Enviromental Sampling of Volatile Organic Compounds

During past and this summer, I have been able to smell the backyard hives, but the human nose is not designed to quantify or map a smell - see this link about Olfactory Fatigue.    Here's how I compared the smell of 3 hives and compared each hive smell to background using a Volatile Organic Compound (VOC) sensor.

I purchased 2 breakout boards by adafruit, one measures VOC concentration and the other measures temperature and humidity. Seen in the photos:

• two breakout boards plugged into a mini stick-on breadboard
• red colored sparkfun arduino microprocessor attached to an upside down white plastic storage lid using black nylon standoffs by adafruit
• a mini serial cable connecting the microprocessor and laptop
• laptop attached to the ladder's paint-tray using a bungee cord

 

My first backyard environmental measurement of VOC was meant as a dry-run, but luckily I did not need to modify my experiment design:

• chalk marked or flagged a 6 x 4 grid surrounding 3 hives - 4 grid points are skipped due to large shrubs
• selected a day with no wind so as not to disperse the VOC which pool near the hives
• selected an evening to avoid when most flowering plants produce VOC
• warmed-up the sensor system outdoors for an hour before sampling
• setup at a grid point, and sampled for 60 seconds. I stepped away from the 6 x 4 grid during sampling as my body both produces and disperses VOC
• after sampling 20 grid points, I repeated the first 5 grid points to examine reproducibility
  

A few words of explanation regarding the map of VOC surrounding 3 backyard hives:

• VOC are shown in parts per billion (ppb) units.  As I do not have access to a reference gas mixture, you can think of these VOC values as relative values.
• The central (middle) hive had the highest concentration of VOC.  This hive is a massive stack of boxes with 2 queens separated by a cloake board.   On the bottom of this stack is an over wintered hive.   On the top of this stack is a medium size swarm catch (March 23, 2020).
• A VOC plume from the central hive merged with the hive shown at the bottom of the map.  The hive at the bottom of the map is a large overwintered hive.
• The hive at the top of the map is inconsequential in VOC production and resembles a background value.  This hive is a tiny swarm catch (March 13, 2020).