2024-03-13 10:30:16
The announcement of the installation on the Athletes’ Village square for the Paris 2024 Olympic Games of street furniture supposed to offer a real “clean air shower” to athletes has sparked numerous reactions, often marked by doubt and incomprehension… Will these devices keep their promises? And what regarding indoor air? Here are some answers.
« Ridicule », « useless », « grotesque »… The harsh criticisms and other cookie-cutter formulas were quick to flourish on social networks following the announcement, last February, of the commissioning in the heart of the Athletes’ Village of the Paris 2024 Olympic Games, of a series of devices intended to rid the outside air of a large part of the fine particles which pollute it : les Aerophiltres. Many Internet users have thus questioned the legitimacy of such an installation, but also – and above all – to immediately deny its effectiveness, calling for many to plant trees rather than relying on what is available. appears in their eyes to yet another techno-solutionist approach… If skepticism is, without a doubt, a healthy and legitimate reaction to the tempting promises of the project, it is perhaps appropriate, however, to look a little more closely details on how the device works.
Patented technology
Beneath their false appearance of flying saucers, these five giant shade houses measuring 4.6 to 5.6 meters in height and 6 meters in diameter hide patented technology – the result of a decade of research and two years of development – embodied by a device: the Para-PM. Developed by the company Aerophile, known in particular for its tethered balloons, the system is capable, according to its designers, of capturing on a large scale the fine particles which pollute the air. How ? Thanks to an innovative electrostatic filter, which the co-founder of Aerophile, Jérôme Giacomoni, described to us last November: “ Theyis regarding‘a three-stage electrostatic filter, which is patented. The system begins by ionizing the polluting particles, which are then collected with a very intense electric field. We have also added a third floor, an innovation covered by our patent. It allowsdrastically increase theefficiency of the system. Electrostatic filters have existed for decades, but the device we invented is particularly suitable for treating air pollution.‘ambiant air. »
Aerophile says thus having obtained, as part of a test campaign carried out in a Parisian schoolyard, particularly convincing results, with a capture of no less than 95% (by mass) of PM2.5 and 10. A figure based on numerical simulations, but also on field measurements presented in August 2023 by Aerophile. « Six pollution sensors Pollutrack were installed by an external laboratory, in the school, to monitor the PM2.5 concentration live on the street side, to know the local ambient pollution, and in the yard to measure theeffectiveness of the device “, explains the group, which thus indicates that “ during the first period of this experiment[1] […] the sensors made it possible to measure […] a rate of depollution of fine particles to a level of at least 95% at the outlet of all devices ».
A first phase followed by a second period of experimentation, planned to extend until April 2024, with the analysis of sensor measurements by an independent laboratory, mandated by the town hall of 9e District of Paris.
The opportunity for a new full-scale experiment
If the impartiality of the first results displayed can therefore hardly be called into question, the question of the transposability of these results remains legitimate, especially since the configuration of the experimental site turns out to be particular, as the group notes. Aerophile himself: “ an open-air space of 330 m2 surrounded by 12 m high walls “. A situation naturally conducive to “ the canyon effect » which, if it normally promotes the accumulation of pollutants, might also in this case, conversely, have a positive influence on the results obtained in terms of depollution, since it promotes looped air circulation closed, by a bell effect, thus slowing down the arrival of new polluting particles…
Doubt as to the real effectiveness of the five filtering shades installed in the heart of the Athletes’ Village is therefore still allowed. The fact remains that the operation is intended, precisely, to be a new opportunity to test the solution in another framework, and on another scale. “To precisely measure its effectiveness over the entire area, a protocol is established by AirParif[2] and will be implemented soon »reveals the Aerophile group.
Whatever the results of this new full-scale experiment, another question remains unanswered: why prefer these potential “pure air showers” to a solution that is at least proven and above all naturally available: the tree? To try to provide the beginnings of an answer, let’s launch into a little “ladle” calculation…
To clean the air, might as well plant trees? Not that easy…
Let us take as basic elements the results of a modeling work carried out by British researchers, published in 2009 in the journal Environmental Pollution. In this study, scientists estimate the capacity for capturing fine particles (PM10) of an area located to the east of London, virtually vegetated with 25% trees and 75% grassland. This, with average annual PM10 concentration values of the order of 22.9 to 25.4 μg per m³ of air, depending on the points in the study area.
If we stick, on the other hand, to the first efficiency results of Para-PM – 95% – as well as the air treatment capacities advanced by Aerophile for its five shade houses in the Athletes’ Village – 108,000 m3 per hour – and combine them with an arbitrary value[3] particle concentration of 23 μg per m3we arrive at a potential particle capture by Aerophiltres of the order of 0.02 tonnes per year[4]. That is as much as 2.2 ha of vegetated urban surface, as defined by British researchers. And this, on an area, this time, of a few tens of square meters, and at the cost of an electrical power drawn of around 5 kW…
Provided that the actual performance of the installation proves to be up to the results obtained in the first field tests carried out by Aerophile, the effectiveness of the solution might therefore prove to be immeasurably greater – if we It concerns the sole question of fine particle pollution – that of the planting of trees. Especially since the effect of Aerophiltres does not stop at PM10 and 2.5 alone: thanks to the addition of a catalyst, they might also make it possible, according to their designers, to reduce part of the pollution with ozone. See you in a few months to find out for sure.
At the Athletes’ Village, indoor air is also treated
Apart from these “pure air showers” which athletes will be able to benefit from outside their resort, an indoor air treatment system for accommodation has also been put in place. It is, in this case, filtering air inlets called EHT2 EFT2 developed by the specialist in ventilation and air treatment equipment Aldes based on technology developed by the company Teqoya: e-filtration. “ This process consists of electrostatically charging the particles, then, secondly, trapping these particles in a system of polarized plates. Electrostatically charged particles are thus deflected by electrostatic forces towards theone of the two plates, the one which has a potential opposite to their charge », Pierre Guitton, co-founder of Teqoya, explained to us in March 2023.
A technology whose performance is now clearly established, as Teqoya emphasizes on its website: “ Its performance is tested under the same conditions as the NF EN ISO 16890 standard: filtration of 90% of particles larger than 10 µm, 80% of particles larger than 2.5 µm and 77% of particles larger than 1 µm “. As evidence a set of tests and certificates made public by the company on its website.
[1] Which took place from June 15 to August 13, 2023.
[2] Air quality observatory in Île-de-France, member of the AASQA network (approved air quality monitoring associations).
[3] Value which corresponds to the low value of the average annual concentrations taken into account in their study area by British researchers.
[4] 95% of 23 μg per m3 give a capture of 21.85 μg of particles per m3 of treated air. Multiplied by the approximately 108,000 m3/h mixed by the five Aerophiltres, we obtain a capture of approximately 2.36 grams of particles per hour, or approximately 20,687 grams in one year, or 0.02 tonnes.
1710643989
#Paris #athletes #breathe #healthier #air #heart #Olympic #Village
