School Inner City Air Study

The goal of this randomized clinical trial is to test the efficacy of high efficiency particulate air (HEPA) cleaners in reducing respiratory viral exposure and infections in elementary school classrooms. Classrooms will be randomized to active vs. sham HEPA cleaners. The main questions it aims to answer are: * Do classroom HEPA cleaners reduce exposure to viruses? * Do classroom HEPA cleaners reduce student and teacher infections? * Do classroom HEPA cleaners reduce infections in family members?

Classrooms from participating schools will be randomized to active vs. sham HEPA cleaners. From enrolled classrooms, we will enroll students, teachers, and members of the household. We will collect the following: * longitudinal classroom air samples * longitudinal upper respiratory samples * longitudinal symptom surveys using the Wisconsin Upper Respiratory Symptom Survey (WURSS) Viral testing on collected air and respiratory samples will be performed using digital polymerase chain reaction (dPCR).