According to the Economist it is the 110th anniversary of airconditioning.”Precisely 110 years ago in Brooklyn, on July 17th 1902, in the middle of a warm and wet summer, (Willis) Carrier signed off on the final drawings of what within a few weeks became the world’s first modern air-conditioning unit.” New developments in airconditioningunits could help to filter CO2 from our cities. “The industry is in the process of rediscovering CO2. Nowadays, diesel engines and other piped systems are built to withstand pressures substantially higher than those which caused carbon dioxide to fall out of favour. Like CFCs and HCFCs the gas is non-toxic and non-flammable. It is also all too abundant. John Mandyck, a vice-president of modern-day Carrier, says the company has already begun rolling out its first CO2-based products. They extract the gas from the air, making them carbon-neutral and easy to replenish in the event of a leak…”Plenty of homes still rely on HFC-based units for now. But that will begin to change as the devices reach the end of their useful life and regulators insist on switching over to greener alternatives”.