Abstract

Carbon dioxide (CO2) is one of the most important greenhouse gases and atmospheric CO2 concentrations have been recorded increasing. Floating chamber associated with Non-Dispersive Infrared (NDIR) technique as Licor-820 has been used for measuring the CO2 flux F(CO2) (mmol m-2 h-1) that emitted from the water surface on the various canals of Ho Chi Minh City. The highest values at 3 sites: CH – Kenh Đoi, DBP – Kenh Nhieu Loc – Thi Nghe and CD – Rach Cau Son ranged from 35 to 186 mmol m-2 h-1 while much higher at OB site – Rach Ong Lon from 120–474 mmol m-2h-1. Climate characteristics also greatly affect the CO2 emissions in natural waterways with low F(CO2) values in dry season – the highest value fluctuated between 35 and 181 mmol m-2 h-1 while in the rainy season the highest F(CO2) value was 446 mmol m-2 h-1 for OB site and ranged from 65 to 186 mmol m-2 h-1 for 3 other sites CH , DBP and CD. Pollution of waterways also affected on the CO2 emissions.