An air purification assembly comprising: - a chamber comprising an air inlet for the passage of a polluted air, an air outlet for the passage of a purified air and a base provided with means for carrying out a forced air circulation in the chamber, such as a fan, - a plurality of removable cartridges housed in said chamber, said cartridges being adapted to be traversed in parallel by the polluted air circulating in the chamber in order to purify it, each of the cartridges being provided, at the inlet thereof, with an opening and closing mechanism configurable between an open configuration and a closed configuration for respectively allowing the air to circulate or for blocking the circulation of air through the associated cartridge, said air purification assembly further comprising: - a measurement system for measuring parameters representative of the quality of the air to be purified; - control means connected to the measurement system and to the opening and closing mechanism of each of the cartridges, said control means being configured to control the opening and closing mechanisms in order to open and close individually, for example distinctly or in combination, the cartridges so as to adapt the air flow rate depending on the parameters representative of the quality of the air to be purified; wherein said air purification assembly comprises at least one downstream filtration module (9; 10) disposed downstream of the cartridges, in the front of the air circulation inside the assembly, and wherein the downstream filtration module (9; 10) is removable between an active position where it is disposed on the path of the air circulating inside the purification assembly so as to be traversed by this air and an inactive position where it does not ensure the filtration of the air, these active and inactive positions being controlled by the control means depending on at least one parameter representative of the quality of the air to be purified. - a chamber comprising an air inlet for the passage of a polluted air, an air outlet for the passage of a purified air and a base provided with means for carrying out a forced air circulation in the chamber, such as a fan, - a plurality of removable cartridges housed in said chamber, said cartridges being adapted to be traversed in parallel by the polluted air circulating in the chamber in order to purify it, each of the cartridges being provided, at the inlet thereof, with an opening and closing mechanism configurable between an open configuration and a closed configuration for respectively allowing the air to circulate or for blocking the circulation of air through the associated cartridge, said air purification assembly further comprising: - a measurement system for measuring parameters representative of the quality of the air to be purified; - control means connected to the measurement system and to the opening and closing mechanism of each of the cartridges, said control means being configured to control the opening and closing mechanisms in order to open and close individually, for example distinctly or in combination, the cartridges so as to adapt the air flow rate depending on the parameters representative of the quality of the air to be purified; wherein said air purification assembly comprises at least one downstream filtration module (9; 10) disposed downstream of the cartridges, in the front of the air circulation inside the assembly, and wherein the downstream filtration module (9; 10) is removable between an active position where it is disposed on the path of the air circulating inside the purification assembly so as to be traversed by this air and an inactive position where it does not ensure the filtration of the air, these active and inactive positions being controlled by the control means depending on at least one parameter representative of the quality of the air to be purified. - a measurement system for measuring parameters representative of the quality of the air to be purified; - control means connected to the measurement system and to the opening and closing mechanism of each of the cartridges, said control means being configured to control the opening and closing mechanisms in order to open and close individually, for example distinctly or in combination, the cartridges so as to adapt the air flow rate depending on the parameters representative of the quality of the air to be purified;