A high-resolution emission inventory for air quality modeling studies in Hanoi, Vietnam in 2017

Abstract:

Vietnam is on a rapid socio-economic development process. Hanoi, the capital city and the political, economic and cultural center of Vietnam, is now facing a deteriorating air environment due to such development. An emission inventory of air pollutants at a spatial resolution of 1km×1km was developed for Hanoi for the year 2017 using a combination of bottom-up and top-down method. The sectors included in the emission inventory were agriculture, residential sector, commercial sector, transport, industry, power plants, solvents and other products use, and gas stations. Power plants were an exception as no power plants are located in Hanoi. The purpose of including emissions from power plants was to evaluate their impact on the air quality in Hanoi using air quality models. The results show that in 2017 total emissions of PM_2.5, SO₂, CO, NO_x, NH₃, CH₄, NMVOC, BC, and OC in Hanoi were 28.17, 37.28, 371.46, 55.86, 20.9, 79.35, 94.88, 2.85, and 6.35 Gg, respectively. Industrial activities were the main source of PM_2.5 by contributing 32.1%, followed by agriculture (28.6%) and transport (26.1%). These were also the main source of SO₂ by contributing 84.4%, followed by transport (13.3%). On the other hand, transport was the main source of NO_x and NMVOC by contributing 70.6% and 46%, respectively. Agriculture dominated the NH₃ emission by contributing 95.9%. In addition, spatial and temporal (monthly, daily, hourly) distributions of emissions were developed which can be used as input for air quality models. Spatially, high emissions of air pollutants were found at the center of Hanoi, highly industrialized areas, and the main roads. The emissions will be useful for air quality modelling studies in Hanoi and will be used to find out the main sources of air pollution in Hanoi with the help of air quality models such as the WRF-CMAQ system.