How do you study it?
When we analyze odor samples we do it with two simultaneous methods. The first way is a chemical analysis that allows us to identify and quantify the chemicals in the air. The second way is to your nose to a sniff board and actually sniff each and every compound that constitutes the air sample, allowing us to determine the compound that carries the specific overall odor of any sample. That's why, in my opinion, there is no need to mitigate the hundreds of compounds in pig odor, because not all of them are responsible for that odor. There are only a handful that we need to go after: I call them the "bad guys."
How do we stop the worst components of pig odor?
My group has shown that high-energy ultraviolet light works very well in laboratory settings. We would like to move up to the commercial scale. The light induces chemical reactions that change these offensive odorous compounds into something benign or at least less smelly. This is one of those technologies that would work not only for livestock-type odors but also on different types of odors, say office or residential odors.
Or my own bathroom?
Yes, of course. There has been some research on the use of ultraviolet light in some critical environments, because UV light is also capable of inactivating airborne pathogens. You can envision this technology being used for all sorts of odors we know from daily life: bathrooms, gym lockers, crowded offices, and such. This is something that can be beneficial in many different areas, because many of these odor-causing chemicals are similar, and it doesn't matter if it's of livestock or human origin.
Are there any other techniques to reduce pig odor?
There is a more mature technology that I have also worked on in collaboration with Steven Hoff, a colleague at Iowa State. He's using biofiltration, which uses large beds of wood chips that harbor microbes. As air passes through the chips, the microbes are eating up the odorous compounds. That technology has proven to work quite well in real livestock operations.
The team at ARS also works on the nutrition side to reduce odor using additives or micronutrients. For example, the scientists will change the sulfur or nitrogen content, and they also work on tweaking the microbial flora in the gut. When you do this, however, there is always a danger of affecting animal growth, metabolism and how much meat they produce.
How did you start studying pig odor in the first place?
I did my PhD way back at the University of Texas in Austin studying sewers, so that was my introduction to smelly things. We worked on emissions of gases from sewer collection systems in pipes carrying human waste. After that, I went to Canada to work with at the University of Waterloo, and I learned this analytical technique called solid phase microextraction for sampling minute amounts of gases. That's sort of where the story with pig odors starts. Many of these odor-causing chemicals are detectable by our noses at low concentrations. The technology I learned in Canada moved me into this area in livestock. Also, growing up in Poland, I worked each summer on a small farm. My grandfather had all sorts of livestock so this all comes back to me.