2013-12-13: Regional nitrogen oxides emission trends in East Asia observed from space

Due to changing economic activity, emissions of air pollutants in East Asia are changing rapidly in space and time. Monthly emission estimates of nitrogen oxides (NOx) derived from satellite observations provide valuable insight into the evolution of human activity on a regional scale.

We published the first results of a new emission estimation algorithm, specifically designed to use daily satellite observations of short-lived atmospheric constituents such as NO2 to update emission inventories. The algorithm is used to construct a monthly NOx emission time series for the period 2007-2011 from tropospheric NO2 observations of GOME-2 for East Chinese provinces and surrounding countries. A strong positive trend is found during 2007-2011 for almost all Chinese provinces, related to the country's economic development. We found a 41% increment of NOx 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 due to their opposite seasonality. The algorithm also provides non-local concentration/emission relationships which were used to show that for regions such as North Korea and the Beijing municipality a substantial part of the tropospheric NO2 originates from emissions elsewhere.

The full article can be found here.

Emission changes in Chinese provinces and surrounding countries derived from space observations during 2007-2011. (a) Total NOx emissions in 2007 per region. (b) Emissions per unit area per region. (c) Annual trends in total NOx emission per region for the 20072011 period. (d) Relative trends for regional NOx emissions.