ROMA – Arpa Piemonte, together with the antiviral research laboratory of San Luigi Gonzaga in Orbassano, has developed after eight months of work a method to certify if there is coronavirus in the air. It is a method, that of the Regional Environmental Protection Agency, which uses machinery used for the purpose and for the first time allows to determine the concentration of Sars-CoV-2 in the “air matrix”.
It is an important patent discovery, given that in the certification of the virus inside the environments – in an office, in a living room, in a classroom, in a train carriage – the next pandemic defense policies can be played with resulting choices.
The multidisciplinary approach that led to the creation of a “reproducible and validable” protocol, as explained by the general manager of Arpa Piemonte, Angelo Robotto, it was possible by passing through three separate research and intervention modes. In the first case, a centrifugal impactor was used capable of accelerating the flow of aspirated air to the speed of sound, thus minimizing losses due to evaporation, maintaining the infectivity and integrity of the viral particles by transferring them directly into a solution of adequate transportation. Then, we went through a low volume sampler to filter the air on filters that guarantee the maximum capture capacity of the viral particles. Finally, a high volume sampler with glass fiber or quartz filters: it is capable of aspirating the entire volume of a room in less than an hour.
The system has already found its first applications: inside and outside hospital departments dedicated to the care of Covid patients, for example, but also in the streets of the center of Turin (Via della Consolata), in private homes. The indications were in some ways surprising. The first results show, in fact, that in the external environment the infected particles are not detectable. In hospitals, and in particular in wards with the presence of patients with high viral loads, the detectable concentrations were very low. The explanation given, in this case, is “the high air exchange rate achieved in the areas”. The windows can be opened in these wards 6-8 times per hour.
Finally, the important concentration found in the checks inside the houses is striking. “Up to 40/50 genomic pairs of the virus per cubic meter of air”, reads the Arpa report. “These values are strongly influenced by the air exchange frequencies and the number of positive subjects present in the homes, as well as by the development of the most common symptoms of the disease such as dry cough”.
The analysis results confirm studies from last spring. “Now we have a solid basis”, says Robotto, “to develop reliable methods to quantify the viral load in the air, allowing, in perspective, to assess the degree of contagion risk in a gym, in a cinema, in a station”.
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