17 MAY, 2020 - AIR ... conditioning/heat/exchange
Although you read about it here ...over a month ago... the Scientists and Doctors (I cringe at giving them that title), at the CDC have FINALLY re-discovered that COVID19 -and other Viruses-and Bacteria-and Fungi are being spread by AIR CONDITIONER AND BLOWER SYSTEMS FOR HEAT, COOLING AND RECIRC, just like we used to see in those 1960's-1970's ASHRAE publications, (OR EVEN THIS ONE FROM BACK IN 2009) https://www.hpac.com/iaq-ventilation/article/20930001/strategies-for-reducing-microbial-contamination-in-hvac-systems
This is late 1800's kowledge level stuff.... WWl, WWll, Manhatten Project, Korea, NASA pre-1955.
Even the 1970's Honeywell and Carrier factory films about Bio-HEPA, ULPA UVGI and electronic air filtration for commercial and residential applications (especially Medical and clean-room assembly)... the many US Government (NASA, DOD, DOE, and ES) instruction manuals and air system criteria for contract bidding, and the American Medical Association guideline papers on OR air recycle quality testing standards required for construction/operation.... but, not to fear folks the CDC has now discovered this 1950'-60'S "all new and shocking" way that virus can be spread.
Pun intended... I will breathe a lot easier now knowing my Government and CDC are learning all of this new stuff. Take a Wikipedia tour on HEPA - ULPA - UVGI history, and really review the history dates of this research ... whew ! ... Ignorance is contagious.