Carbon Monoxide CO
A precision electrochemical cell optimised for the 0–10 ppm band — the range where chronic exposure quietly accumulates, not the range where alarms scream.
Low-level exposure, tracked over time.
Most CO conversations focus on life-safety thresholds (35 ppm+). Envora monitors the band below that — the 1–5 ppm drift from a gas hob, a nearby garage or a neighbour's boiler. At these levels you will not feel symptoms, but long-term exposure is linked to headaches, fatigue and cognitive effects. Envora tracks cumulative dose, not just instantaneous peaks.
Built around Electrochemical cell (low-level).
A sealed electrochemical cell detects the micro-current produced when CO molecules react with the electrolyte. Envora runs continuous baseline compensation and exposes both live concentration and a dose-weighted 8-hour and 24-hour average — the same windows used in occupational health guidelines.
- Technology
- Electrochemical cell (low-level)
- Range
- 0–10 ppm
- Accuracy
- ~ ±2 ppm
- Resolution
- 1 ppm
- Response
- < 60 s
- Units
- ppm
Envora's electrochemical cell measures the 0–10 ppm chronic-exposure band — where slow drift quietly accumulates. For life-safety levels above that, pair Envora with a dedicated, audible CO alarm.
Natural atmosphere. Clean outdoor air.
— Background
A 1 ppm increase in maximum daily 1-hour exposure is associated with a 0.96% increase in cardiovascular hospitalisation among over-65s.
— Circulation, AHA, Sept 2009
6% increase in non-elderly asthma hospital admissions.
— Sheppard et al., Epidemiology, Jan 1999
Significant low-birth-weight risk if exposed during the last trimester (n=125,573 pregnancies).
— Ritz & Yu, Environ. Health Perspectives, 1999
EPA / WHO 8-hour outdoor max. ASHRAE indoor max. Lowest level producing cardiac effects in coronary-artery-disease patients.
— EPA · ASHRAE · Allred et al., EHP 1991
Significant increase in heart-disease deaths and congestive-heart-failure admissions.
— JAMA · Morris
WHO: impaired performance, decreased exercise capacity, vigilance decrement.
— WHO
Chronic prenatal exposure damages cells of the fetal brain, resulting in permanent impairment.
— UCLA · BMC Neuroscience, 2009
Most fire departments require firefighters to put on oxygen masks. EPA 1-hour outdoor max.
— EPA · ASHRAE
CO becomes toxic in healthy adults.
— Public health
Headache, tiredness, dizziness, nausea within 2 h. Heart and brain damage at 5 h.
— Lewey & Drabkin
NIOSH and OSHA recommend evacuation of the workplace.
— NIOSH · OSHA
Frontal headache within 1–2 hours. Life-threatening within 3 hours.
— Public health
Death in less than one hour without intervention.
— Public health
Practical steps, not panic.
- Indoor background should sit under 1 ppm. A sustained reading above that is worth investigating.
- Watch the 8-hour dose window — slow drift is the pattern Envora is built for.
- This is exposure tracking, not life safety. Pair Envora with a dedicated, audible CO alarm for the high-concentration band.
Where this channel does its best work.
Long-term toxic gas exposure
A CO alarm chirps at 35 ppm. Your nervous system reacts at 1. Envora watches the band that does not set anything off — but accumulates anyway.
Read the guideCooking pollution
Frying on a gas hob can push PM2.5 past a London roadside reading in six minutes. Most domestic extractors were never designed for it.
Read the guideCO, plus 10 more channels.
Envora One ships Carbon Monoxide alongside ten other channels, fused into one IAQ score and calibrated at our bench. £249 one-time. Free for personal households.
Free UK & EU shipping · 2-year warranty · 30-day returns · Reply within one UK business day.