A more common application is in the Mond process, in which carbon monoxide is used in a three-stage process to purify nickel. So carbon monoxide has turned out to be more than just the bogeyman of our smoky industrial age. But it is for its fatal attraction to our blood that it remains most well known, and in the last decade even this harmful property has found a use. For just as carboxyhaemoglobin is so vivid, so myoglobin, a related protein found in blood, turns a fresh-seeming pink on exposure to carbon monoxide.
Thus, food scientists have turned to carbon monoxide to impart an appealing colour to cuts of meat. Although banned in many countries including much of Europe, given the history of carbon monoxide, this seems a somewhat macabre application of the little compound's big problem. The lengths taken to make our food look more appealing. Now, next week: all eyes on the poppy for some pain relief. If you cut open the seed pods of the common poppy before they ripen, they exude a creamy coloured sap which contains a mixture of perhaps 50 different alkaloids - molecules made by the plant from amino acids.
The sap dries to a yellow-brown paste. This is opium. And one of the most abundant compounds present in opium is morphine, the substance that sets the standard by which all painkillers are judged. And to discover the chemistry enabling these pain-relieving effects of morphine on our bodies, join Simon Cotton in next week's Chemistry in it's element. Until then, thank you for listening. I'm Meera Senthilingam. A DNA researcher tells the story of how humans have shaped the evolution of living things on Earth.
Site powered by Webvision Cloud. Skip to main content Skip to navigation. Related audio. Book club — Deep Sniff by Adam Zmith. Book club — Lessons from Plants by Beronda Montgomery. Carbon monoxide. Duncan McMillan uncovers the chemistry behind this deadly compound. Meera Senthilingam This week, a deadly compund with a rosy glow that's also dreaded by many a canary. As Sam Leith described in a review of his biography: ' He gassed himself with chlorine, methane, carbon dioxide, carbon monoxide, pure oxygen, nitrogen, mustard gas and god knows what else in various combinations Topics canary bird carbon monoxide Chemistry in its Element: Compounds CO coal mining gas Podcasts poisonous gas toxic.
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To link your comment to your profile, sign in now. Only registered users can comment on this article. Sign in Register. Common aspects of mental deterioration include persistent headaches. It is not possible to predict who will develop delayed effects. Although problems may develop in patients who have had only mild to moderate toxic levels in their systems, there is a tendency for it to occur with greaterfrequency in thosepatients who have had prolonged episodes of unconsciousness.
These persistent effects of CO are not generally appreciated and present a significant personal and financial dilemma for those affected. Who Is At Risk? Children are at greater risk to experience nervous system symptoms at lower levels due to their inherently higher metabolism.
Adults with preexisting heart disease may develop associated problems, such as angina, at significantly lower levels than healthy adults, placing them at greater risk for a heart attack. Smoke inhalation victims may become comatose at seemingly mild toxic levels of carbon monoxide, due to the inhalation of other toxic by-products of combustion such as cyanide that produces similar cellular suffocation.
Pregnant females who are exposed to CO pose a significant risk to the fetus as the recovery half-life is significantly increased due to fetal to maternal blood transport complications. Since the underlying process of CO poisoning is the accumulation of CO and the suffocation of the cells, the main treatment steps include removing the victim from further exposure to CO and the use of oxygen.
The use of high concentrations of oxygen will enhance the elimination of the CO from the blood and provide oxygen to the tissues that have become oxygen-starved. In more serious CO poisoning cases, hyperbaric higher than atmospheric pressures oxygen is administered to the patient as a way to dissolve large amounts of oxygen in the blood, which reverses the suffocation and enhances more rapid elimination of the CO. CO Alarm Technology.
However, electrochemical and non-dispersive infrared sensor technologies are available in a few consumer models. Biomimetic sensors rely upon the selective transport of CO into a chemical tablet which then darkens in proportion to the amount of CO received.
The unique feature of this patented technology is that the sensor can be designed to release half of the CO absorbed in three to four hours, allowing it to mimic the human response to CO see above. Semiconductor sensors employ heated beads which are chemically-doped to selectively burn CO on their conductive surfaces.
Electrochemical sensors used in consumer style CO alarms bear traits common to the electrochemical sensors used in field meters. However, parts per million precision is not required since the sensor is being used for consumer alarms. Non-dispersive infrared sensors rely upon the selective absorption of specific wavelengths of light by the CO molecule.
This light absorption may be readily correlated with a specific concentration of CO gas. This absorption wavelength is chosen to be distinct from other compounds that may be present, thus providing selectivity of the sensor. Flame color is not an accurate measure of CO concentrations. What is normally accepted as a safe blue flame may still be producing excessive concentrations of carbon monoxide. Measurement of CO in the flue gases is the only reliable method to determine if complete combustion is occurring.
For many years the best available method for measuring CO in the field was stain-length tubes. This affordable method has limitations in accuracy, interpretation of reading and heat interference.
All these limitations have been overcome with the application of electrochemical CO sensors in field meters. Electrochemical sensors generate an electrical current proportional to the CO molecules that interact with a chemical solution that is behind a permeable membrane. Some sensors employ sophisticated constructions and filters allowing for the specific determination of CO concentration, even when directly measured in the flue gas.
Flue gas measurement capability is the preferred method of measurement. Response To CO Alarms. A large number of homeowners report their carbon monoxide detectors are alarming.
The causes for many detector alarms remain unresolved. There is no agreement on:. Reliability of detectors, Competency of investigators, Number of persons exposed to carbon monoxide at low or high concentrations, Sources and reasons for exposure to carbon monoxide, Acceptable or expected concentrations of carbon monoxide, Risks of exposure to low concentrations of carbon monoxide, Medical treatment.
Design criteria for heating appliances. There are wide differences of opinion concerning carbon monoxide detector risks and carbon monoxide detectors. In part. The U. Individuals and groups responding to detector alarms report widely differing results. It appears the prevalence of carbon monoxide is much larger than previously estimated. The number of reported CO exposuresis likely to increase as more detectors are installed, and the number of CO sources identified is likely to increase as professionals become better trained and equipped.
Nationwide uniform data on the number of emergency carbon monoxide calls or the results of those calls do not exist. In many communities, the fire departments respond to emergency I calls. Fire department data report forms do not include a separate category for carbon monoxide, making it difficult to collect data.
A survey of fire departments is now taking place in Iowa. Analysis of data from the Pittsburgh CO response efforts is presently underway. Preliminary indications are that fire departments and utility companies are responding to thousands of requests, with varying results. A survey of Iowa heating contractors indicate they are responding to hundreds of carbon monoxide-related calls.
Some contractors report they found carbon monoxide in all cases after a CO detector alarmed. Others report never finding CO after an alarm.
The disparity raises serious questions. Iowa indoor air quality studies in 65 Iowa homes found 29 homes with excessive concentrations of carbon monoxide produced by the furnace or water heater.
The individual has little direct or immediate control over the outdoor exposure in the macroenvironment, such as exposure from power plants during air inversions. Other outdoor exposures at the micro-environment level can be modified. For instance, a jogger can avoid jogging next to busy streets and people can use electric lawn mowers rather than gas. Carbon monoxide problems can be caused by: engines run in attached garages; unvented appliances; problems with heating system design, poor installation, improper modifications, poor condition, poor maintenance; inadequate combustion air; house depressurization; and blocked or failed chimneys.
The amount of indoor carbon monoxide resulting from carbon monoxide entering the home can be difficult and expensive to reduce.
Outdoor CO can be a significant reason for elevated indoor levels. Indoor carbon monoxidefrom sources such as from engines cars run in attached garages can be reduced by opening the outside door and limiting the time the engine is run before the engine car is removed from the garage. Carbon monoxide exposure from gas kitchen stoves can be reduced by propermaintenance and operation of a vented range hood. Exposure to CO caused by intermittent spillage from vented appliances is often difficult to detect, but has serious consequences.
Accidental exposures can be sporadic and widely isolated. Small-scale short-term monitoring of ambient carbon monoxide concentrations in homes is unlikely to discover these exposures. While the distribution of concentrations was well defined, it is not possible to project the proportion of homes that have hazardous conditions leading to life- threatening concentrations of carbon monoxide.
A large-scale residential survey with considerably more homes would be necessary to identify enough homes with high CO concentrations in order to uncover patterns and common causes of the high concentration outliers. By continuously monitoring for CO, residential carbon monoxide detectors are one means of preventing CO accidents. Utility companies report thousands of alarms sound each year. Minnegasco a Minnesota natural gas utility responded to 13, carbon monoxide calls in one year.
Data from field investigations initiated because of residential detector alarms raises the following questions: how many CO detectors are in place, how many CO detectors alarmed, are residential detectors reliable, what were the CO concentrations causing the alarm, what was the extent of the exposure, was medical treatment sought, was adequate medical diagnosis performed, what was the source of CO, were the investigators trained and equipped to discover CO sources, how adequate was the investigation, and how many times do investigators fail to find a source that was present?
Accidental carbon monoxide exposure in a home can be difficult to reproduce and document. A team performed follow-up CO investigations in 50 Minnesota homes. The occupants of these homes called Minnegasco Utilitytwo or more times for carbon monoxide checks. Negligible concentrations were found. The follow-up investigations found sources of carbon monoxide in 49 out of 50 cases. The home with no sourcefound did not have a CO detector. Vented appliances and appliances that exhaust air must have adequate combustion and make-up air.
Everything that changes air flow can adversely affect the safe operation of heating appliances including: weather; house orientation, shape and size; exterior obstructions; vent location, height, size, and type; bathroom exhaust fans; vented kitchen range hoods; clothes dryers; size, shape, and location of air leaks; attic ventilation; vented gas appliances; wood-burning fireplaces; operation of furnace blower; and furnace return and supply ducts location and leakage.
The interactions of these factors combine in complex ways to cause vent failure in natural draft appliances that depend on extremely small pressure differences to draft correctly. For example, in some cases simply adding an exhaust fan or recessed ceiling lights, sealing basement windows, or closing a supply register can upset the balance, causing combustion products to spill into the home. It appears that in many instances no one is taking responsibility for ensuring a house functions correctly, either during design, construction, maintenance, or modifications.
There are few organizations or individuals with the training or equipment to either design or troubleshoot such systems. In many U. Preventative Measures — Short Term. The following actions reduce consumer risks of CO poisoning in their home:. Installation of detectors meeting UL requirements;. Yearly service of heating appliances by a qualified service technician;. Immediate action to protect all building occupants when a detector alarms.
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