An air passage device for the ventilation of air in closed environments, comprising: - a first grid element extending mainly on a first imaginary plane (A) and which has a first thickness (L1) along a first air passage direction (Z-Z) perpendicular to said first imaginary plane (A), wherein said first grid element comprises a first grid body in which first openings are obtained, each extending respectively for the entire first thickness (L1) with a first opening height (H1), along main opening axes (C-C) which are substantially parallel respectively to the first air passage direction (Z-Z), wherein said first openings are delimited by first side walls having a first diffusive reflecting inner surface ; - a second grid element extending on a second imaginary plane (B) and which has a second thickness (L2) along a second air passage direction (Z'-Z') which is perpendicular to said second imaginary plane (B), wherein said second grid element comprises a second grid body in which second openings are obtained each extending respectively for the entire second thickness (L2) with a second opening height (H2), along second main opening axes (C'-C') which are substantially parallel respectively to the second air passage direction (Z'-Z'), wherein said second openings are delimited by second side walls having a second diffusive reflecting inner surface ; - a support frame which supports and connects said first grid element and said second grid element , the air passage device being configured so that the first grid element and the second grid element are crossable in series by air, wherein the first imaginary plane (A) and the second imaginary plane (B) are mutually incident with an inclination angle (α) which is a function of said first and second thicknesses (L1, L2) and of said first and second opening heights (H1, H2), so that at least one portion of a light ray entering said openings is absorbed by the diffusive reflecting inner surface of at least one of said openings . - a first grid element extending mainly on a first imaginary plane (A) and which has a first thickness (L1) along a first air passage direction (Z-Z) perpendicular to said first imaginary plane (A), wherein said first grid element comprises a first grid body in which first openings are obtained, each extending respectively for the entire first thickness (L1) with a first opening height (H1), along main opening axes (C-C) which are substantially parallel respectively to the first air passage direction (Z-Z), wherein said first openings are delimited by first side walls having a first diffusive reflecting inner surface ; - a second grid element extending on a second imaginary plane (B) and which has a second thickness (L2) along a second air passage direction (Z'-Z') which is perpendicular to said second imaginary plane (B), wherein said second grid element comprises a second grid body in which second openings are obtained each extending respectively for the entire second thickness (L2) with a second opening height (H2), along second main opening axes (C'-C') which are substantially parallel respectively to the second air passage direction (Z'-Z'), wherein said second openings are delimited by second side walls having a second diffusive reflecting inner surface ; - a support frame which supports and connects said first grid element and said second grid element , the air passage device being configured so that the first grid element and the second grid element are crossable in series by air, wherein the first imaginary plane (A) and the second imaginary plane (B) are mutually incident with an inclination angle (α) which is a function of said first and second thicknesses (L1, L2) and of said first and second opening heights (H1, H2), so that at least one portion of a light ray entering said openings is absorbed by the diffusive reflecting inner surface of at least one of said openings . <EOS>