بُخَارِهِ literally evokes “its vapor.” The image emphasizes possible indirect contact with an environment permeated by usury. The printed expression is kept as written rather than replaced by another wording.
The warning does not establish that every transaction of every person is automatically usurious or prohibited. Specific contracts require examining their actual terms and nature.
Example: Before agreeing to a loan or commercial arrangement, learn the relevant difference between unlawful interest and a permissible price or profit through reliable guidance.