Theme ‘smell’

Smell’ is a theme in the chapter ‘interior design’. (See the recommendations.)
Scientific study into autism and smell is scarce, although olfactory oversensitivity is a well-known fact in practice. An estimated one third of people on the spectrum suffers from it to a serious degree. In a poll by Magda Mostafa among parents and teachers of autistic children in which they were asked which of six factors had most impact on their children and pupils, no one put smell first. This doesn’t mean smell is unimportant, but rather that particularly noise and spatial arrangements were viewed as most important.
The impact of smell is easier to imagine if one realizes its inescapability. We can turn away from visual stimuli, unpleasant touch, and foul tastes can also be avoided. Even sound can at least be shut off partly by earplugs, while one is defenseless against smells in spaces one cannot avoid.

Olfactory (i.e. smell) sensitivity is often selective, concerning only specific smells. As the autism is more severe, so is generally the oversensitivity for odors. Donna Williams introduces ‘Jake’ who suffers from sensory hyper-sensitivity and finds perfumes intolerable. He avoids having meals with others because of their body odor and the smell of the food. In cases of less severe autism such experiences can disrupt daily life much more than when a normal child doesn’t like its food.

One of the collaborators of the Dr. Leo Kannerhuis says about one of her clients: ‘She has great difficulty to come or stay in the outpatient building because she’s greatly bothered by different perfumes and aftershaves worn by my colleagues and also by the smell of food in the building. Another woman has a lot of trouble with office buildings because she finds the smell of the carpeting and machines such as printers intolerable.’

An architect who has worked with the Kannerhuis points out that new buildings often have the smell of paints and carpeting, the latter mainly emanating from carpet glue. If this is a problem, extensive ventilation before taking the building into use, is advisable.

So at times the source of vile odors can be avoided or kept out; in other situations such as the kitchen or the toilet they can’t. This is particularly true for spaces, among which schools, where many people assemble, because bodily smells are among the most unbearable to people with this sensitivity.

Body odor
The link between the CO2-concentration (see the next paragraph) in a space and the experience of body odor is known for more than a century. Adults generally do not experience odor below concentrations of 1500 ppm (particles per million). How children experience this we don’t know. We do know however, this level is exceeded by 500 ppm in the average Dutch elementary school.
In a Danish experiment the percentage of students who experienced the body odor as ‘unacceptable’ upon entering a lecture hall increased from around 20 to 30 percent, after the CO2-concentration went up from 600 to 1,500 ppm. Usually there appears to be a ‘natural adaptation’ to the odor in about fifteen minutes.

Air quality in schools
The point of departure for the assessment of air quality is the carbon dioxide- or CO2-concentration. Not because this compound is in itself harmful but because it displaces oxygen which offers opportunities to all sorts of other compounds among which noxious ones. The norm for the CO2-concentration in schools is 1200 ppm (particles per million), while the average concentration in Dutch elementary schools is 2000 ppm; no less than 80 to 88% of Dutch classrooms exceed this norm. The situation in European and Western countries generally is by and large the same. As a result smell annoyance, eye irritation, headaches and excessive fatigue have been found among numerous other health problems. Absenteeism is stimulated by this and educational achievement lowered. Both effects have been established in research but those about academic achievement aren’t entirely clear and need further study.
The Dutch Health Council “is of the opinion that odor nuisance detracts from a feeling of well-being and that it should be limited as far as possible, even upon entering the classroom. The Committee assumes that studies generally showed that a few percent of those questioned also reported experiencing annoyance during extremely low levels of exposure.”

Among those ‘few percent’ will undoubtedly be autistic students who have an oversensitivity to smell. Furthermore, it’s an open question to what extent students on the spectrum will also experience a ‘natural adaptation’ to odors. Several autistic characteristics might interfere in such a process, among which ‘shifting’ and other mechanisms behind a general lack of flexibility. (See autism characteristics.)

Any ‘odor policy’ would involve the keeping out, avoidance or the isolation of noxious smells. All these are difficult to realize in a home, school or any other building.
In all the cases in which prevention of smells which are subjectively experienced as annoying or worse is not sufficiently possible, effective ventilation is by far the most effective option.

According to Baron-Cohen, Simon, Emma Ashwin, Chris Ashwin, Teresa Tavassoli and Bhismadev Chakrabarti, ‘Talent in autism: hyper-systemizing, hyper-attention to detail and sensory hypersensitivity’, In: Philosophical Transactions of Royal Society. Biological Sciences (2009) (July), 364, 1377–1383.
Mostafa, Magda, ‘An Architecture for Autism: Concepts of design intervention for the autistic user’, In: Archnet-IJAR, International Journal of Architectural Research 2(2008) 1 (March) 189-211. This is part of the ‘core literature‘.
Williams, Donna, Autism – An Inside-Out Approach, London and Philadelphia, Jessica Kingsley Publishers, 1996.
body odor
Most of this and the next paragraph is derived from: Health Council of the Netherlands, Indoor air quality in primary schools. And the value of carbon dioxide as an indicator of air quality. The Hague, 2010. To be downloaded here.