Apparatus for contrasting bacterial and/or viral contamination in a closed environment, comprising: - a wall configured to be incorporated in a ceiling or to constitute a ceiling of an environment which may be occupied by people, so as to delimit said environment; said wall having a plurality of operating portions which are open or permeable to an airflow to allow air to pass through said operating portions; - suction means connected to said wall to suck air through said operating portions; wherein said suction means are configured to form, following their actuation, an updraft directed towards said wall having a flow rate which, expressed in m 3 /h per unit of surface of the floor area of said environment expressed in m 2, is between 60 and 3000; wherein said suction means and/or said operating portions are configured to define, for each operating portion, an operating direction along which air is sucked through said operating portion following an actuation of said suction means; wherein the operating directions of each operating portion are mutually parallel and parallel to a main direction of said air stream formed by said updraft; wherein said suction means and/or said operating portions are configured such that following an actuation of said suction means, the air forming said air stream has substantially uniform directions and speeds in at least one plane perpendicular to said main direction; wherein said suction means define a suction face and a delivery face of said wall; said apparatus comprising: - a casing which, in cooperation with said delivery face, delimits a treatment compartment; said suction means being configured to introduce, into said treatment compartment, air sucked in through said operating portions; - sanitizing means which are placed in said treatment compartment or in fluidic communication with said treatment compartment and are configured to reduce a bacterial and/or viral load present in the air which faces and/or laps said sanitizing means; wherein said sanitizing means are configured to irradiate the interior of said treatment compartment with a UV-C radiation having an irradiation per unit of time which is not less than 1300 microW/cm 2; wherein the treatment compartment and the sanitizing means are chosen to result in an irradiation time of at least 0.5 s. - a wall configured to be incorporated in a ceiling or to constitute a ceiling of an environment which may be occupied by people, so as to delimit said environment; said wall having a plurality of operating portions which are open or permeable to an airflow to allow air to pass through said operating portions; - suction means connected to said wall to suck air through said operating portions; wherein said suction means are configured to form, following their actuation, an updraft directed towards said wall having a flow rate which, expressed in m 3 /h per unit of surface of the floor area of said environment expressed in m 2, is between 60 and 3000; wherein said suction means and/or said operating portions are configured to define, for each operating portion, an operating direction along which air is sucked through said operating portion following an actuation of said suction means; wherein the operating directions of each operating portion are mutually parallel and parallel to a main direction of said air stream formed by said updraft; wherein said suction means and/or said operating portions are configured such that following an actuation of said suction means, the air forming said air stream has substantially uniform directions and speeds in at least one plane perpendicular to said main direction; wherein said suction means define a suction face and a delivery face of said wall; said apparatus comprising: - a casing which, in cooperation with said delivery face, delimits a treatment compartment; said suction means being configured to introduce, into said treatment compartment, air sucked in through said operating portions; - sanitizing means which are placed in said treatment compartment or in fluidic communication with said treatment compartment and are configured to reduce a bacterial and/or viral load present in the air which faces and/or laps said sanitizing means; - a casing which, in cooperation with said delivery face, delimits a treatment compartment; said suction means being configured to introduce, into said treatment compartment, air sucked in through said operating portions; - sanitizing means which are placed in said treatment compartment or in fluidic communication with said treatment compartment and are configured to reduce a bacterial and/or viral load present in the air which faces and/or laps said sanitizing means; wherein said sanitizing means are configured to irradiate the interior of said treatment compartment with a UV-C radiation having an irradiation per unit of time which is not less than 1300 microW/cm 2; wherein the treatment compartment and the sanitizing means are chosen to result in an irradiation time of at least 0.5 s.