No smoking, no perfume, no mobile phone use - the list of rules at a newly opened apartment building on Zurich's outskirts is long.
For a reason: the structure has been purpose built for people who say exposure to everyday products like perfume, hand lotion or wireless devices makes them so sick they cannot function.
"I have been suffering since I was a child. This will really move my life in another direction," said Christian Schifferle, the 59-year-old head of the Healthy Life and Living Foundation, the prime driver behind the project.
Schifferle and the other residents suffer from Multiple Chemical Sensitivity (MCS), a chronic condition not broadly recognised by the medical community. Those afflicted, however, believe it is sparked by low-level exposure to chemicals in things such as cigarette smoke, pesticides, scented products and paint fumes.
Twelve of the 15 apartments in the earth-coloured building in a remote part of Leimbach, on the outskirts of Switzerland's largest city, have already been rented since it opened in December.
Many occupants also suffer from electromagnetic hypersensitivity, in which electrical circuits and radiation from wireless equipment make them ill.
"It makes me weak, anxious, I can't breath, my lungs hurt, and I get dizzy," says Schifferle, who suffers from both conditions.
While living in the building will not cure Schifferle or others, it aims to make daily life more comfortable for people whose conditions have often left them isolated and unable to hold jobs.
Schifferle, who first felt sick from the fumes in his parents' furniture factory when he was three or four, has lived most of his adult life in a trailer in the pristine Swiss Alps.
It was not until he was 35 and stumbled across an American book on MCS that he realised he was not alone, but it was another decade before he found a doctor who took him seriously.
"All my life it has been like I was only half alive," he said.
The new building is the first of its kind in Europe, according to Zurich officials who decided to play a pioneering role in helping people with what they called "a very harmful problem". They say about 5,000 people in Switzerland alone suffer from MCS.
The city made available the land and gave interest-free loans to help finance the 6.1 million Swiss francs (HK$53 million) project.
Anyone entering the building is expected to switch off their mobile phones, which in any case do not function inside. But there are landlines for telephone and internet communication.
Near the entrance, the only cleaning and personal hygiene products residents are allowed to use are on prominent display.
The building was built with special materials, by purpose-trained builders banned from smoking or using scented products like cologne as they worked. It has a ventilation system aimed at sucking out all odours.
The floor plan is layered like an onion "so that the deeper you enter the apartment, the cleaner the rooms get", architect Andreas Zimmermann said.
The building's most "contaminated" parts are the common areas, main hallway, stairwell and elevator in the centre.
From there, residents enter their apartments, moving through a hallway where they can remove "polluted" clothing, the bathroom and kitchen or other technically equipped rooms, before getting to the "cleanest" rooms: the living room and bedroom.