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_44093 ( "Usage" text, "Class" text, "Performance" text, "Performance test" text, "Particulate size approaching 100% retention" text, "Test Standard" text )

### Question ###
Which Particulate size approaching 100% retention has a Usage of semi hepa and a Class of h12?

### Accurate SQL ###

SELECT "Particulate size approaching 100% retention" FROM table_44093 WHERE "Usage" = 'semi hepa' AND "Class" = 'h12'