Smelly farms may succumb to subtle science

FARMYARDS smell. There is no getting away from that. They smell because of the excrement produced by the animals which live there. And however carefully this excrement is dealt with—whether by modern versions of the time-honoured process of muck-spreading that inject it below the surface of the fields it is fertilising; or by anaerobic digestion, in which it is used to make methane that can, in turn, be employed to generate electricity—it is still the case that the buildings housing the animals themselves stink.

Besides being unhealthy for farmworkers (not to mention the neighbours, if the farmyard is near a village), such smells are bad for business. Research has found that improving the air quality of the places where pigs and other livestock are housed makes for healthier and more productive animals. The question is, how to do that cheaply? Jacek Koziel of Iowa State University reckons he has the answer: titanium dioxide and disco lights.