Problems for Particulate Profs

Posted 6th December 2019 by Dave Cross
Researchers from the University of Bari and the National Institute of Health in Rome have published a paper looking at second-hand ultrafine particles. They express concerns, but this topic of investigation was roundly debunked by leading advocate Clive Bates five years ago.

This “study aims to evaluate the impact of e-cig second-hand aerosol on indoor air quality in terms of ultrafine particles (UFPs) and potential inhalation exposure levels of passive bystanders,” write the Italian authors.

Despite being welcomed by anti-vaping campaigners, the study only looked at aerosol produced by just two people. They studied and measured 15 different e-liquid characteristics in terms of the UFPs number, concentration, and size distribution. We are left to guess at what the undefined “natural ventilation” or a “realistic exposure scenario” entails.

They demonstrated that vaping produces particulates in orders or magnitude lower than smoking – but failed to differentiate on the type of particulates measured.

“In the size range 6-26 nm, particles concentration in e-cig second-hand aerosol were from 2- (Dp = 25.5 nm) to 3800-fold (Dp = 9.31 nm) higher than in tobacco smoke highlighting that particles exhaled by users and potentially inhaled by bystanders are nano-sized with high penetration capacity into human airways.”

If that sounds worrying then that was probably the aim as Clive Bates noted five years ago: “Opponents of e-cigarettes have determined that ‘ultrafine particles’ or ‘particulates’ are an issue they can work with. But this campaigning gambit, it turns out, involves a crude scientific sleight of hand.”

Vampire Vape

Stanton Glantz was one of the first to propose that particulates presented a problem, to which Clive quotes Dr Farsalinos saying: “However, this is a direct mis-presentation of evidence, since there is not even a single study indicating that particles emitted from e-cigarettes represent a risk factor for cardiovascular disease.”

“The important and obvious point for scientists and non-scientists alike is that it is not just the size of the particles that matters, but what they are made of. That is how reactive and toxic the surface chemistry is and whether they are liquid and likely to be easily absorbed or solid and likely to lodge in lung tissue. There is a big difference between the soot from diesel engines, emissions from power stations, photochemical smog or biomass burning (including the hot reactive organic particles in tobacco smoke) and the relatively benign components of an e-cigarette vapour droplet.”

Clive’s full article is linked below.


  • “Evaluation of Second-Hand Exposure to Electronic Cigarette Vaping under a Real Scenario: Measurements of Ultrafine Particle Number Concentration and Size Distribution and Comparison with Traditional Tobacco Smoke” by Palmisani et al. - [link]
  • “Scientific sleight of hand: constructing concern about ‘particulates’ from e-cigarettes”, Clive Bates – [link]

 Dave Cross
Article by Dave Cross
Freelance writer, physicist, karateka, dog walker