title: Influence of moisturizer and relative humidity on human emissions of fluorescent biological aerosol particles.
abstract: Utilizing the ultraviolet light-induced fluorescence (UV-LIF) measurement technique as embodied in the Waveband Integrated Bioaerosol Sensor (WIBS-4A), we evaluated the fluorescent particle emissions associated with human shedding while walking in a chamber. The mean emission rates of supermicron (1-10 μm) fluorescent particles were in the range 6.8-7.5 million particles per person-h (~0.3 mg per person-h) across three participants, for conditions when the relative humidity was 60%-70% and no moisturizer was applied after showering. The fluorescent particles displayed a lognormal distribution with the geometric mean diameter in the range 2.5-4 μm and exhibited asymmetry factors that increased with particle size. Use of moisturizer was associated with changes in number and mass emission rates, size distribution, and particle shape. Emission rates were lower when the relative humidity was reduced, but these differences were not statistically significant.
authors.affiliation: School of Civil and Environmental Engineering, Nanyang Technological University, Singapore, Singapore.|Berkeley Education Alliance for Research, Singapore, Singapore.
authors.forename: J
authors.initials: J
authors.lastname: Zhou
authors.affiliation: School of Civil and Environmental Engineering, Nanyang Technological University, Singapore, Singapore.
authors.forename: W
authors.initials: W
authors.lastname: Fang
authors.affiliation: School of Civil and Environmental Engineering, Nanyang Technological University, Singapore, Singapore.
authors.forename: Q
authors.initials: Q
authors.lastname: Cao
authors.affiliation: Interdisciplinary Graduate School, Nanyang Technological University, Singapore, Singapore.|Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore, Singapore.
authors.forename: L
authors.initials: L
authors.lastname: Yang
authors.affiliation: School of Civil and Environmental Engineering, Nanyang Technological University, Singapore, Singapore.|Berkeley Education Alliance for Research, Singapore, Singapore.|Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore, Singapore.
authors.forename: V W-C
authors.initials: VW
authors.lastname: Chang
authors.affiliation: Berkeley Education Alliance for Research, Singapore, Singapore.|Department of Civil and Environmental Engineering, University of California, Berkeley, CA, USA.
authors.forename: W W
authors.identifier: 0000-0001-5645-3357
authors.initials: WW
authors.lastname: Nazaroff
mesh_terms: D000328:Adult; D000336:Aerosols / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D044466:Asian People; D004784:Environmental Monitoring / Q000379:methods; D005260:Female; D005453:Fluorescence; D006801:Humans; D006813:Humidity; D010316:Particle Size; D063465:Skin Cream; D014495:Universities; D014885:Waxes / Q000378:metabolism*
chemical_list: D000336:Aerosols; D014885:Waxes; C034743:jojoba wax
keywords: Waveband Integrated Bioaerosol Sensor; fluorescence; occupancy; particle shape; skin; source strength