Matt Myers attended our workshop in September, and he used it straight through December. On December 7th, he sent me a picture of the blackest HEPA (and pre-filter) I’ve ever seen. Yikes!
Time for a new filter! I’d be happy that black gunk is in the filter and not in my lungs.
芝加哥大学行为科学系的助理教授; Smart Air创始书呆子。