There is an article I have seen posted on Facebook a couple of times that highlights the health risks of synthetic fragrance ingredients. I won’t link to it, but if I am seeing it there is a good chance you will have seen it too. The thesis it proposes is that synthetic chemicals in fragrances are toxic and might be dangerous to people who inhale them in public places, even if they aren’t actually wearing the fragrance themselves.Well this is scary stuff. The article isn’t particularly well supplied with detail so let me contribute some facts to the proposal. For a start, it is true that the lungs are a good place for certain chemicals to get absorbed into the body. If you can breathe something in, then the large surface area of the lungs with its rich blood supply is a very effective way of getting stuff into your bloodstream from where it is rapidly distributed around your entire body. It isn’t as easy to get large quantities in as it is via eating them, and it is a bit more selective about what can be absorbed than the skin is. But against that you have to take into account that while you can avoid eating things and touching them, you really can’t get by without breathing for very long.
And it is certainly true that there is plenty of stuff in the air that gives cause for concern. For a start there are particles of dust from both natural and manmade sources which can cause severe medical conditions up to and including death under the wrong circumstances. And there is pollen – this plays havoc with people prone to allergies to particular pollen. Modern farming techniques often involve growing a lot of the same plant in a small area, so this can be a great nuisance. And then there are fumes from exhaust pipes, power stations and jet engines. There are plenty of potentially troublesome molecules to be found there. And on top of regular sources there are also one off events like the testing of nuclear weapons which we know spread radioactive waste around the world. Even things like really big bombs, like the one dropped recently in Afghanistan, might well create new molecules we haven’t yet studied.
So all in all the air that we breath is an important source of things we need to be concerned about. There is a lot of science to be done, and a lot of regulations that would be beneficial to everyone. And any chemist will point out to you that the thing with molecules is that they are very small and very mobile. And there are lots of them. When a Japanese nuculear reactor released some unique ones into the atmosphere it was only two days before they were detected in Great Britain on the other side of the world. In fact there is a good chance that they reached Britain sooner than that. The atmosphere is a common asset that everyone on the planet shares. If there were no other reason to found it, good management of the atmosphere alone would justify the creation of the United Nations.
So as I am so interested in what is in the air, and in how we keep it clean you might imagine that I would be right behind a campaign to keep synthetic fragrance ingredients out of the unsuspecting lungs of members of the public. But I am afraid this is not something I feel the need to join in with.
I am not inclined to include fragrances in with the quite long list of potential problems that we face simply by breathing. For a start there is one simple bit of logic. Most chemicals are not dangerous. This is just as well given that we are made of them and so is everything we come into contact with. But the plain fact is that we have bodies that have evolved on a planet that is full of chemicals and we are pretty good at handling most of them. If you pick a group of chemicals at random most of them are going to be quite harmless. And in fact the chemicals that happen to have appealing smells to our particular noses are just that – a random sample. There are lots of molecules that are very similar to the ones that are used by perfumers that don’t smell at all. So there is no obvious case for why fragrances should be especially dangerous.
I am simplifying a little here. Some things that are not in themselves dangerous can be deadly if you have enough of them. Sodium chloride is fine when applied at low level to fish and chips, but can kill you when injected at a high enough concentration. But this does not really apply to fragrances. You can smell things at very low levels indeed. Some substances can be detected when their concentration is only few milligrams per 1000 tonnes, which is less than a drop in an Olympic swimming pool. So just because you can smell something doesn’t necessarily mean you are getting a large dose of it. Generally you are not.
But what about the overall effect of lots of people using lots of fragrances and letting them all loose into the air where other people are exposed to it? And what about the overall effect on the planet of all these chemicals? Well in the first case there is a pretty well established relationship called the inverse square law. As you get further away from a source of something the signal gets weak very quickly. The light from a candle is often used to illustrate this. You can’t read a book from a candle that is situated on the other side of the room. Put it on the other side of a field and you can’t even see it. Even the most fragranced up overblown tart won’t be detectable once you get a couple of meters from him or her.
And fragrances are a pretty low proportion of industrial production overall. I don’t need to refer to official statistics to work this out. Just look at the average shopping basket. People just don’t buy fine fragrances very often.
Nonetheless there are people who report severe reactions to fragrances they encounter in public places. There have even been moves to create places that are free from them for the benefit of sufferers. It is conceivable that somebody who was very sensitive to a particular fragrance component could suffer an allergic reaction to it if exposed to it in a confined place. I can’t imagine that this is at all a frequent occurrence, but that is not much comfort for the particular individual affected. I have a feeling though that most reactions like this reported in are not directly down to fragrances at all.
I think it is much more likely to be reactions to other chemicals, and I would hazard a guess at a couple of likely culprits. The suspect pair are formaldehyde and methylisothiazolinone that are used as preservatives in paint. Both are quite safe for this application from a purely toxicological point of view. But allergic reactions can sometimes be triggered off by very low levels of an allergen indeed. It is one of the things that varies a lot between individuals.
An area of an indoor shopping centre that has recently been painted might well have a low level of the preservative from the paint.
So I think that paint is likely to be a bigger problem than perfume. This is bad news – paint is used in much larger quantities than fragrance so if I am right the problem is much larger. It is also harder to solve. I don’t know much about paint formulating, so I don’t know if there are better alternatives. But the first stage in any problem solving exercise is making sure you have the analysis correct.