Toxicity of Carbon Dioxide: A Review

Abstract

The toxicity of carbon dioxide has been established for close to a century. A number of animal experiments have explored both acute and long-term toxicity with respect to the lungs, the cardiovascular system, and the bladder, showing inflammatory and possible carcinogenic effects. Carbon dioxide also induces multiple fetal malformations and probably reduces fertility in animals. The aim of the review is to recapitulate the physiological and metabolic mechanisms resulting from CO(2) inhalation. As smokers are exposed to a high level of carbon dioxide (13%) that is about 350 times the level in normal air, we propose the hypothesis that carbon dioxide plays a major role in the long term toxicity of tobacco smoke.

Environmental CO 2 inhibits Caenorhabditis elegans egg-laying by modulating olfactory neurons and evokes widespread changes in neural activity

“…As an alternative paradigm, we examined whether CO 2 altered egg-laying behavior. We hypothesized that mechanisms should have evolved to prevent worms from exposing their offspring to adverse concentrations of CO 2 (25,51). To test this idea, we placed individual worms on thin bacterial lawns, exposed them to either 5% or atmospheric CO 2 concentrations, and compared the number of eggs laid by each group after 2 h. Strikingly, N2 animals essentially stopped laying eggs at 5% CO 2 , implying that CO 2 has an immediate and long-lasting inhibitory effect on egg-laying ( Fig.…”

Nondrowning Asphyxia in Veterinary Forensic Pathology

“…17 Only after the larynx was also manually compressed was asphyxia produced, resulting in an isoelectric electroencephalogram (EEG) at 40 seconds to 2 minutes, apnea at 4 minutes, and cardiac arrest at 9 to 10 minutes. 17 Many of the experiments in dogs, cats, rabbits, and rats simulating ligature and manual strangulation and hanging 12,50,55,56,62,[66][67][68] are reviewed by Boghossian. 13 Based on these papers, the general sequence of physiological responses is respiratory distress and tachycardia, followed by bradycardia, then apnea, an isoelectric (EEG), terminal or agonal respirations, and cardiac arrest.…”

“…Mechanisms of CO 2 toxicity are reviewed by Guais et al 56 Elevated atmospheric CO 2 is encountered in industrial settings, from use of dry ice, and with combustion, fermentation, or putrefaction. 56 Probably most animals exposed to toxic levels of atmospheric CO 2 are those intentionally euthanized by this method, although fatal hypercarbia in dogs and cats is reported due to malfunction of an anesthetic machine. 21 Strongly aversive responses occur in animals exposed to even very high concentrations of CO 2 until unconsciousness is reached.…”

Perception of Cabin Air Quality among Drivers and Passengers

“…For example, at a concentration higher than 5% (50,000 ppm), effects such as the increase of blood pressure and heart rate [31], the occurrence of extra systoles during effort [32] or the increase of blood supply to the kidneys and brain have been identified [33]. Also, at levels higher than 50,000 ppm, the effects on the central nervous system were highlighted, such as headache symptoms, dizziness and physical arousal [34], and even visual disturbances [32] at concentrations above 100,000 ppm.…”

“…There are also a few studies which do not always highlight the significant effects of CO 2 's influence on cognitive skills [31].…”