The achievement of a kind of ecological human niche, in such environment, makes it necessary to build a selective protective envelope with a suitable shape and to locate this in a well situated place. It is essential to implement a bioclimatic architecture, more efficient in terms of energy, amongst other criteria, and more isolated from the various sources of pollution while trying to reduce as much as possible the production of kitchen waste. This envelope must be made with specially chosen materials, best suited to a healthy biological building, in other words a Bio-building.

Quality of the air : chief contemporary chemical pollutants (*)

Contemporary chemical atmospheric pollution is characterized by the presence of abnormal quantities in the air of sulfur dioxide (SO2), of nitrogen oxides (NOx), suspended particles (SP) or black smoke (BS), of volatile organic compounds (VOC), of carbon dioxide (CO2), of carbon monoxide (CO), of ozone (O3), or also chlorofluorocarbons (CFC), of lead (Pb) and other elements according to regions...

Evolution  -during the last fifteen years-   shows, for example, that concentration in SO2 (mainly coming from the systems that produce heat, both for the satisfaction of direct household needs and for power stations, but more so for industry) has been reduced by half in most Western cities. At the same time, NOx has remained more or less steady, but may have even increased on account of the growth of car traffic (the chief producer of nitrogen oxides - 60% to 75%).

Taking into account ozone (O3) of the first atmospheric layer (or "bad ozone", as a harmful photochemical pollutant) can be a sign of this evolution of the quality of ambient air, since tropospheric ozone is caused by the interaction of ultra-violet rays (U.V.) and the emission of other pollutants (nitrogen oxides NOx and carbon monoxide CO, mainly coming from vehicles for 60-70% on the one hand, and, on the other hand, suspended dust or black smoke BS and certain volatile organic compounds VOC, whose sources are both means of transport and industry).

Besides, it is perhaps necessary to specify that the stratospheric ozone layer forms a filtering zone about 30 km from the ground ; it filters through the U.V.-B radiations (that is why it is called "good ozone"). Since the 1980's the thickness of this ozone layer has seemed to decrease at the South pole every spring, particularly on  account of the abnormal presence of halogened derivatives  (such as the CFC : chlorofluorocarbons and other less halogened compounds), which release chlorine, the element which is responsible for the destruction of part of this stratospheric ozone. The nitrogen oxides and certain volatile organic compounds VOC (methane) might equally play a part in such destruction.

It is also necessary to point out the fact that the atmosphere is receptive to solar radiation, indispensable to life, and that the ground thus heated emits an infrared radiation trapped by the gas causing a greenhouse effect (CFC, CO2, VOC : methane, N2O : nitrous oxide, ozone, water steam) ; this phenomenon might warm up the Planet. Since the beginning of the century, the temperature of the atmosphere has risen by 0,5 ° C ; but, it is not possible to relate this thermic growth to human activity or to natural climatic variations with certainty, even if many Scientists nowadays   favour   this   thesis.  According  to  certain prospective  studies,  this  rise  in  the temperature of the atmosphere would reach 1 to 4 °C at the dawn of the XXIInd Century ; this means that during the next century, the effect on thermic insulation of buildings, amongst other things, will be much less important than the foreseeable consequences on flora and fauna, particularly, according to areas in this modified "natural" habitat.

Going back to tropospheric "bad ozone", -in a rough approximation- as the indicator of contemporary chemical pollution. This is formed in masses of polluted air, which is carried away so that its harmful effects may he more frequent outside towns, in the smoke of urban industrial pollutions or around main roads. Peculiar climatic conditions (very bright sunshine, stagnation of the air : no wind) often worsen this phenomenon. However, to give a full idea of the situation let us remark that a part of the ozone formed in town is immediately destroyed by certain nitrogen oxides.

Concentrations in tropospheric ozone were about 20 µg/m3 at the beginning of the century ; nowadays, they may rather commonly reach 60, 80, even 100 µg/m3 on average and sometimes more. For the Superior Council of Public Hygiene in France (Information dating from 27th April 1995), the threshold of protection for health averages 110 µg/m3 (an average for eight hours). From 180 µg/m3 on, populations must be warned of the risks they run.

Such concentrations, indeed may cause headaches, local ocular, bronco-respiratory irritations, together with a decrease of the function of respiratory ventilation, especially in allergic persons more sensitive than others ; they maintain and even worsen the disease in asthmatics notably. In time of photochemical pollution, physical activities should be controlled, even stopped for hypersensitive persons, in zones where the threshold of information is frequently exceeded (superior to 180 µg/m3). In case of optimal pollution, the habitat even becomes a real sanitary refuge, particularly for children and fragile subjects, since they are advised to avoid going out during the hottest and sunniest hours of the day.

- From "communicative" radio frequencies...

                                         to low "computer" and "electric" frequencies

The sources of électro- magnetic radiation have considerably increased during this century, both in their variety and intensity, so that some persons now speak of an "electro-smog", or a real electromagnetic artificial fog around the Planet, up to very high altitudes on account of the putting into orbit of more and more tele-communication satellites.

We are nearly everywhere invaded by the radiations of radar transmitters and others, those coming from television sets in U.H.F. (hyper frequencies from 0,3 to 3 gegahertz) and cell telephones (GSM : Global System for Mobile communication of 925 and 1800 megahertz), mobile phones (with their 300 megahertz aerials) then those caused by   television   sets   in   V.H.F.  (from  30  to  30 0 megahertz), radio waves FM, AM, and receivers (cathodic screens, for Very Low Frequencies : V.L.F.) ; neither, must we forget the electric, electromagnetic fields (for Extremely Low Frequencies : E.L.F.) of domestic appliance or others, of electric networks of distribution and supplying as well as high tension lines and lines of transports electrically drawn.

To face all these forms of invisible energy, numerous scientists are wise enough nowadays to warn the populations of the sanitary risks caused by this exposure in various areas of the Planet, by recommending as often as possible prudent avoidance. In addition to the chemical "Smog" in certain regions, an "artificial electromagnetic fog" prevails, omnipresent and invisible, but not inactive on living bodies according to their own sensitiveness.

- Radio frequencies : micro-wave ovens or hyper frequencies

                                                                              and mobile telephones

The frequency of the wave carrying mobile telephones is of about 900 or 1800 megahertz, according to the types of networks. The telephone constantly emits to be detected if it is not disconnected. This detection and the transmission of calls are established through a relay, covering a spatial zone of diffusion or cell (that is why it is called a cell network), whose radius varies from 5 to 20 km around each relay in open country and goes down nowadays to a minimum radius of about 1,5 km in town. The emission is however all the more  important as the network is more in demand and it reaches all the persons standing in its diffusion-sphere, even those who do not own any mobile telephone. Of course, its users are more exposed, especially the organs close to the telephone during calls. What matters particularly, is the density of the power. It is   most   often   expressed   in   microwatt / cm2   (µW / cm2).

During a phone-call, the user  receives  an average  density of power of 1000 to 2000 µW/cm2 ; now, Professor W. Ross Adey (President of the National Council on Radiations Protection in USA), asserts that power-density inferior to 10 µW/cm2 may have a disturbing effect on cell cultures and laboratory animals. Professor Neil Cherry (Lincoln University, Christchurch, New Zealand) even say that the threshold should be inferior to 0,1 µW/cm2 !

Certain firms acknowledge the potential dangers of these cell-phones ; in fact, one of them uses slogans related to those risks to position its products commercially.  Measurements performed on an emitting GSM Hagenuk show, for example, a power density more than ten times inferior to that emitted by GSM produced by rival firms. But, there is still a lot to do to reach absolute safety, since we still note -with this type of telephone- 200 µW/ cm2 at the brain-level during a call.

- Very Low Frequencies (V.L.F.)  

                                      and cathodic screens of computer or T.V. sets

While waiting for a wider diffusion of other types of reception screens, we must acknowledge that a cathodic ray tube is a vacuum glass bulb, which three electronic guns  (for the color) and a fluorescent screen (phosphorus) on its inner surface, where the image forms its elf through scanning of the electrons. A transformer (high tension) quickens and runs the three beams of particles towards the front of the tube. Their motions are run by deviation coils through which an electric current circulates, producing magnetic fields.

The fields thus produced are more important at the back and on the sides than in front of the screen (1 milliGauss 1,5 - 2 m far in front) ; on the other hand, various frequencies are emitted (Frequencies of horizontal scanning : from 10 to 30 kiloHz = Very Low Frequencies or V.L.F. - frequencies of vertical scanning : from 50 to 75 Hz = Extremely Low Frequencies or E.L.F.), not to speak of those emitted by the alternating current 50 Hertz of the supply of the transformer which produces its own fields, to mention non-ionizing radiations only. The practice of prudent avoidance leads us to advise people to watch TV  some distance  away  (it is necessary, notably, for children who are used to pressing their noses on the TV screen). As to the use to the computer, this practice is more difficult on account of the readability on the screen. Added filters may change certain of the visual conditions, limit static electricity and electric fields, but -by no means- play a part in the various fields previously described.

On the other hand, specific systems might act on these radiations emitted in the neighborhood of cathodic screens (based on "neutrinos" carrying  photons for "Neutral", or solution oxides of rare earths used to produce a counter-phase resonance which would cancel the biological harmfulness of such emissions, such "EMF-BIOSHIELD® from A.NOX® Technology"). Apart from the use of "biological models", classical means of scientific investigation do not yet enable us to ascertain such protective action quite objectively and we must beware of numerous gadgets furthermore marketed which cannot have any neutralizing effect, as regards electromagnetic fields thus produced.

- Extremely Low Frequencies (E.L.F.) and electric currents

Any kind of electric current produces an electric field and a magnetic field. Its intensity is the higher as you stand next to its source ; this field rapidly decreases with the distance ; that is why the concept of "prudent avoidance" is interesting (developed in USA). Sweden is the first country which has adopted this principle of precaution through prudent avoidance to protect populations.

An electric field is produced by the presence of electric charges (electrons) ; it therefore depends on the voltage (lines of transport in 400.000 volts, or of household distribution in 220 volts, for example). The electric field is measured in volts per metre (V/m). The higher the supplying tension of a device is, the more intense is the electric field produced. The wires of a plugged electric appliance produce an electric field even if the appliance is not working, hence the interest of field interrupters. Its intensity may be considerably decreased by elements which can form a screen (trees, buildings...).

A magnetic field is induced by the passage of electric current, that is by the movement of electrons. Consequently, it can only be produced if an appliance is working. The stronger the intensity of the current (expressed in amperes) is, the more important the produced magnetic field will be. Contrary to the electric field no efficient screen (apart from mû-metal) can act as a protection against the magnetic field, so that is goes quite easily through the matter, the various structures of the house, as well as the human body... Its intensity is expressed in Teslas (once in Gauss, this unit is still used : 1 Tesla = 10.000 Gauss), or more often, in fractions of these units : 1 milliGauss (mG) = 0,1 micro Tesla (µT). The ampere is also sometimes used per metre (A/m).

All appliances, equipments and electric wires produce electric and magnetic fields (EMF). Therefore, in our environment, we are all exposed to them. The type of equipment, the distance to the source and the time spent in its neighbourhood are three essential factors which should be taken into account in the evaluation of the exposure to electric  and  magnetic  fields (EMF). It is equally important to keep into account the cumulative effects of the various fields, in the same way as, for example, the possible action of the radioactive descendants of the radon, formed under the influence of electric fields, along the lines of transport of the current, as Prof. Denis Henshaw from the University of Bristol in Great Britain asserts.

The National Council on Radiations Protection and measurements (NCRP), depending on the Environmental Protection Agency (EPA) in the USA, has defined the ALARA concept. (As Low As Reasonably Achievable) in the sanitary field, to try and protect populations from any risks in the future, suggesting a progressive decrease of their exposure to the EMF of their environment. In a preliminary report (NCRP, 1995), the proposed guidelines of security recommend a threshold of exposure fixed to 0,2 µT (micro Tesla) or 2 mG (milliGauss) for ambient magnetic fields in 60 Hertz. This limiting value for pathogenic risks is confirmed by most of the independent recent studies of the International Scientific Community (5 V/m or 10 V/m, according to the authors, for electric fields).

Better prevent than cure

I find it personally important to apply these minima guidelines "A.L.A.R.A." to the quality of life and above all of sleep in habitat. That is why  -for these various electromagnetic fields- I defined an effective "zone of biological neutrality" more comfortable (in bed-rooms in particular). Considering hypersensitive persons particularly, I now advise in this purpose to limit the exposure to less than 0,1 mGauss for magnetic fields (using as a reference the minimum value of the measurements of the ambient magnetic fields noted in Quebec houses by the Institute of Research of Hydro-Quebec, with a variation of 0,01 µT to 1 µT then, that is to say 0,1 mG to 10 mG). Moreover similarly, I suggest less than 1 Volt/m for electric fields with the usual current 50 Hz (in Europe) / 60 Hz (in North America), and a power density inferior to 0,1 µwatt/cm2 for the hyper frequencies of mobile telephones GSM of à 925 megahertz (according to the New-Zealand work of Prof. Neil Cherry in this case).