Modeled Respiratory Tract Deposition of Aerosolized Oil Diluents Used in Delta-9-THC-Based Electronic Cigarette Liquid Products

Details

• Personal Author:
  Fernandez E ; LeBouf, Ryan F. ; Ranpara, Anand ; Stefaniak, Aleksandr B. ; Willliams K
• Description:
  Electronic cigarette, or vaping, products (EVP) heat liquids ("e-liquids") that contain substances (licit or illicit) and deliver aerosolized particles into the lungs. Commercially available oils such as Vitamin-E-acetate (VEA), Vitamin E oil, coconut, and medium chain triglycerides (MCT) were often the constituents of e-liquids associated with an e-cigarette, or vaping, product use-associated lung injury (EVALI). The objective of this study was to evaluate the mass-based physical characteristics of the aerosolized e-liquids prepared using these oil diluents. These characteristics were particle size distributions for modeling regional respiratory deposition and puff-based total aerosol mass for estimating the number of particles delivered to the respiratory tract. Four types of e-liquids were prepared by adding terpenes to oil diluents individually: VEA, Vitamin E oil, coconut oil, and MCT. A smoking machine was used to aerosolize each e-liquid at a predetermined puff topography (volume of 55 ml for 3 s with 30-s intervals between puffs). A cascade impactor was used to collect the size-segregated aerosol for calculating the mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD). The respiratory deposition of EVP aerosols on inhalation was estimated using the Multiple-Path Particle Dosimetry model. From these results, the exhaled fraction of EVP aerosols was calculated as a surrogate of secondhand exposure potential. The MMAD of VEA (0.61 µm) was statistically different compared to MCT (0.38 µm) and coconut oil (0.47 µm) but not to Vitamin E oil (0.58 µm); p < 0.05. Wider aerosol size distribution was observed for VEA (GSD 2.35) and MCT (GSD 2.08) compared with coconut oil (GSD 1.53) and Vitamin E oil (GSD 1.55). Irrespective of the statistical differences between MMADs, dosimetry modeling resulted in the similar regional and lobular deposition of particles for all e-liquids in the respiratory tract. The highest (approximately 0.08 or more) fractional deposition was predicted in the pulmonary region, which is consistent as the site of injury among EVALI cases. Secondhand exposure calculations indicated that a substantial amount of EVP aerosols could be exhaled, which has potential implications for bystanders. The number of EVALI cases has declined with the removal of VEA; however, further research is required to investigate the commonly available commercial ingredients used in e-liquid preparations. [Description provided by NIOSH]
• Subjects:
  Aerosols Electrical Equipment And Supplies Lung Lung Diseases Occupational Health Particulate Matter Respiratory System Respiratory Tract Diseases Safety Smokers Solvents Tobacco Products

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• Keywords:
  Author Keywords: E-cigarette Cigarette Smoking Electronic Devices EVALI Lung Deposition Lung Disorders Oils Particle Size Particle Size Distributions Particulates Pulmonary System Disorders Respiratory Irritants Respiratory System Disorders Secondhand Exposure Estimates Secondhand Smoke Vapors Vitamin E Acetate

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• ISSN:
  2296-2565
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  RHD - Respiratory Health Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  9
• NIOSHTIC Number:
  nn:20064071
• Citation:
  Front Public Health 2021 Nov; 9:744166
• Contact Point Address:
  Ryan F. LeBouf, Respiratory Health Division, National Institute for Occupational Safety and Health, Morgantown, WV, United States
• Email:
  rlebouf@cdc.gov
• CAS Registry Number:
  2H-1-Benzopyran-6-ol, 3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-, 6-acetate (CAS RN 7695-91-2)
• Federal Fiscal Year:
  2022
• NORA Priority Area:
  Services
• Peer Reviewed:
  True
• Source Full Name:
  Frontiers in Public Health
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:c6325c37dd52a7147341e9c32ea02c2c167b3b5dc7029830a6f808fcfd1911766b7104a934d71e76b54bfee5a3ea92b79cbe7824763429f18550f74ea37cbb75
• Download URL:
  https://stacks.cdc.gov/view/cdc/222597/cdc_222597_DS1.pdf
• File Type:
  [PDF - 751.52 KB ]