A.≤6.0(一級(jí)質(zhì)量標(biāo)準(zhǔn)) B.≤3.0(一級(jí)質(zhì)量標(biāo)準(zhǔn)) C.≤18.0(二級(jí)質(zhì)量標(biāo)準(zhǔn)) D.≤16.0(二級(jí)質(zhì)量標(biāo)準(zhǔn))