Through the early twentieth century, asthmatics were advised to move to a more suitable climate, or to vacation in one during their worst season. In the late nineteenth century, physicians sought to quantify the ideal temperature, humidity, altitude, and pollen count to help travellers to select a suitable place, but these investigations led some physicians to question contradictions between expected and actual conditions. Given that even the best climate was not perfect at all times, and that many patients could not (...) afford to travel or relocate, a group of physicians—who came to be known as allergists—sought ways to adapt their patients to any climate through changes in their indoor environments and treatments to manage their symptoms. Their approach included changes in household design, furnishings, and cleaning techniques, especially a strict avoidance of dust, which could carry feathers, animal hair, skin debris, pollen, moulds, and an unknown ‘dust’ allergen. Air filtering and air conditioning were also promoted as ways to protect asthmatics and hay fever sufferers. These modifications of patients and their microenvironments signalled both a move away from climactic approaches to asthma and toward the sanitary, modernist home of the twentieth century. (shrink)