Heating season brings news of carbon monoxide accidents. The NHS says carbon monoxide has no smell or colour, so you can’t detect it yourself. Symptoms include headache, dizziness, feeling or being sick, weakness, confusion and shortness of breath, and they often get worse in the affected room or building and ease when you leave or go outside. If you suspect it, stop using the appliance and go outside, and don’t go back in until you’ve had medical advice. To prevent it, fit a carbon monoxide alarm in each room with a gas, oil, coal or wood appliance. This sets out the NHS page “Carbon monoxide poisoning”.
1. No smell, no colour — suspect it when headache, dizziness or nausea are worse in one room and better outside.
2. Switch off the appliance, go outside, don’t go back until advised. Don’t drive yourself to A&E.
3. An alarm in every room with a fuel-burning appliance, regular servicing, ventilation, no barbecues or camping stoves indoors.
Symptoms and how to spot it — NHS
- Headache, dizziness, feeling or being sick
- Weakness, tiredness, confusion
- Chest and muscle pain
- Shortness of breath
- Flushing, where the face turns hot and red (harder to see on brown and black skin)
- Loss of vision
The NHS says symptoms may come and go, and often get worse in an affected room or building and ease after you leave or go outside. Since you can’t smell it, symptoms that change with the place are the clue (our reading).
General NHS headache advice is in headaches, and dizziness in dizziness. If either is only bad at home, read this page too.
What to do straight away — NHS
| Step | What the NHS says | Worth noting (our gloss) |
|---|---|---|
| 1 | If you can, stop using the appliance you suspect — boiler, cooker, heater | — |
| 2 | Go outside | — |
| 3 | Get medical advice as soon as possible; don’t go back in until advised | — |
| 4 | Don’t drive yourself to A&E — ask someone or call 999 | No reason given on the page |
The NHS splits it: 111 if you think you might have symptoms; 999 or A&E if you think you or someone else has been exposed and has difficulty breathing, sudden confusion, loss of consciousness, weakness, or chest or muscle pain.
Where it comes from — NHS
- Appliances that are not installed correctly, faulty or poorly maintained — gas boilers, gas cookers and clay ovens, gas or paraffin heaters, wood, gas and coal fires, portable generators
- Using barbecues or camping stoves indoors
- Running vehicle or lawn mower engines in enclosed spaces such as garages
Prevention — NHS
| What | What the NHS says | Worth noting (our gloss) |
|---|---|---|
| Alarms | A loud alarm in each room with a gas, oil, coal or wood appliance | Korean rules in the alarm post |
| Servicing | Install properly and service regularly by a qualified, registered engineer | No interval given here |
| Ventilation | Keep rooms well ventilated; keep chimneys and flues clean | — |
| Avoid | Barbecues or camping stoves indoors or in a tent; engines running in enclosed spaces | Relevant to winter camping |
| Avoid | Oversized pots that cover more than one gas ring | — |
The NHS page also gives a UK gas helpline, which we haven’t copied as it doesn’t apply to Korean readers. Whether CO alarms are compulsory in Korea is covered, with the notice text, in carbon monoxide alarm rules.
Checklist
- ☐ Headache, dizziness or nausea that’s worse only at home
- ☐ If suspected: appliance off, go outside, don’t go back in
- ☐ Difficulty breathing, confusion or collapse: emergency help
- ☐ An alarm in each room with a fuel-burning appliance
- ☐ No camping stoves or barbecues in tents or indoors
Questions that remain
If I can’t smell gas, am I safe?
No. The NHS says carbon monoxide has no smell or colour. You can’t detect it by smell.
How often should a boiler be serviced?
The page only says “regularly” and gives no interval.
Sources
- NHS — Carbon monoxide poisoning — source (page shows: reviewed 16 December 2025, next review 16 December 2028; checked 13 October 2026). Symptoms, place-dependent pattern, immediate steps, 111 and 999, causes, prevention.
- Not read. Korean agency first-aid guidance on carbon monoxide poisoning.
- Not copied. The UK gas helpline.
- What we added. The “worth noting” column.
Where else to check
- Your gas supplier or a boiler engineer — appliance checks.
- The nearest emergency department — if you have symptoms.
Written on 13 October 2026. The content is from the NHS; the glosses are ours. It does not replace diagnosis or treatment.
