How does the design of our buildings and office layouts need to change to minimise the spread of COVID-19? That's one of the questions exercising Joe Allen, an assistant professor of exposure assessment science and director of the Healthy Buildings program at Harvard University's T.H. Chan School of Public Health. He's interested in the way our offices, homes and other enclosed spaces (including aeroplanes...and toilets!) could be contributing to the spread of COVID-19. An early advocate of facemasks to limit COVID's spread, he's a critic of needless 'hygiene theatre" at the expense of tackling what he sees as the single most important issue: airborne transmission. One of the answers? Better ventilation systems, with a host of air conditioners and filters being retrofitted in American office buildings to help coax uneasy workers back to their desks. So what lessons can we learn from this here in New Zealand? And how far should building owners and employers be expected to go to ensure that their staff stay safe and well?