In the southern parts of the country there is a smog resembling a smog.
"This is the sand of a sandstorm in the Sahara a week ago. The sand was then transported into the higher atmosphere and brought here by rapid, strong winds, says Max Elmgrin, environmental investigator at the Stockholm city administration.
Microscopic particles is just extremely small sand grains – 2.5 microns in diameter. The most common particle source of this size is carbon burning. Living cells typically have a size of about ten microns in diameter.
– Since the mist is largely composed of quite small particles that are more dangerous to health, the air quality is quite poor. So people who have asthma problems can feel quite big problems today and need additional treatment, says Max Elmgrin.
Particles, for example from exhaust gases and the cars that break the asphalt are larger and then the body can prevent them from causing problems themselves.
"The smaller ones penetrate the lungs, and if they are small enough, they get into the blood," says Elmgrin.
Background levels in Stockholm are five times higher than normal, from ten micrograms per cubic meter to 50-60 micrograms per cubic meter.
Meteorologist of SMHI Moa Hallberg confirms that the weather graphs show that the particles come from the Sahara. The big movements in the air systems have made the sand absorbed in the north and also affected countries such as Denmark, Germany and Poland.
But the mist may have other reasons.
"She's also moved to a warm front to get the wetter air," she says.
The fact that the Sahara sand is swept away is relatively unusual and occurs somewhere in southern Sweden every year but rarely further north of Stockholm, according to Max Elmgren. It is expected that high levels will continue for one day, and advice for those who are sensitive may not go on a long, long walk.
Time does not change the next few days. Until he starts blowing elsewhere, he's probably left out, but he can get shocked.