Governments, Regulators & Airlines repeatedly say that there is no scientific evidence to prove contaminated air onboard aircraft is hazardous to human health. The U.K. Government claim that The Cranfield Study - 2011 which took samples from just 100 flights is sufficient evidence to prove that cabin air onboard aircraft is safe. (Over 1,400 flights take off and land at Heathrow alone each day)
https://dspace.lib.cranfield.ac.uk/bitstream/handle/1826/5305/AircraftCabinAirSamplingStudyPart1FinalReport%2020110420.pdf?sequence=1&isAllowed=y

This paper from the Committee on Toxicity is where the UK Government currently stand on the issue:
https://cot.food.gov.uk/sites/default/files/cot/cotpospapcabin.pdf

‘The Government has taken appropriate action on cabin air quality, and has conducted studies in an open and transparent way. The studies were reviewed by an independent committee of toxicology experts which, in turn, has published their conclusions’ (link above).
‘Their research and review helped to inform the current government position on cabin air.’ - Baroness Sugg, Transport Minister for Aviation, International and Security. 6th March 2018.

Below are three studies/articles from three highly respected professors that state otherwise. Also a proposal from John M Lind CPCU ARM, (Retired) - To Bring the Problem Of Contaminated Air Under Control - 20/01/2018.

1. Clement E. Furlong, Departments of Medicine, Division of Medical Genetics and Genome Sciences, University of Washington, Seattle, WA 98195-7760, USA;
*Email: ude.wu@melc
‘The Cranfield report (Crump et al., 2011a, b) exemplifies the futility of trying to do a prospective study of cabin air quality. It will be much more efficient and informative to follow the health of individuals known to have experienced significant fume exposures. The significance of the exposures is readily verified by the ill health of aircrew following exposures and, in many cases, these data already exist’:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3839637/

2. From Professor Chris Winder, School of Safety Science, The University of New South Wales, Sydney NSW, Australia in 2006:
https://hub.easa.europa.eu/crt/docs/viewcrdattachment/cid_40694/aid_449/fmd_3a0e0bad5d3f54f7e8b52aeaf36741a6

3. From Professor Ronald N. Kostoff:
OSHA Permissible Exposure Limits (PELs) are too Permissive.
by
Dr. Ronald N. Kostoff
Research Affiliate, School of Public Policy, Georgia Institute of Technology Gainesville, VA, 20155
Email: rkostoff@gmail.com
https://smartech.gatech.edu/bitstream/handle/1853/60067/PERMISSIBLE_EXPOSURE_LIMITS.pdf?sequence=4&isAllowed=y

John M. Lind CPCU ARM, Retired
PROPOSAL
to Bring the Problem of Contaminated Cabin Air Under Control
Executive Summary
https://aerotoxicsinanutshell.files.wordpress.com/2018/07/aerotoxic-proposal.pdf


From a House of Commons Debate Pack - For 17 March 2016:
‘The Civil Aviation Authority responded to concerns relating to cabin air safety in June 2015. It said that its priority is the safety of passengers and crew. It relies on the guidance from scientific experts based on independent studies and evidence reviews and the overall conclusions of these is that there is no positive evidence of a link between exposure to contaminated cabin air and possible health effects but such a link cannot be excluded’:

http://researchbriefings.files.parliament.uk/documents/CDP-2016-0068/CDP-2016-0068.pdf

What EVIDENCE does this government need to understand  that contaminated air is dangerous for both passengers and crew?