Some information regarding sensitivities/allergies:
Source: (unknown how reliable)
http://www.dailymail.co.uk/health/article-458357/Runny-eyes-wheezy-chest-Blame-Britains-crops-rapeseed.html

"....researchers say many people mistakenly blame their symptoms on pollen from the plants. According to the National Pollen and Aerobiology Research Unit in Worcester, only one in 25 people tested for rapeseed allergy actually reacts to the plant. Instead, many become ill due to gases - called volatile organic compounds - emitted naturally by oils in rapeseed when it blooms.

One study at the Scottish Crop Research Institute in Dundee in the mid-Nineties found that rapeseed emits 22 different volatile compounds. Many are known to cause respiratory problems. The major culprits are chemicals called terpenes, aldehydes and organic disulfides. Terpenes give many plants and fruit their distinctive smell.

Another study at Aberdeen University tested 37 people who complained of wheezing and blocked airways due to rapeseed. Only two had any evidence of allergy when exposed to the pollen. But most still showed signs of lung irritation and wheezing from the plants.

Maureen Jenkins, of Allergy UK, said: 'Rapeseed produces volatile oils in the atmosphere which irritate sensitive airways. Anyone with hayfever or asthma may find symptoms worsening if passing a rapeseed field because of these volatile oils in the air. 'Keep car windows closed when rapeseed is blooming, especially if you have hayfever or asthma.'

Beverley Adams-Groom, of the National Pollen And Aerobiology Research Unit, said the fumes are known to irritate the airways. 'These compounds cause a very strong smell and trigger flu-like symptoms in some people,' she said. 'We know of families living next to rapeseed fields who feel ill when the plants are flowering.'
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I do know that many people have a similar reaction to lily and paperwhite narcissus scents.