Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_44091 ( "Usage" text, "Class" text, "Performance" text, "Performance test" text, "Particulate size approaching 100% retention" text, "Test Standard" text )

### Question ###
Which Performance has a Test Standard of bs en779, and a Particulate size approaching 100% retention of >2 m, and a Class of f6?

### Accurate SQL ###

SELECT "Performance" FROM table_44091 WHERE "Test Standard" = 'bs en779' AND "Particulate size approaching 100% retention" = '>2µm' AND "Class" = 'f6'