 'the', 'glyceryl', 'triacetate', 'from', 'the', 'surface', 'of', 'the', 'fiber.', 'Consequently,', 'filters', 'which', 'incorporated', 'glycery]', 'triace-', ' ', 'INERT', 'FILTERS', '50', '60', '70', '80', 'PHENOL', 'REMOVED', 'tate', 'were', 'stored', 'under', 'controlled', 'conditions', 'and', 'evaluated', 'after', 'four', 'weeks.', 'Cellulose', 'acetate', 'filters', 'reflected', 'slight', 'differences', 'in', 'selectivity', 'with', 'degree', 'of', 'acetylation', 'and', 'surface', 'area', 'as', 'shown', 'in', 'Table', '32.', 'The', 'lack', 'of', 'selectivity', 'by', 'the', 'cel-', 'lulose', 'filter', 'reported', 'in', 'Table', '3', 'sig-', 'Table', '3', '°%,', 'Particulate', 'Removal', 'Sample', '*Cellulose', 'diacetate', '’', '8.2', 'denier', 'fiber', '46', '*Cellulose', 'diacetate', '~', '2.1', 'denier', 'fiber', '54', '**Cellulose', 'triacetate', '8.2', 'denier', 'fiber', '47', 'Cellulose', '69', '*', '38-39%,', 'acetyl', 'Od', 'S445,', 'acetyl', ' ', '°/,', 'Phenol', '%,', 'Selective', 'Removal', 'Removal', 'of', 'Phenol', '70']