You purchase a house with a known radon problem. The house has a 1 m high dirt-floored crawl space. The emission rate of radon into the crawl space is reported to be 0.6 pCi/m2s. An exhaust system was added to provide 1 air exchange per hour (ACH) in the crawl space. The outdoor concentration of radon is 1 pCi/L.
Develop a mass balance for this problem and estimate the steady-state radon concentration in the crawl space (in pCi/L).