I don't get much time these days to connect back to my academic training. But next week I'm headed to Kern County and John Karlik has proposed that we spend some time talking about air quality. Now, given that this is California, I suspect John is thinking about particulate matter. Dust and particles are interesting but odor and olfaction are where the real excitement lie. Consider this:
- Olfaction (the science of smell) is the least understood of the five senses
- At the age of 20, the average person retains 80% of the olfactory acuity that they had at birth; at age 80, the average person has only 20% of the capacity they had at birth
- Children under the age of 5 often rate the smell of feces as pleasant suggesting that they may detect compounds that adults may not or that the unpleasantness is learned
- Humans possess far less sense of smell than other mammals
- Odor is the response elicited from a mixture of compounds, each of which is an odorant
- The difference between the concentration below which an odorant can't be detected and the concentration above which an odorant is overwhelming to the senses such that it can no longer be detected may be as low as ten-fold, compared to other senses that have a ten thousand-fold or greater difference
- Women have a keener sense of smell than men
- Smoking dulls the sense of smell
- Odor fatigue refers to a temporary situation when a person can no longer distinguish a specific odor due to prolonged exposure (nose-blind)
- Anosmia refers to a condition where a person can't detect a particular smell (odorant) regardless of the concentration
- One in one thousand people can't detect methyl mercaptan – the compound that is often used in propone tanks as an alert when the propane level is low
- One in ten thousand people can't detect ethyl mercaptan, the primary odorant in the spray of skunks
- Odor is a conditioned response; in blind studies, panelists often rate the smell of chocolate as 'unpleasant' (I happen to be one of these people) but when told that the smell is chocolate they rate the odor as 'pleasant'
- How odorants interact to create odor is poorly understood thereby making odor and odor nuisance difficult to predict
I don't want to stir up too much excitement over the topic so I'll hold off sharing manure-specific facts until some other post. Needless to say, I welcome the chance to talk about air quality a bit. Occasionally I do have the opportunity to talk about air-related things. This morning started off with a conversation about enteric methane emissions. I'll be part of additional conversation on that topic and other greenhouse gas emissions in a couple of weeks in DC, if we can avoid further government shutdowns.
I ran into Yolva and Claudia on my way out of the Davis ANR building this evening. I didn't want to keep them too long because Russell, Steven, and others from the Latino Initiative were waiting but they updated me that Malena and her mom had a great time at the Regents meeting and Malena's club were excited to hear all about her big adventure. I also learned that Malena has always wanted to attend Berkeley so she was well-prepared for President Napolitano's question. Once Malena enrolls at UCB, we'll have to be sure to lure her towards a career with UC ANR!