Reactive nitrogen in atmospheric emission inventories 1Centre for Ecology & Hydrology (CEH), Bush Estate, Penicuik, EH26 0QB, UK
2US Environmental Protection Agency, Atmospheric Modeling Division, 109 T W Alexander Drive, Research Triangle Park, NC 27711, USA
3Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
4The College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China
Received: 26 April 2009 – Published in Atmos. Chem. Phys. Discuss.: 20 May 2009 Abstract. Excess reactive Nitrogen (Nr) has become one of the most pressing
environmental problems leading to air pollution, acidification and
eutrophication of ecosystems, biodiversity impacts, leaching of nitrates
into groundwater and global warming. This paper investigates how current
inventories cover emissions of Nr to the atmosphere in Europe, the
United States of America, and China. The
focus is on anthropogenic sources, assessing the state-of-the-art of
quantifying emissions of Ammonia (NH3), Nitrogen Oxides (NOx) and
Nitrous Oxide (N2O), the different purposes for which inventories are
compiled, and to which extent current inventories meet the needs of
atmospheric dispersion modelling. The paper concludes with a
discussion of uncertainties involved and a brief outlook on emerging trends
in the three regions investigated is conducted.
Revised: 15 September 2009 – Accepted: 18 September 2009 – Published: 15 October 2009
Key issues are substantial differences in the overall magnitude, but as well
in the relative sectoral contribution of emissions in the inventories that
have been assessed. While these can be explained by the use of different
methodologies and underlying data (e.g. emission factors or activity rates),
they may lead to quite different results when using the emission datasets to
model ambient air quality or the deposition with atmospheric dispersion
models. Hence, differences and uncertainties in emission inventories are not
merely of academic interest, but can have direct policy implications when
the development of policy actions is based on these model results.
The level of uncertainty of emission estimates varies greatly between
substances, regions and emission source sectors. This has implications for
the direction of future research needs and indicates how existing gaps
between modelled and measured concentration or deposition rates could be
most efficiently addressed.
The observed current trends in emissions display decreasing NOx
emissions and only slight reductions for NH3 in both Europe and the US.
However, in China projections indicate a steep increase of both.
Citation: Reis, S., Pinder, R. W., Zhang, M., Lijie, G., and Sutton, M. A.: Reactive nitrogen in atmospheric emission inventories, Atmos. Chem. Phys., 9, 7657-7677, doi:10.5194/acp-9-7657-2009, 2009.