baɪ ˈædɪŋ ɐ kɹˈɔːl spˈeɪs ˌʌndɚ ðə ɡɹˈaʊnd flˈoːɹ, wˌɪtʃ ɪz sˈʌbdʒɛkt tə fˈoːɹst vˌɛntɪlˈeɪʃən ðə ɹˈeɪdɑːn lˈɛvəl ɪnðə hˈaʊs kæn biː lˈoʊɚd.
By adding a crawl space under the ground floor, which is subject to forced ventilation the radon level in the house can be lowered.