A recent emission inventory of multiple air pollutant, PM2.5 chemical species and its spatial-temporal characteristics in central China

A high–resolution emission inventory of primary air pollutants of 18 cities in Henan region, as the representative of central plains of China, was developed based on the combination of bottom–up and top-down methods. It was found that the emissions of sulfur dioxide (SO₂), nitrogen oxides (NOₓ), carbon monoxide (CO), particulate matter with an aerodynamic diameter of 10 mm or less (PM₁₀), particulate matter with an aerodynamic diameter of 2.5 mm or less (PM₂.₅), Volatile Organic Compounds (VOCs) and ammonia (NH₃) in 2016 were 780.4, 1682.9, 7152.8, 1440.3, 757.2, 1110.7, and 982.0 Gg, respectively. The emissions of the three major PM₂.₅ species, namely, Organic carbon (OC), Elemental carbon (EC), and sulfate (SO42−), were 161.2, 83.1, and 64.6 Gg, respectively. Stationary combustion was the largest contributor to SO₂, NOₓ, CO, and PM₂.₅ emissions with 71.6%, 49.0%, 34.1%, and 24.7% contributions, respectively. Dust was the dominant source of PM₁₀ emissions (42.4%), whereas industrial process was the largest contributor to VOCs emission (34.8%). Agricultural source contributed 87.7% of NH₃ emission. The emissions were mainly distributed over the northwest and central part of Henan, and cities of Anyang, Zhengzhou, Luoyang, Pingdingshan, and Jiaozuo were the major contributors. Large NH₃ emissions occurred during May to September, and high emissions of other pollutants were found from October to January. According to the Gini coefficients of per capital Gross Domestic Product (GDP) distribution among multiple air pollutants, the SO₂ and NH₃ emissions had high regional disparity, and the cities of Anyang and Zhengzhou had a high economic–environment inequity. Furthermore, this results were evaluated by comparing with other studies and the trend of spatiotemporal observed ambient concentration, which proves that the results are reliable. This work may benefit the government to further understand current local emission characteristics and formulation of targeted air pollution control measures.