That's generally a safe technique, unless you're dealing with legal issues such as livestock odor and separation distances in Iowa. Enter olfactometers and electronic noses, bits of technology still under development.
Electronic noses use sensors to detect specific gases.
Their potential uses extend beyond measuring livestock odors. The electronic nose will give an objective, consistent result that can be used to predict how people will react. An electronic nose, for example, can be used as a research tool, assessing aroma to develop a uniform food product. The trick to making an electronic nose represent a human nose is finding the correct combination of gases and relative concentrations. Using a variety of probes, one can correlate a response of sensors with various aromas.