The Environmental Audit Committee's remit is to consider the extent to which the policies and programmes of government departments and non-departmental public bodies contribute to environmental protection and sustainable development and to audit their performance against sustainable development and environmental protection targets.

The Committee has undertaken a short inquiry to establish the adequacy of current measures to promote indoor and outdoor air quality. They will assess whether air quality targets are sufficient for protecting public health and the environment.

In response to this Inquiry, the CO Research Trust has provided its input. The interests and expertise of the Trust are in the prevention of CO exposure through the funding of research and data collection.

The objective is to build the evidence base to inform policymakers, industry, healthcare professionals and other key stakeholders.

Given this interest and expertise, the response from the Trust is restricted to comments relating to carbon monoxide, in response to the following key question:-

What are the long-term health impacts of indoor air pollution?

It is accepted that the inhalation of carbon monoxide is damaging to health, with the effect on cardiovascular (1-3), neurological (4-7) and mitochondrial function (8, 9) being well-documented.

Furthermore, pregnant women (10-11), children (12) and the unborn (13, 14) are especially vulnerable to its effects.

The threshold at which elevated carboxyhaemoglobin causes drowsiness has been placed as low as 3.4 per cent (15) with recent studies showing that lower levels have an effect on brain function (16). 3.4 per cent correlates to approximately 20ppm ambient CO (17).

Given this evidence which suggests that even low-level CO exposure may cause significant health and educational outcomes, we believe that a significant public health intervention is required.

This would fulfil Marmot Policy Objective 6: strengthening the role and impact of ill-health prevention (18), cited in the UK Government policy document, ‘Health disparities and health inequalities: applying All Our Health” (19). This also concurs with the 2019 NHS Long-Term Plan (20).


  1. Misztal T, Rusak T, Tomasiak M. Peroxynitrite may affect clot retraction in human blood through the inhibition of platelet mitochondrial energy production. Thrombosis Research (2014) 133 (3) 403-411. doi: 10.1016/j.thomres.2013.12.016
  2. Dallas ML, Yang Z, Boyle JP et al. Carbon monoxide induces cardiac arrhythmia via induction of the late Na+ current. Am J Respir Crit Care Med. (2012) Oct 1;186(7):648-56. doi: 10.1164/rccm.201204-0688OC
  3. Meyer G, André L, Tanguy S, et al. Simulated urban carbon monoxide air pollution exacerbates rat heart ischemia-reperfusion injury. Am J Physiol Heart Circ Physiol. (2010) May;298(5):H1445-53. doi: 10.1152/ajpheart.01194.2009
  4. Thom SR, Bhopale VM, Han ST, Clark JM, Hardy KR. Intravascular neutrophil activation due to carbon monoxide poisoning. Am J Respir Crit Care Med. (2006); 174:1239–48. doi: 10.1164/rccm.200604-557OC.
  5. Thom SR, Bhopale VM, Fisher D, er al. Delayed neuropathology after carbon monoxide poisoning is immune-mediated. Proc Natl Acad Sci U S A. (2004);101(37):13660-13665. doi: 10.1073/pnas.0405642101
  6. Ning K, Zhou YY, Zhang N, et al. Neurocognitive sequelae after carbon monoxide poisoning and hyperbaric oxygen therapy. Med Gas Res. (2020);10(1):30-36. doi: 10.4103/2045-9912.279981
  7. Pepe G, Castelli M, Nazerian P, Vanni S, Del Panta M, Gambassi F et al, Delayed neuropsychological sequelae after carbon monoxide poisoning: predictive risk factors in the Emergency Department. A retrospective study. Scand J Trauma Resusc Emerg Med. (2011) Mar 17;19:16. doi: 10.1186/1757-7241-19-16.
  8. Alonso JR, Cardellach F, López S, Casademont J, Miró O. Carbon monoxide specifically inhibits cytochrome c oxidase of human mitochondrial respiratory chain. Pharmacol Toxicol. (2003) Sep;93(3):142-6. doi: 10.1034/j.1600-0773.2003.930306.x.
  9. Queiroga CS, Almeida AS, Vieira HL. Carbon monoxide targeting mitochondria. Biochem Res Int. (2012); 2012:749845. doi: 10.1155/2012/749845.
  10. Grippo A, Zhang J, Chu L et al. Air pollution exposure during pregnancy and spontaneous abortion and stillbirth. Rev Environ Health (2018) Sep 25;33(3):247-264. doi: 10.1515/reveh-2017-0033. PMID: 29975668; PMCID: PMC7183911.
  11. Friedman P, Guo X, Stiller R et al. Carbon Monoxide Exposure During Pregnancy. Obstet Gynecol Surv (2015) Nov;70(11):705-12. doi: 10.1097/OGX.0000000000000238. PMID: 26584719.
  12. Macnow T, Waltzman M. Carbon Monoxide Poisoning In Children: Diagnosis And Management In The Emergency Department. Pediatr Emerg Med Pract. (2016) Sep;13(9):1-24. Epub 2016 Sep 2. PMID: 27547917.
  13. Levy R. Carbon monoxide pollution and neurodevelopment: A public health concern. Neurotoxicol Teratol. (2015) May-Jun;49:31-40. doi: 10.1016/
  14. Benagiano V, Lorusso L, Coluccia A et al. Glutamic acid decarboxylase and GABA immunoreactivities in the cerebellar cortex of adult rat after prenatal exposure to a low concentration of carbon monoxide. Neuroscience. (2005);135(3):897-905. doi: 10.1016/j.neuroscience.2005.06.058.
  15. Wright G, Randell P, Shephard R, Carbon Monoxide and Driving Skills, Archives of Environmental Health: An International Journal, (1973) 27:6, 349-354, doi: 10.1080/00039896.1973.10666400
  16. Wilson L & Herigstad M. Impact of carbon monoxide on neural activation during a reaction time task, Pre-Print, Sheffield Hallam University (2023)
  17. Fife C, Otto G, Koch S et al. A Noninvasive Method For Rapid Diagnosis Of Carbon Monoxide Poisoning. The Internet Journal of Emergency and Intensive Care Medicine (2000) Volume 5 Number 2. Available at:, accessed 20.02.23
  18. Marmot, M. Fair society, healthy lives : the Marmot Review : strategic review of health inequalities in England post-2010. (2010) ISBN 9780956487001
  19. Office for Health Improvement and Disparities. Health disparities and health inequalities – applying All Our Health. Available from:, accessed 20.02.23
  20. NHS. The NHS Long Term Plan (2019). Available from:, accessed on 20.02.23

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