Regional nitrogen oxides emission trends in East Asia observed from space

Abstract

Due to changing economic activity, emissions of air pollutants in East Asia change rapidly in space and time. Monthly emission estimates of nitrogen oxides derived from satellite observations provide valuable insight in the evolution of anthropogenic activity on a regional scale. We present the first results of a new emission estimation algorithm, specifically designed to use daily satellite observations of column concentrations for fast updates of emissions of short-lived atmospheric constituents on a~mesoscopic scale (~ 0.25° × 0.25°). The algorithm is used to construct a monthly NO_x emission time series for 2007–2011 from tropospheric NO₂ observations of GOME-2 for East Chinese provinces and surrounding countries. The new emission estimates correspond well with the bottom-up inventory of EDGAR v4.2, but are smaller than the inventories of INTEX-B and MEIC. They reveal a strong positive trend during 2007–2011 for almost all Chinese provinces, related to the country's economic development. We find a 41% increment of NO_x emissions in East China during this period, which shows the need to update emission inventories in this region on a regular basis. Negative emission trends are found in Japan and South Korea, which can be attributed to a combined effect of local environmental policy and global economic crises. Analysis of seasonal variation distinguishes between regions with dominant anthropogenic or biogenic emissions. For regions with a mixed anthropogenic and biogenic signature, the opposite seasonality can be used for an estimation of the separate emission contributions. Finally, the non-local concentration/emission relationships calculated by the algorithm are used to quantify the direct effect of regional NO_x emissions on tropospheric NO₂ concentrations outside the region. For regions such as North Korea and Beijing province, a substantial part of the tropospheric NO₂ originates from emissions elsewhere

Monthly top‐down NOx emissions for China (2005–2012): A hybrid inversion method and trend analysis

“…In the first panel, the red dotted line is the hybrid posterior emissions over East China (18–50°N, 102–132°E); the magenta line in the first panel is the bottom‐up anthropogenic emissions from the MEIC inventory plus GEOS‐Chem prior natural emissions; the yellow line is the bottom‐up anthropogenic emissions from Xia et al [] plus GEOS‐Chem prior natural emissions. The cyan dotted line in the first panel is the top‐down estimate for total emissions in East China (18–50°N, 102–132°E) from Mijling et al [].…”

“…These forms of air pollution lead to decreased visibility [ Haagen‐Smit , ], cardiac and respiratory morbidity [ Bhatnagar , ; Ghio et al , ; Nel , ], and acidification and eutrophication of waters when deposited in excess [ Driscoll et al , ; Likens et al , ]. Though NO x emissions in North America [ Kim et al , ; Lamsal et al , ; Russell et al , ; Lu et al , ] and Western Europe [ Castellanos and Boersma , ] have decreased in the past two decades, their emissions in China have increased rapidly due to economic development and urbanization since the turn of the century [ Stavrakou et al , ; Lamsal et al , ; Lin and McElroy , ; Zhao et al , ; Mijling et al , ; Jin and Holloway , ; Krotkov et al , ; Cui et al , ; Duncan et al , ; Xia et al , ].…”

Hybrid Mass Balance/4D‐Var Joint Inversion of NOx and SO2 Emissions in East Asia

“…For instance, the four‐dimensional variational (4D‐Var) method (e.g., Elbern et al, , ; Henze et al, , ) has been compared with the mass balance approach (e.g., Boersma et al, ; Martin, Jacob, Chance, et al, ; Toenges‐Schuller et al, ) in Qu et al (), and a hybrid 4D‐Var/mass balance method has been developed to derive top‐down NO x emissions for China from 2005 to 2012. Extended Kalman filter (e.g., Ding, van der A, et al, ; Mijling et al, ) and ensemble Kalman filter (e.g., Miyazaki et al, ) are employed to estimate multiyear NO x emissions in China. 4D‐Var (e.g., Qu et al, ; Wang et al, ; Xu et al, ), mass balance (e.g., Koukouli et al, ; Lee et al, ), and plume methods (e.g., Fioletov et al, ; McLinden et al, ) have also been applied to derive SO 2 emissions from OMI SO 2 and Moderate Resolution Imaging Spectroradiometer aerosol optical depth (AOD) observations.…”

PAN in the eastern Pacific free troposphere: A satellite view of the sources, seasonality, interannual variability, and timeline for trend detection

“…Mijling et al . [] showed that NO x emissions continued to rise in East China through 2011, though there were reductions in Japan and South Korea. Fischer et al .…”