The Efficacy of the Dyson Air Purifier in Improving Asthma Control: Protocol for a Single-Center, Investigator-Led, Randomized, Double-Blind, Placebo-Controlled Trial oleh Wei Chern Gavin Fong, Susan Grevatt, Stephen Potter, Tracey Tidbury, Latha Kadalayil, Kaisha Bennett, Maria Larsson, Frédéric Nicolas, Ramesh Kurukulaaratchy, Syed Hasan Arshad