I doubt these sensors would tell you an amount of pesticides in air. They are not specific enough for that. Pesticides don't produce particularly these gases, but harmless compounds or activities do.
Additionally, many pesticides are little or not volatile, in order to act for long. If they stay on plants as a powder, film or droplets, you'll notice very little pesticides in the air, but bees touching the plants will be contaminated.
One general idea to analyse small concentrations of air contaminants is to suck much air through a filter, then analyse the filter. Or if enough contaminated bees find the way home, what about analysing their landing place?
A more specific detector might pass light through a long air distance, possibly with mirrors and many passes, and observe the absorption spectrum. This might work, but only with pesticides volatile enough, and is significantly more complicated than a handful of gas sensors.