21 July 2020 – Niigata, Japan

EANET’s fellowship program aims at funding researchers from EANET participating countries to carry out research pertaining to acid deposition at the Network Center in Japan. Cuihong Chen from China was awarded the EANET fellowship for 2016. Chen studied the comparison of observed and modeled nitrogen dioxide (NO₂) from 2013 to 2015, during summer, accounting sensitivity of meteorological conditions, and oxides of nitrogen (NO_x) emission constraints.

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Identifying NO_x Emission Sources to Minimize Emissions

NO_x is an important trace gas in the atmosphere, emitted mainly from anthropogenic sources, such as the combustion of fossil fuels. It plays a key role in atmospheric chemistry by involving in the formation of ozone and secondary particulate matter. Over the past several years, NO_x emissions in China have been increasing rapidly and are resulting in serious atmospheric pollution problems, such as acidic rain, atmospheric haze, and high ozone concentration. This in turn causing harm to human health, environment, and ecosystem. Therefore, identifying NO_x emission sources and efforts to minimize the emissions are necessary. Chen’s research findings provided a good insight into the relationship between satellite observation and modeling of NO₂.

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Meteorological  and NO_x Emissions’ Impacts on NO₂

For the study, Chen used NASA’s satellite data and chemical transport models. She found a good correlation (slope 1.15 and a correlation coefficient of 0.79) between satellite NO₂ and Modeled NO_2. The study reported an increase in tropospheric NO₂ by 4.26% in 2014 compared to that of 2013. The impacts of meteorological conditions and NO_x emissions on the increase of tropospheric NO₂ in 2014 were 2.95% and 1.31%, respectively. The meteorological fields contributed a 3.57% increase in tropospheric NO₂ in 2015.

The study concluded that NO_X emission increased in 2014 and decreased in 2015 during the summer, compared to the level of 2013. The reduction of NO₂ in 2015 was mainly due to the decline of NO_X emissions in China because of the implementation of emission reduction and control measures. The researcher suggested that uncertainty in satellite data and model simulation are needed to be reduced by the development of a non-linear relationship approach in future studies.

The authors acknowledged the Network Center for the Acid Deposition Monitoring Network in East Asia (EANET) and the Asia Center for Air Pollution Research (ACAP) for financial support and observation data.

Read the full article by Chen et al. in the EANET Science Bulletin Volume 5.

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Photo credits: Shanghai by Derek Lee, free of copyright license.

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