title: Deposition efficiency of inhaled particles (15-5000 nm) related to breathing pattern and lung function: an experimental study in healthy children and adults.
abstract: Exposure to airborne particles has a major impact on global health. The probability of these particles to deposit in the respiratory tract during breathing is essential for their toxic effects. Observations have shown that there is a substantial variability in deposition between subjects, not only due to respiratory diseases, but also among individuals with healthy lungs. The factors determining this variability are, however, not fully understood.
  
  
  
  In this study we experimentally investigate factors that determine individual differences in the respiratory tract depositions of inhaled particles for healthy subjects at relaxed breathing. The study covers particles of diameters 15-5000 nm and includes 67 subjects aged 7-70 years. A comprehensive examination of lung function was performed for all subjects. Principal component analyses and multiple regression analyses were used to explore the relationships between subject characteristics and particle deposition.
  
  
  
  A large individual variability in respiratory tract deposition efficiency was found. Individuals with high deposition of a certain particle size generally had high deposition for all particles <3500 nm. The individual variability was explained by two factors: breathing pattern, and lung structural and functional properties. The most important predictors were found to be breathing frequency and anatomical airway dead space. We also present a linear regression model describing the deposition based on four variables: tidal volume, breathing frequency, anatomical dead space and resistance of the respiratory system (the latter measured with impulse oscillometry).
  
  
  
  To understand why some individuals are more susceptible to airborne particles we must understand, and take into account, the individual variability in the probability of particles to deposit in the respiratory tract by considering not only breathing patterns but also adequate measures of relevant structural and functional properties.
authors.affiliation: Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden, Ideon Gateway, Sheelevägan 27, SE-223 70, Lund, Sweden. jenny.rissler@ri.se.|Ergonomics and Aerosol Technology, Lund University, Box 118, SE-221 00, Lund, Sweden. jenny.rissler@ri.se.|NanoLund, Lund University, Box 118, SE-221 00, Lund, Sweden. jenny.rissler@ri.se.
authors.forename: Jenny
authors.identifier: 0000-0001-8650-4741
authors.initials: J
authors.lastname: Rissler
authors.affiliation: Ergonomics and Aerosol Technology, Lund University, Box 118, SE-221 00, Lund, Sweden.|NanoLund, Lund University, Box 118, SE-221 00, Lund, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Gudmundsson
authors.affiliation: Clinical Physiology and Nuclear Medicine, SE-205 02, Malmö, Sweden.
authors.forename: Hanna
authors.initials: H
authors.lastname: Nicklasson
authors.affiliation: Division of Nuclear Physics, Lund University, Box 118, SE-221 00, Lund, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Swietlicki
authors.affiliation: Clinical Physiology and Nuclear Medicine, SE-205 02, Malmö, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Wollmer
authors.affiliation: Ergonomics and Aerosol Technology, Lund University, Box 118, SE-221 00, Lund, Sweden.|NanoLund, Lund University, Box 118, SE-221 00, Lund, Sweden.
authors.forename: Jakob
authors.initials: J
authors.lastname: Löndahl
mesh_terms: D000328:Adult; D000368:Aged; D000393:Air Pollutants / Q000493:pharmacokinetics* / Q000633:toxicity; D000076103:Biological Variation, Individual; D002648:Child; D005260:Female; D006801:Humans; D019570:Inhalation Exposure / Q000009:adverse effects / Q000032:analysis*; D008168:Lung / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010316:Particle Size; D052638:Particulate Matter / Q000493:pharmacokinetics* / Q000633:toxicity; D025341:Principal Component Analysis; D012119:Respiration / Q000187:drug effects*; D012129:Respiratory Function Tests; D012137:Respiratory System / Q000187:drug effects / Q000378:metabolism; D014018:Tissue Distribution; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter
keywords: Aerosols; Airborne particles; Airway dead space; Individual variability; Inhalation; Lung dose; NanoSafety; Particle lung deposition; Respiratory tract deposition