Electronic cigarettes: product characterisation and design considerations

Abstract

Objective: To review the available evidence regarding electronic cigarette (e-cigarette) product characterisation and design features in order to understand their potential impact on individual users and on public health.

Methods: Systematic literature searches in 10 reference databases were conducted through October 2013. A total of 14 articles and documents and 16 patents were included in this analysis.

Results: Numerous disposable and reusable e-cigarette product options exist, representing wide variation in product configuration and component functionality. Common e-cigarette components include an aerosol generator, a flow sensor, a battery and a nicotine-containing solution storage area. e-cigarettes currently include many interchangeable parts, enabling users to modify the character of the delivered aerosol and, therefore, the product's 'effectiveness' as a nicotine delivery product. Materials in e-cigarettes may include metals, rubber and ceramics. Some materials may be aerosolised and have adverse health effects. Several studies have described significant performance variability across and within e-cigarette brands. Patent applications include novel product features designed to influence aerosol properties and e-cigarette efficiency at delivering nicotine.

Conclusions: Although e-cigarettes share a basic design, engineering variations and user modifications result in differences in nicotine delivery and potential product risks. e-cigarette aerosols may include harmful and potentially harmful constituents. Battery explosions and the risks of exposure to the e-liquid (especially for children) are also concerns. Additional research will enhance the current understanding of basic e-cigarette design and operation, aerosol production and processing, and functionality. A standardised e-cigarette testing regime should be developed to allow product comparisons.

Keywords: Electronic nicotine delivery devices; Nicotine; Non-cigarette tobacco products.

Figure 1

Typical e-cigarette configuration. This shows a wick/heater as aerosol generator, gauze saturated with e-liquid, a microprocessor (optional) to control operations and an LED (optional) to imitate a burning coal.

Figure 2

Basic e-cigarette operation. This flowchart outlines basic actions and functions to transform and deliver e-liquid-based aerosol.

Figure 3

Diffuser. This diagram shows multiple angled openings that increase aerosol dispersion and buccal cavity contact. The numbers reference descriptive text in the patent.

Figure 4

Communications features. This diagram shows bidirectional data transfer between the consumer, computer, pack, social networks and stakeholders. The numbers reference descriptive text in the patent.