[2020 en technos] This aerosol contamination that France cannot see

    [2020 en technos] This aerosol contamination that France cannot see

    By air. Several meters away. By making fun of the hydroalcoholic gel. This is also how the Covid-19 is transmitted. It is more precisely the contamination by aerosol, that is to say a suspension of micro-droplets smaller than the postilions which floats in the air and can wander with the currents to infect people more than ten meters away. .

    If the exact importance of this route of contamination compared to the others remains to be determined, the scientific literature as well as the precedent of SARS-CoV-1 require that aerosol transmission be taken into account in order to fight the pandemic.

    What remains to be done in France, in contrast to Germany and the United States, but also in many other countries as this idea of ​​a possible contamination by the air has struggled to prevail in the face of a medical community largely focused on direct contamination by contact and splashing droplets.

    Aerosols brought to light in May by massive contaminations in slaughterhouses

    Proponents of the aerosol path, often scientists working on air quality, have been struggling since the beginning of the year to convince medical institutions when, at the end of April-beginning of May, a wave of massive contaminations broke out in the slaughterhouses and meat cutting plants.

    First in the United States where these clusters then account for half of the major epidemic foci, then to a lesser extent in Germany and France. Aerosol contamination is essential to explain these cases. But also to explain more generally the apparent predominance of contaminations in closed places and the importance of super-contamination events.

    At the start of the school year, masks are finally essential but not at school where aerosols are worrying … abroad

    The aerosol contamination was finally admitted by the WHO in July, after the mobilization of researchers from around the world. In August, after public places, it is finally in companies that wearing a mask is essential. A key measure to reduce the emission of aerosols, but which is never explained in this way by the government.

    Like Elizabeth Borne declaring in August that in open space the mask is not necessary or Jean-Michel Blanquer estimating that at two meters distance we can remove the mask, the government hides the aerosol contamination at the risk of making the obligation to wear a mask incomprehensible, even at more than the famous 1.5 m. This aerosol route will never be clearly explained by the State thereafter.

    Elsewhere, in Germany and the United States, universities are mobilizing to study the risks of areosol in classrooms and lecture halls, and to protect themselves against them by reducing density and ventilating.

    Against aerosols: CO2 measurement and ventilation. The High Council for Public Health publishes its recommendations

    Many voices, academics, doctors and parents have been calling since the start of the September school year to take into account the aerosol risk in enclosed spaces by renewing the air by ventilating but also by using air purifiers. Measuring the CO2 rate appears to be a key indicator of good air renewal.

    The recommendations of the High Council for Public Health (HCSP) on the adjustment of ventilation systems go in this direction. Fabien Squinazi, medical biologist at HSCP and co-editor of this opinion, provides Industry & Technologies in detail with this aerosol risk. And points out that surgical-type masks only offer very partial protection since they do not filter the smallest droplets at the exit or at the entrance.

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