This is an archived recording of the 2020 online version of the course. Continuing education credits and/or professional development hours are not available.This advanced course addresses the role of HVAC systems in helping to reduce Hospital Associated infections (HAI). What is airborne v. contact transmission? Through filtration, air patterns, air changes, dilution, temperature, humidity, UV, and pressurization the hospital HVAC can either help or hinder efforts to reduce HAI. This course describes the why and how of each of these processes from the perspective of particle physics. Instructor provides unabashed analyses of the controversies regarding the science behind the requirements in ASHRAE Std-170, such as: how many air changes, what level filtration, etc. Class will cover production and fate of airborne microorganisms and how people can get infected. HVAC design of: airborne infectious isolation rooms, protective isolation rooms, operating rooms, emergency depts, sterile processing dept, infection control risk assessment.