Laboratory determination of gravimetric correction factors for real-time area measurements of electronic cigarette aerosols: Part 2

Abstract

The popularity and widespread of electronic cigarettes (ECIGs) have warranted a necessity for monitoring different populations directly or indirectly exposed to particulate matter (PM) from ECIGs. To accurately estimate exposure to aerosols from ECIGs, it is important to correctly measure the concentration of aerosols. Real-time aerosol monitors are usually based on optics that provides biased measurements that are adjusted using filter correction factors. In addition, low-cost aerosol sensors have become popular that allow widespread of these sensors and can estimate ECIG aerosol exposure after calibration. Therefore, this study determined the filter correction factors for three aerosol monitors (MiniWRAS, pDR, and SidePak) based on exposure to six ECIG brands and two particle sizes (PM₁ and PM_2.5). In addition, the GeoAir2 low-cost monitor was evaluated compared to filter corrected MiniWRAS measurements for these exposures. The study also evaluated the real-time measurements and mass median diameter (MMD) for each ECIG brand. The correction factors varied between aerosol monitors, ECIG brands and particle sizes, with ranges for PM_2.5 that span between 1.85 and 2.42 (MiniWRAS), 0.50 and 0.58 (pDR), and 0.24 and 0.28 (SidePak). The GeoAir2 underestimated the reference measurements but had a high correlation (r = 0.90 − 0.94), showing that the monitor can be effectively calibrated to provide good estimates. The real-time average PM_2.5 measurements differed between aerosol instruments with concentrations that ranged between 1398 and 3706 μg/m³ (MiniWRAS), 5479 and 16,825 μg/m³ (pDR), and 9783 and 29,808 μg/m³ (SidePak). Finally, the MMD values spanned between 0.45 and 0.80 μm based on the MiniWRAS measurements. The differences between the raw real-time measurements for the aerosol monitors show the necessity for developing filter correction factors to accurately measure ECIG exposure.

Copyright © 2023 American Association for Aerosol Research

Graphical Abstract

Editor:

• Mark Swihart

Disclosure statement

Eric Soule is named on a patent application for a smartphone app that determines electronic cigarette device and liquid characteristics.

Additional information

Funding

This research is supported by grant number R15ES032138 from the National Institute on Environmental Health Sciences of the National Institutes of Health. Part of E.S.’s efforts is also supported by grant numbers U54DA036105 from the National Institute on Drug Abuse of the National Institutes of Health and the Center for Tobacco Products (CTP) of the U.S. Food and Drug Administration. The content is solely the responsibility of the authors and does not necessarily represent the views of the NIH or the FDA.