Opening windows and radon the number falls, then the house closes
Opening the windows mixes indoor air with outdoor air, where radon is diluted. The number falls. As soon as the house closes for the heating season, soil gas starts to build up again. Nobody leaves the windows open at −20 °C for three months. The annual average includes those three months.
Airing the house is still a reasonable step for an hour of work, or for a test you are trying to understand. It is not the fix Health Canada describes. The fix pulls under the slab and exhausts outside, with the house closed. The system. Closed house.
Reference points: Health Canada, what you need to know about radon and the 200 Bq/m³ guideline. The two-year timeline between 200 and 600, and one year above 600, comes from Health Canada’s guide for radon measurements in homes.
The 4-day test gives a first reading. The 91-day test covers the three-month minimum Health Canada asks for. Both are $59 before tax: shipping, return and the laboratory are included, taxes extra. The PDF report is sent within 2 business days after the laboratory receives the detector.
Above 200 Bq/m³, mitigation is confirmed with a quote. Gaz Radon is C-NRPP certified for measurement and mitigation.
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