JRC-AL – Expert Meeting on Cat.4D reporting – 21/ Indirect emissions of N 2 O resulting from energy-related emissions of NO x Adrian Leip Joint Research Centre

JRC-AL – Expert Meeting on Cat.4D reporting – 21/ Nitrogen oxides are indirect greenhouse gases. They have been the target of environmental policies for their role in forming ozone (O3), as well for their direct acidification effect. (IPCC, 2000)

Indirect N 2 O emissions from NOx (Gg N 2 O-N) [1] [1] ATBEDKFIFRDEGRIEITLUNLPTESSEUK [1][1] The emissions of NO x are reported on a full molecular basis assuming that all NO x emissions are emitted as NO 2 (IPCC 1997, page 1.37). Thus, the indirect N 2 O emissions can be calculated by applying the default N 2 O emission factor of 1% to the amount of nitrogen emitted as NO x (converting factor: 14/46) SIGNIFICANCE Increase of total N 2 O emissions ATBEDKFIFRDEGRIEITLUNLPTESSEUK 5%3%4%5%3%4%3%2%4%26%4%7%10%4%6% Increase of total GHG emissions and removals ATBEDKFIFRDEGRIEITLUNLPTESSEUK 0.4%0.3%0.5% 0.4%0.2%0.4%0.3%0.4%0.2%0.3%0.5%0.8% 0.4%

JRC-AL – Expert Meeting on Cat.4D reporting – 21/ CONCLUSIONS For N 2 O emissions, energy-related indirect emissions of N 2 O are a significant contributor of 2% - 26% Energy-related indirect emissions of N2O remain <1% of total greenhouse gas emissions and removals.

JRC-AL – Expert Meeting on Cat.4D reporting – 21/ RECOMMENDATIONS Energy-related emissions of NO x are leading to N 2 O emissions further down in the nitrogen cascade. They can significantly contribute to total anthropogenic N 2 O emissions. Considering these emissions in the guidelines would ensure methodological consistency across the sectors.

JRC-AL – Expert Meeting on Cat.4D reporting – 21/ THANK YOU FOR YOUR ATTENTION !