Between 2000 and 2016, concentrations of nitrogen dioxide in the city fell by 43 per cent, those of carbon monoxide by 53 per cent, sulfur dioxide by 81 per cent, hydrogen sulphide by 75 per cent, nitrogen oxide by 77 per cent and benzene by 90 per cent.
ລະຫວ່າງ 2000 ແລະ 2016, ຄວາມເຂັ້ມຂົ້ນຂອງທາດໄນໂຕຣເຈນອອກໄຊໃນເມືອງໄດ້ຫຼຸດລົງໂດຍ 43 ເປີເຊັນ, ທາດອາຍພິດຄາບອນໄດອອກໄຊທ໌ໂດຍ 53 ເປີເຊັນ, sulfur dioxide ໂດຍ 81 ເປີເຊັນ, hydrogen sulphide ໂດຍ 75 ເປີເຊັນ, ໄນໂຕຣເຈນຜຸພັງໂດຍ 77 ເປີເຊັນແລະ benzene ໂດຍ 90 ເປີເຊັນ.