radon

There has been substantial concern about the potential for radon levels to increase in homes undergoing energy retrofits, especially those including substantial air sealing. This study evaluated if precautionary measures could curb increases in radon in over 250 homes receiving energy efficiency retrofits. The goal of these precautionary measures was not to provide full radon mitigation, but rather to avoid increases in radon following retrofit.

Radon is a naturally occurring gas that is hazardous to human health, making it desirable to minimize exposure. Radon can infiltrate buildings and accumulate to concerning levels, especially in those with tight exterior envelopes and low fresh air exchange rates. Previous research has suggested that air sealing, a common tool for improving building energy efficiency, can increase indoor radon concentrations (Pigg et al. 2017).

Radon is one of the common contaminants inside buildings, with maximum presence in high potential areas classified as radon prone areas. This radioactive gas, which comes from the spontaneous disintegration of radium present in the earth's crust, can penetrate buildings and accumulate inside them. The spaces closest to the ground (basement and first floors) are the most affected. Its inhalation in high doses is associated with an increased risk of lung cancer. Several techniques are commonly used to mitigate its presence.

Purpose of the work

To expand the use of BlowerDoor and thermal equipment combined with Radon

Method of approach

When building is set on very low negative pressure, use the Radon sniff-equipment called RAD7 to count radon at places where thermal imaging camera tell there is draft that can be assumed tob e leaks from the ground. If the found leakages are from the ground it often show higher level of Thoron, Radon and Polonium values, than the measurements elsewhere in the room.

Conclusions

Health Canada’s cross-Canada residential radon survey report from 2012 demonstrated that roughly 7% of Canadian homes contain radon levels above the Canadian guideline of 200 Bq/m3. The research outlined in this paper evaluates the effect of ventilation rates on radon levels in two homes located in Ontario, Canada. The first case study consisted of short-term (2 day) radon monitoring in a home using three ventilation strategies; one heat recovery ventilator (HRV) running, two HRVs running, and both HRVs turned off.

Radon gas is a well-known building´s pollutant which can affect negatively people´s health (WHO, 2009). Radon´s source is the soil underneath buildings. Radon moves from the soil to the buildings by advection through cracks and joints, and diffusion through porous materials. Once radon enters buildings it can accumulate in lower areas due to lack of ventilation. Ventilation is one of the main ways to prevent radon from accumulating in enclosed spaces in the case of moderate radon concentrations up to 600 Bq/m3 (Collignan, 2008). 

A methodology was developed to calculate health damages due to exposure to radon emitted to indoor air for use in dwelling life cycle assessment. Fate factors were calculated based on dose conversion factors and effective outgoing airflows. Effect factors were calculated from linear relationship between dose and cancer cases. Damage factors are expressed in terms of disability adjusted life years (DALYs).

Performance of radon mitigation systems, including active sub-slab ventilation, basement over-pressurization and crawlspace isolation and ventilation, was monitored in 12 houses in the USA during 10 years. Results are given showing the radon concentrations measured quarterly or annually. Results of the inspection of the mitigation systems and the needed maintenance and modifications of the systems to maintain and improve their performance are also reported.

Considering the likelihood of contributions of various indoor air pollutants to detrimental health effects, the Community-COST Concertation Committee of the Concerted Action "Indoor Air Quality and its lmpact on Man" (COST Project 61 3) decided that indoor radon is a well studied indoor pollutant both in terms of occurring concentrations and expected adverse health effects. In July 1985 the Article 31 Euratom Treaty Group of Experts set up a Working Party to study and report on this matter.

Radon concentration in outdoor air and in buildings is very variable, showing diurnal and seasonalvariations. Long term measurements with track etch detectors lasting up to one year give the mostprecise one year averages. It arrives, however, that we are obliged to get results much sooner e.g. forscreening measurements. How long should we measure radon concentration to get proper results? Wehave studied the problem of selecting proper time interval on the basis of our six long-termmeasurements in Krakw using AlphaGUARD PQ-2000 ionization chamber.