Plan tool use with quick, practical CO checks. Compare ventilation, distance, and run time easily. Protect your family, plants, and lungs every session outdoors.
| Mode | CO ppm | Minutes | Space | Dose (ppm·min) | Risk level |
|---|---|---|---|---|---|
| Meter | 15 | 30 | Open outdoors | 450 | Low |
| Meter | 50 | 45 | Covered patio | 2250 | Elevated |
| Estimate | 240 (estimated) | 20 | Shed / garage | 4800 | Elevated |
| Estimate | 700 (estimated) | 20 | Greenhouse | 14000 | Severe |
Carbon monoxide can accumulate in sheds, greenhouses, and garages where heaters, generators, grills, or small engines run. Poor ventilation, blocked flues, and tight weather‑sealing increase exposure, especially in winter. Because CO is colorless and odorless, symptoms may be mistaken for fatigue or dehydration. Use this calculator to translate activity, space, and ventilation into a practical risk estimate.
Risk depends on the dose you breathe. Dose rises when concentration is higher, exposure lasts longer, and fresh air exchange is low. This tool models dose as a concentration‑time product (ppm·min) and then adjusts it using airflow, room volume, and physical exertion. That helps compare scenarios, such as a brief start‑up outside versus a long session in a closed potting shed. When available, enter readings from a calibrated monitor; avoid guessing values from odor or smoke alone.
Treat the risk category as a prompt for action, not a guarantee. If you see High or Severe, stop the source, move to fresh air, and reassess before returning. Consider scheduling engine work outdoors, using extension cords for electric tools, and opening high and low vents to promote cross‑flow. Record your inputs to build a site‑specific checklist for recurring tasks.
Engineering controls come first: vented heaters, maintained chimneys, and dedicated exhaust paths. Administrative controls include limiting run time, keeping doors open during start‑up, and avoiding idling equipment near intakes. Personal controls include recognizing early symptoms, working with a partner, and taking breaks. A properly placed CO alarm adds an extra layer of warning, especially in enclosed workspaces. Pair alarms with equipment maintenance, because soot, rust, and back‑drafting can spike emissions.
This calculator provides an estimate based on typical response patterns and simplified airflow assumptions. Altitude, temperature inversions, health conditions, and competing pollutants can change real‑world outcomes. If anyone feels headache, dizziness, nausea, confusion, or unusual sleepiness, leave the area and seek medical advice promptly. Call emergency services if severe symptoms or unconsciousness occurs. Use professional monitoring for repeated work in enclosed structures or when regulations apply.
The category summarizes estimated CO dose after ventilation and activity adjustments. It helps compare scenarios and prioritize controls. It does not guarantee symptoms or safety under every condition.
Use readings from a CO monitor when possible. If you only know the source type, start with conservative assumptions and improve ventilation. Avoid estimating from smell, because CO has no odor.
Enter the best estimate of fresh air flow into the space. Open doors, vents, and fans increase airflow. If unknown, use a low value to see worst‑case results and then test improvements.
Yes. Higher exertion increases breathing rate, which raises inhaled dose at the same concentration. Select the activity level that matches your task, especially during digging, hauling, or engine handling.
No. A CO alarm or monitor provides real‑time warning and can detect unexpected spikes. Use the calculator for planning and recordkeeping, then verify your workspace with proper detection equipment.
Stop the combustion source, move everyone to fresh air, and ventilate the area. Do not re‑enter until levels are controlled. Seek medical help if symptoms occur, and call emergency services for severe signs.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.