Deconstructing the “FOUR D’s” applied to air cabin air quality

Not only is the European Aviation Safety Agency (EASA) in denial, they are also delaying action by sponsoring further research. They deny any health effects from fume events, despite the reality of sick people resulting from such events with acute illness proximate to exposure events, and with longer-term effects likely in some cases; they altogether dismiss “aerotoxic syndrome” as even possible. Their linear reductionist approach, invoking the argument of low-level OPC in cabins, appears to provide them the basis for ruling out any human health effects from fume events, and also from low-level chronic exposure to cabin air even in the absence of acute fume events.

Their bias toward finding no-effect is apparent in their project description using words such as “misguided” in ruling out alternative hypotheses in their study. One is left wondering if, with their approach, they will measure the most relevant exposures and endpoints.

Recent wisdom shared from Greenberg (2017) indicates that, under the Precautionary Principle,

the discharge of gases and fumes into an aircraft cabin can be justified only after prior investigation finds the practice to be innocuous. The chemical cocktails to which passengers and crew are exposed will vary qualitatively and quantitatively, so that, even if a standard examination methodology has been employed, their effects need not be identical between incidents.

The obligation of the industry is to avoid supply-air contaminating cabin air. With the design of one aircraft more recently, the problem has been largely avoided. Given what is already known, while more research may be of interest to advance knowledge with greater precision in our estimates of effect, we have sufficient experience to act now to protect cabin crew, pilots, and passengers by engineering the problem out and acknowledging previous harms caused.

The German Airline Association’s Trade Group (BDL), among others, was invited to participate in a 2017 seminal conference on the topic in London, England. Their own position statement claims:

Regarding the topic of cabin air, it has repeatedly been stated in the past few years whether the health of the passengers and crews as well as the safety of the flight could be endangered by the penetration of burned oil residues into the cabin air. It is therefore important to the airlines to know whether there are actually reliable findings from scientific investigations that confirm these statements and whether there is a problem that neces-sitates changes in flight operations or the maintenance or manufacture of aircraft (BDL 2017).

If the BDL had seen a glaring inconsistency between its decision to not par-ticipate in the 2017 conference and with the above words, they may have aligned their actions with their words by sending a representative and some of the German aviation industry to participate in the conference. Instead, by boy-cotting or shunning an opportunity to have a seat at the table, the opportunity to advance science is denied. Science advances through transparent, open dis-cussion, and access to data.

The question now is: When will cabin air quality be rationally addressed, given that it has long been subjected to the “FOUR D’s”?

The International Joint Policy Committee of the Societies of Epidemiology (IJPC-SE)

The International Joint Policy Committee of the Societies of Epidemiology (IJPC-SE) works at the interface of research and policy. The IJPC-SE strives to bring clarity to the science of epidemiology, paving the way to rational evidence-based policy. It works to promote and protect public health by serving as an ethical and effective counterweight to the misuse of epidemiologic evidence.

The challenge in pursuing truth is in recognizing how evidence is generated and how junk science infiltrates the literature and confuses decision-making bodies. The IJPC-SE, with its global volunteer professional base of epidemiologists, can help in instances where science is being misused. Through its collective efforts, the IJPC-SE brings the benefit of a unified professional voice in the public interest. Other industries have been compelled to clean up their acts. With evidence in hand, the airline industry too would be compelled to relent.

The IJPC-SE is a not-for-profit consortium of 23 national and international volunteer, professional epidemiology organizations, spanning six continents, that have joined together to ensure health for all through ethical, independent, and transparent science. It works collaboratively and transparently to address health-related issues and minimize harm. It hosts forums and develops position statements and policy briefs with recommendations to protect and improve public health. Through its collective efforts, the IJPC-SE brings the benefit of a unified professional voice in the public interest.

Ultimately, rational policy will be influenced by evidence. The generation of evidence by trained scientists is expected to follow scientific and ethical principles such that valid science will result.

By persistently holding corporate leaders’ feet to the fire on their obligation to protect worker and passenger safety and health based on valid evidence, decency, common sense, and rational policy should eventually prevail.

The way forward

True democracy, through a well'informed public, underscored by an improved government science, technology, and innovation strategy should:

  • • Offer incentives to non-profit professional organizations in support of capacitybuilding to expose junk science, particularly where applied science works at the nexus of policy
  • • Introduce disincentives (i.e. regulatory penalties) for those engaging in producing junk science

We must also recognize that academia is a multi-billion dollar industry that fails to adequately address conflicting interests. At the end of the day, ethics is key to science and to public health. Without a serious and effective system of ethical oversight, evidence and public policy are being easily corrupted by vested interests. Overwhelming evidence of this has been provided by the tobacco industry, the asbestos industry, the fossil fuel industry, the chemical industry, the fast food industry, the mining industry, the sweetened beverage industry, and the lead industry; the list is long.

Concluding messages

  • • We all lose when the trajectory on which we find ourselves is flawed and unsustainable.
  • • A WIN - WIN - WIN outcome is most likely when the pursuit of truth is sought with a mind open to adapting to empirical realities.
  • • Powerful interests relentlessly manoeuver their way onto review panels, influence boards of our professional associations, and infiltrate the literature with junk science.
  • • Systemic, institutionalized bias enables science to conform to the dominant paradigm.
  • • Expert witness tensions arise between the plaintiff and defence sides of the argument in tort actions where the rubber hits the road concerning policy decisions.
  • • Uncertainty is inherent to science.
  • • Science strives to be value-neutral or value-free, but the human instrument is not.
  • • We must look first to ourselves when examining the current trajectory of influence in science, because causal inference is a function of who it is that is making the inference which, in turn, is a function of how we apply our scientific methods.


I strive for professional service in the public interest.

I served for a few years and until 2012 as an expert witness in litigation on behalf of plaintiffs, monies from which generally went into a University-managed research account.

As a professional legacy, I bankrolled the 1JPC-SE as a voluntary professional society for the years between 2011 and 2016, hoping that it might become an enduring counterbalance to ideological and moneyed influence in policies impacting health.

The IJPC-SE was one of the endorsers of the 2017 Aircraft Cabin Air Quality Conference.

I helped Dr Tsuda with editing his 2016 publication on thyroid cancer in relation to the Fukushima 2011 accident.


The International Joint Policy Committee of the Societies of Epidemiology (IJPC-SE) is, at time of going to press, undergoing a name-change to the International Network for Epidemiology in Policy (INEP). Re-branding will take place thereafter.


BDL. (2017) Progress Report. Quality of the Cabin air in Commercial Aircraft. Available at https://gcaqe.Org/wp-content/uploads/2017/l l/BDL_progress-report-English-Mar2017.pdf

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Greenberg, M. (2017) Personal communication.

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Ruff K. (2017) ‘Serving Industry, Promoting Skepticism, Discrediting Epidemiology’, Chapter 7 in: Corporate Ties that Bind: An Examination of Corporate Manipulation and Vested Interest in Public Health, edited by Walker M. J., 119-35; 482-5. New York, NY: Skyhorse Publishing.

Soskolne C. L. (2017) ‘Global, Regional and Local Ecological Change: Ethical, Aspects of Public Health Research and Practice’, Chapter 1 in: Ethics of Environmental Health, edited by Zolzer E, Meskens G. Routledge Studies in Environment and Health. London and New York, NY: Routledge, Taylor & Francis.

Tsuda T, Tokinobu A., Yamamoto E., Suzuki E. (2016) ‘Thyroid Cancer Detection by Ultrasound Among Residents Aged 18 Years and Younger in Fukushima, Japan: 2011 to 2014’, Epidemiology, 2016(27), 316-22.

Vaccarella S., Franceschi S., Bray E, Wild C. P., Plummer M., Dal Maso L. (2016) 'Worldwide Thyroid-cancer Epidemic? Tire Increasing Impact of Overdiagnosis’, The New England Journal of Medicine, 375, 614-17.

9 Tragic failures

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