The Australian author Kate Grenville was on a book tour for her 2015 novel One Life when she started noticing the headaches. “I was having them virtually every day,” she says. “From hotels I was staying in, taxis and planes I was riding in, and also from my readers – unfortunately. I love [them], but when they wear fragrance and want to give me a hug, it can be a problem.”

Grenville began looking into the reaction she was having and was startled to find how common it was. She will be speaking at Adelaide writers’ week this month to discuss the book that came out of her experience: The Case Against Fragrance. If you’re attending, she has one plea: don’t douse yourself.

Guardian Australia: The Case Against Fragrance is an investigation into perfumes partly inspired by your own experience. How bad has it become?

Kate Grenville: The moment I’d really realised I’d gone beyond eccentric about all this was at a hotel in Launceston. The corridor outside my hotel room was very strongly fragranced with those reeds in bottles – I think they’re called diffusers – and the smell was coming in through the crack around the door. I realised I was going to have a miserable night with a headache unless I could do something about it, so I went out and found a newsagent to buy a roll of packaging tape. When all the book business was done for the night, I taped all around the door to seal myself in like a pharaoh in a tomb.

I thought: “This is crazy, I have entered some kind of planet crazy. Normal people don’t do this, so what’s wrong with me and am I the only one?”

What was the most surprising thing you came across in your investigation?

The most startling thing in the beginning was that far from being the only one affected, one in three [Americans] report health problems that can be traced back to fragrance. Many people get headaches like I do, but other people know their asthma is triggered by it, [or have] other respiratory problems – like their throat closes up or they start coughing or sneezing – or they feel sick to the stomach when they smell fragrance.

The next surprise was to find modern perfumes are mostly not made from flowers. Virtually all fragrances – whether very expensive in little tiny bottles, or the stuff you put in the toilet to make it smell nice – they are all made from chemicals.

The surprise after that was that fragrance manufacturers don’t have to declare all their ingredients, so on the one hand they can make stuff cheaply from synthetics, and on the other they don’t have to tell us. The cocktail that makes up a fragrance is considered a “trade secret”, and that’s why they are exempt from the labelling laws.

Have you noticed any difference on your current tour in the scent of your fans? Are they getting the message and toning it down for you?

They are; it is fantastic. Last book tour I had a headache every single time I stood up in front of a group of people. This time it only happened once, probably from a cab I took to the venue. The publicist is putting on the bottom of all the invitations it would be appreciated if you could refrain from wearing perfume to this event. It has made such a difference to me, I’m so grateful.

Given that this has worked out so well for you, are there any issues you are encountering on this tour that might inspire the next book?

I want to get back to writing a novel. This book was a departure for me, I’ve never tried science writing, this was fuelled by my own interest in the subject. I made a decision to only to use published science, peer-reviewed – the internet is full of rubbish about fragrance and every other subject. I had to learn how to read proper science. I enjoyed it but I needed a lot of help, and the next book is going to be another novel.

Any hints on what it might be about?

Let me just say I am still just as fascinated about the early days of white settlement in Australia. I think there are many stories that haven’t been told, we’ve only just scratched the surface. We still live with a lot of often rather self-congratulatory myths about those times.

Your visit to South Australia will coincide with the Adelaide festival run of the theatrical adaptation of your novel The Secret River. What is it like to have your work reinterpreted for another medium? Have you had any involvement in this play?

I haven’t, no. When the team that adapted the play took it on, I had a short meeting with them and I said: “Please don’t give me a faithful adaptation. A play has to be a completely different experience, please just write a good play.”

They did that a hundredfold. Andrew Bovell wrote it brilliantly, Neil Armfield and Stephen Page conceptualised and directed it. I am so proud that my work has resulted in a very different kind of experience.

A key difference between the book and the play is the inclusion of Aboriginal voices in the production. You originally wrote dialogue for the Aboriginal characters in the novel but decided in the end they weren’t your stories to tell and so it would be better not to attempt to represent them. What do you think of the decision to do so in the play?

With the book I just thought I was stepping into a world that I didn’t know enough to write about. I could imagine my way into the white settlers’ world, but the Aboriginal world – I felt first of all it wasn’t my place to tell that story, and it is extremely difficult given that not to fall into traps. So I made the decision to make it very clear the Aboriginal story was there to be told.

I think of it as like a hollow in the middle of the novel, which is where the Aboriginal story is; like I’ve drawn an edge around it in order to say to people: “Look, there is a story to be told here about the Aboriginal people whose story this also is, but it is not my place to tell it.”

When the team got together to put it on the stage, they were able to make a different decision. What I realised the first time I saw it was that this is truly a shared moment of theatre: it’s about two families, a black family and a white family, trying to occupy the same part of the planet. The Aboriginal characters are speaking in Dharug. The first time you hear them, and realise there are not going to be subtitles, you are in the same position as the white characters on stage – in other words you are watching someone talk to you and have no idea what they are saying. The audience can then see the enormous gulf of misunderstanding that happened, and will always happen.

To me it was a stroke of theatrical genius to properly acknowledge the Aboriginal reality there, and give it spoken form in Dharug language.

The play will be performed outside, at Anstey Hill quarry. What do you think the setting will add to the performance? If you could choose where people read the book, where would you like them to do so?

I’ve never seen the quarry in Adelaide, but it just looks from the photograph as if it will be an amazing experience to be out in the Australian landscape at night to watch this play, given landscape and country is what it is all about. In Aboriginal culture it is the whole foundation of the spiritual life, and it is what the conflict is about – actual country, whose country is it, how can we go about sharing it – that’s the central issue. To be literally sitting on country will be an amazing and rather humbling experience. I’ve seen the play many times and I cry every time – I expect this time to be even more emotional.

As for where I’d like people to read the book, the thing about a book is you invent the landscape as you read. Although I have to say one woman shortly after the book came out, a woman wrote to me and said: “I was reading The Secret River on a boat going up the Hawkesbury, we hired a boat and decided to sail up the river.” At one point [the book] actually went overboard, and she said: “I was so bereft at the idea of losing it that I actually jumped overboard to rescue it before it sank.” That’s dedication for you.

• Adelaide writers’ week runs from 4 to 9 March at Pioneer Women’s Memorial Garden. The Secret River is at Anstey Hill quarry in Adelaide until Sunday 19 March as part of Adelaide festival. Kate Grenville will also speak at The Secret River festival forum at the Riverbank Palais on 7 March