I t is ironic that, having spent years on cleaning up at least the visible pollution in outdoor air, concern should now focus on indoor air quality. But it is not that surprising: we spend 80-90 per cent of our lives indoors. In this week's article on risks and next week's on remedies we focus on the non-industrial environments where air quality is little controlled. Here many of the risks have only recently become a worry, some are ill defined, appropriate air quality standards are different to industrial ones or even as yet unformulated, and so enforcing standards is likely to be problematic. The action to be taken by designers is sometimes clear, sometimes not.