Inside a building we seem safe from the air polluted by car exhaust pipes, but this seemingly cleaner air actually claims more lives than the air outside: it is estimated that around 4 die each year. 3 million people because of it , when poor air quality in cities kills 3.7 million.
The reason for this fatality has a certain trick: we actually spend much more time inside buildings than outside, which is why this kind of air kills more people. But we must not forget either that bacteria, chemical compounds, fungi and pathogenic viruses infest the interior of buildings.
As explained by Prashant Kumar , from the University of Surrey and co-author of this international study published in the Science of Total Environment :
The solution is often as simple as opening the windows, but the problem would be improved if buildings had small, cheap and energy-efficient sensors that inform families or workers of the situation in real time. This way we could know when and where pollution levels increase and act accordingly.
Those who live on the ground floors have it worse, however, compared to the upper floors, and a simple way to avoid outdoor contamination is to open the windows often to air the rooms .
And, of course, not all areas of a city are equally polluted. For example, living next to a road with heavy traffic will cause the air in your home to be much more polluted. As Kumar concludes:
This aspect has important implications for urban planning, and we should consider where we want schools, offices or hospitals to be built. Many people are not even aware of what they and their children breathe when they sit in their offices or desks each day.
Also contributing to the global statistics is the fact that in the third world cooking is done with charcoal and wood, which is not advisable indoors .