CREATE TABLE table_name_39 (performance VARCHAR(255), class VARCHAR(255), test_standard VARCHAR(255), particulate_size_approaching_100_percentage_retention VARCHAR(255))
Which  Performance has a Test Standard of bs en779, and a Particulate size approaching 100% retention of >2µm, and a Class of f6?
    
SQL: SELECT performance FROM table_name_39 WHERE test_standard = "bs en779" AND particulate_size_approaching_100_percentage_retention = ">2µm" AND class = "f6"