Carbon monoxide is a colourless, odourless gas produced when carbon-containing fuels burn incompletely. In buildings, it can arise from cooking, water heating, standby power generation, charcoal use and the movement of exhaust from adjoining areas.
Gas cooking appliances can generate carbon monoxide where combustion is incomplete, flames are poorly adjusted, burners are dirty or the appliance is used without adequate ventilation. Water heaters and other fuel-burning appliances can also release carbon monoxide if combustion products spill into the room or if the flue arrangement does not remove them effectively.
Standby generators are another important source. Exhaust can enter through doors, windows, service penetrations or ventilation intakes when a generator operates near an occupied building. The risk is influenced by the position of the exhaust, wind movement, pressure differences and the location of fresh-air intakes.
Charcoal and shisha use can produce substantial combustion gases because glowing charcoal continues to release carbon monoxide even when little smoke is visible. The absence of dense smoke should not be treated as evidence that combustion gases are absent. Enclosed or partly enclosed use can allow carbon monoxide to build up where air replacement is insufficient.
Carbon monoxide may also migrate from adjacent car parks, loading bays and commercial kitchens. Vehicle exhaust can pass through doors, ramps, lift lobbies, service shafts or ventilation systems, while kitchen combustion products can enter neighbouring areas through pressure imbalances or poorly located air intakes.
Total volatile organic compounds, or TVOC, is a combined measure of selected organic chemicals detected through a defined analytical approach. Carbon monoxide is not an organic vapour and is not included within a TVOC sum. A low TVOC result therefore provides no information about whether carbon monoxide is present.
The two measurements also answer different questions. TVOC is often used as a broad indicator of the combined burden from solvents, fragrances, materials and other organic sources. Carbon monoxide measurement is directed at combustion, exhaust ingress and the adequacy of fuel-burning equipment or separation from vehicle areas.
Carbon monoxide can change quickly as an appliance, generator or vehicle source starts and stops. Continuous or time-resolved monitoring may therefore be more informative than a single isolated reading where intermittent combustion is suspected. The sampling plan should reflect the source schedule, occupancy pattern and likely route into the room.
Because carbon monoxide has no reliable warning odour, subjective assessment cannot substitute for measurement. Headache, dizziness, nausea and weakness can occur with exposure, but these symptoms are not specific to carbon monoxide. A symptomatic person should seek prompt medical assessment rather than attempting to diagnose the cause from building conditions alone.
For existing buildings, Table 2 of Dubai Municipality's Technical Guidelines for Indoor Air Quality for Healthy Life gives carbon monoxide values of 9 ppm, equal to 10 milligrams per cubic metre, over 8 hours and 90 ppm, equal to 100 milligrams per cubic metre, over 15 minutes. The guideline also prints a one-hour row whose stated parts-per-million and milligram-per-cubic-metre figures do not convert to one another, so it is not reproduced here. It also gives a ceiling of 200 ppm.
Table 2 is expressed in mandatory terms within Dubai Municipality's technical guideline. The guideline is not statutory law, and the existing-building route is not voluntary. The status should be stated beside the figures so that they are not presented as a universal federal legal limit or confused with the optional certification route for new buildings.
The averaging period is part of each value. An 8-hour result cannot be compared directly with a short reading without considering how the source varies over time. A brief peak from a generator or vehicle queue may be highly relevant even where a longer average is lower.
A report should identify which Table 2 metric is being applied, how the instrument recorded the concentration and whether the monitoring period captured normal source operation. Without that context, a numerical comparison can appear more definitive than the evidence allows.
The WHO Guidelines for Indoor Air Quality: Selected Pollutants, published in 2010, state that the guidelines have the character of recommendations. For carbon monoxide, WHO gives 100 milligrams per cubic metre over 15 minutes, 35 milligrams per cubic metre over 1 hour, 10 milligrams per cubic metre over 8 hours and 7 milligrams per cubic metre over 24 hours.
These WHO values are recognised international health-based guidance, not UAE law. They can provide an additional interpretive reference, particularly where the duration of concern extends beyond the periods addressed in a local instrument. Their status should remain explicit whenever they are cited.
Al Sa'fat section 401.07 applies to listed categories of existing buildings and states that the buildings must apply the specified procedures. It gives carbon monoxide below 9 ppm as an 8-hour time-weighted average. Al Sa'fat is a building-code and rating instrument rather than occupational-health law, and its figure belongs to that specific existing-building provision.
Dubai Municipality Table 2, WHO guidance and Al Sa'fat should not be merged into a single generic limit. They differ in legal character, scope, averaging structure and purpose. Accurate reporting names the source of each figure and avoids implying that all three instruments regulate every UAE building in the same way.
Dubai Municipality clause 9-5 addresses enclosed parking. It requires carbon monoxide to be held below 50 ppm as a ventilation control threshold rather than a time-weighted average, a minimum of 6 outside air changes per hour and a minimum of 1 carbon monoxide sensor per 400 square metres. It also requires occupied areas connected to enclosed parking to be supplied with conditioned air under positive pressure.
These provisions recognise that control depends on more than a concentration reading. Ventilation removes vehicle exhaust, sensors provide information for operation or control, and positive pressure helps resist movement from the parking area into connected occupied spaces.
A parking sensor network is not automatically representative of every neighbouring room. Exhaust may enter through a local doorway, lift shaft or intake even when a remote parking sensor has not detected the same concentration. Investigation should therefore consider pressure relationships, door use, vehicle activity and the physical route between the source and the affected space.
The clause 9-5 value should not be substituted for the Table 2 occupied-space values. The parking provision addresses an enclosed vehicle area and its ventilation arrangements, while Table 2 addresses indoor-air objectives for existing buildings under the technical guideline.
A carbon monoxide alarm is designed to provide a warning when its internal response criteria are met. It is a life-safety device, not a general-purpose survey instrument. Its indication depends on sensor design, placement, condition and the way its response logic treats concentration and time.
A measurement exercise has a different purpose. It may record changing concentrations, investigate a suspected source, compare connected areas or assess an averaging period from a guideline. The instrument may provide data at shorter intervals and may be positioned according to the suspected exposure route rather than the fixed location of an alarm.
The absence of an alarm signal does not demonstrate that every relevant guideline value has been met. An alarm may be functioning correctly while remaining silent at concentrations or durations that still matter to an investigation. Conversely, a survey instrument does not replace the need for appropriate life-safety alarms where they are required by the building's fire and safety arrangements.
Both functions should therefore be preserved. Alarms provide ongoing warning capability, while measurement supports diagnosis, source control and documented comparison. Calibration, sensor condition and placement are important in each case.
Nitrogen dioxide is another important indoor combustion by-product, particularly where gas flames or other high-temperature combustion sources operate. Unlike carbon monoxide, it has its own chemical behaviour and respiratory effects, so it requires separate measurement rather than being inferred from a carbon monoxide result.
The WHO 2010 guidelines give nitrogen dioxide values of 200 micrograms per cubic metre over 1 hour and 40 micrograms per cubic metre as an annual average. These values have the character of recommendations and are not UAE statutory limits.
Carbon monoxide and nitrogen dioxide do not necessarily rise in the same proportion. Burner condition, flame temperature, fuel, appliance design and ventilation can alter their relative production. Measuring one gas cannot reliably establish the concentration of the other.
Flue-gas and combustion analysis on chimneys and boilers is a separate environmental monitoring discipline covered elsewhere.
A carbon monoxide result indoors is read against the Dubai Municipality guideline figure, while combustion plant and enclosed parking are separately governed by ventilation provisions drafted in quite different terms; how those instruments relate is set out in Regulation of indoor chemical contaminants in the UAE.
Dubai Municipality DM-HSD-GU119-IAQ Version 4 (11 December 2024) — clause 9-8-3 figures apply to a voluntary certificate route; clause 9-8-4 is worded as mandatory within the guideline
No. Carbon monoxide is not included in TVOC. A normal TVOC result does not assess combustion gases, vehicle exhaust or generator emissions.
No. An alarm provides a life-safety warning according to its own response design. A measurement exercise records concentrations for source investigation, time averaging and comparison with the selected guidance or technical instrument.
Vehicle exhaust can move through doors, lift lobbies, ramps, shafts and pressure pathways. Positive pressure in connected occupied areas and effective parking ventilation help reduce that movement, but local routes still need to be examined where ingress is suspected.
Not in every investigation, but it should be considered where gas cooking, water heating or other combustion sources could produce both gases. A carbon monoxide result cannot be used to calculate or assume the nitrogen dioxide concentration.
Fuel-burning equipment should not be treated as safe merely because no odour is present. Symptomatic people should move away from the suspected source and seek prompt medical assessment, while the building condition is examined by an appropriately competent person.