Checking your mobile and ordering a latte might seem ordinary 21st-century activities but nonetheless I am astonished to see Pat Thomas doing them when I meet her. After all, mobile phones and coffee are just two of the many things she demonises as environmental hazards in her latest health book Living Dangerously: Are everyday toxins making you sick? You name it, this tireless American environmental health campaigner has blacklisted it: perfume, loo cleaner, television, make-up, showers, carpets. On top of these are the more familiar modern scourges: pesticides, car exhaust fumes and industrial waste. You are left wondering how anyone on the planet has survived.

But Thomas does try to maintain a realistic view of modern life. When I challenge her about the mobile and latte, she exclaims: “You want me to be a paragon?” Her book opens with a table illustrating a typical toxic 24 hours and the airborne pollutants, EMFs (electromagnetic fields), hormone disrupters, pesticides and toxic metals to which we are exposed. You may think you’ve got off to a good start when, having been woken by your radio alarm, you take a shower, brush your teeth, put on clean clothes, make a cup of tea before checking your e-mails and jumping on the bus to work. You are wrong.

By this stage your body will be polluted by a combination of environmental poisons; the cumulative effect, day in day out, writes Thomas, is that you may be “one of the millions of people throughout the world who are suffering from vague, ill-defined but debilitating health problems such as headaches, sinusitis, depression, mood swings and digestive difficulties”.

Thomas is no hairy hermit. She admits that she lives in a house (as opposed to a cave) in northwest London and that it has its quota of electrical appliances. “I don’t want to turn back the clocks. I’m a city girl. But I don’t want to have to cope with having cancer or diabetes later on. I want to see my grandchildren, so I make sure our use of things is safe.”

Thomas makes her own cleaning fluids from baking soda and water. It will never catch on, I say: it’s cranky and time-consuming. “I have an action-packed life, I am not a pampered housewife,” says Thomas. “I am a single mother. It just depends on your priorities.”

Environmental health wasn’t a priority for Thomas’s former cleaning lady. “She mumbled and groaned when I got her to use my cleaning fluids,” says Thomas, “but the house got clean.”

I bet it didn’t smell as good as a freshly Gleemo-Kleened kitchen. Thomas is not impressed. “Do you want your house to be cleaned or perfumed?” she asks and launches into a tirade about the horrors of air-fresheners.

She tells me about a woman who was having sleeping problems. Her doctor prescribed Prozac. The symptoms got worse, especially in the bathroom where the dizziness and nausea would intensify. “It turned out her mother had left an air-freshener in the bathroom,” she says. Once it was removed, the symptoms disappeared. It does not surprise Thomas that the GP sent her home with Prozac. “They aren’t trained in environmental health,” she says.

There are only 3,000 environmental-medicine practitioners worldwide. They believe the environment determines our health. They blame the rise of diseases such as asthma and cancer on our “toxic” environment.

There is, however, good news: our homes may soon become a little less toxic courtesy of the bureaucrats of Brussels. The European Commission unveiled plans this week to enforce the testing of all household chemicals before sale and the banning of the more harmful ones.

Before I met Thomas, I touched up my lipstick and sprayed on Rive Gauche. She makes me wish I hadn’t. “Perfumes,” she says, “are of the nastiest kind. They should carry a health warning.” As for make-up: “It contains every chemical in my book,” she says, as I try surreptitiously to wipe a hand across my poisonous lips.

By the time I’ve read Thomas’s chapter on stress-inducing EMFs in the home, I am close to despair. It seems there is nothing for it but to put my name down for a cave in the wilderness.

“You need to start with what’s workable,” she says. “To give up your car might be unthinkable; ditching the microwave might be easier. It might be unthinkable to go out and not wear perfume but you don’t have to wear it all the time.” Has she ditched perfume? “No,” she says, “I wear it for special occasions. Sometimes people say, it’s whine , whine, whine — you’re taking away all the fun. But that’s just teenage. We are making such a mess of the world that we need to take an adult view.”

• Living Dangerously: Are everyday toxins making you sick? (Newleaf, £12.99)

Next page: be afraid, be very afraid

()BE AFRAID, BE VERY AFRAID

Once upon a time, we had only plague, pestilence and predators to worry about. Now, Thomas says, threats surround us:

Just walking across carpets exposes you to a range of airborne pollutants, hormone disrupters, pesticides and toxic metals.