In terms of wine and flowers, it can be said that "the nose knows." Now there's another area in which the sense of smell is making an impact. China, known for it's choking smog, is conducting research into air pollutants by having researchers smell air samples. Being able to determine the source of pollution is key to improving air quality.
Local officials in some of China's most heavily polluted areas are relying on the human sense of smell to identify the sources of pollution. While there are more advanced techniques, like spectrometry and chemical analysis, the smog sniffers usually get it right. Because winds can shift and weather patterns can change, having human sniffers speeds up the process as well. Samples can be collected and categorized, with reports going to area environmental monitoring agencies in a matter of days. There is a small risk to the sniffers of respiratory issues, but not much more than just living in an area that is heavily polluted.