41 Importance of Inventory Representativeness …
265
et al. [9] show mean 48 h observed and predicted NO 2 time series for eastern Canada
(EC) and the eastern U.S. (EUS) for both the summer 2016 and winter 2017 periods
and O 3 and PM 2.5 time series for summer 2016. NO 2 concentration bias is reduced
over the EUS for both periods, suggesting that the new NO x emissions from the 2017
projected U.S. NEI are more representative for 2017 than the 2011 NEI emissions,
consistent with Fig. 41.1. Unlike the winter period shown in Fig. 41.4b, O 3 levels
over the EUS are reduced in summer 2017 due to decreased production from lower
NO x emissions [7].
41.4 Conclusion
To make AQ forecasts we should ideally use current emissions, but national emissions
inventories are generally retrospective. This becomes an issue when emissions are
changing significantly from year to year, as has been the case in North America for
the past decade or more.
Projected emissions inventories may be less accurate than actual inventories for
the same base year, but they have the advantage of being available years sooner
and they may also be quite accurate if projected emissions changes are largely the
result of known emission control legislation. This study shows one example where a
projected 2017 emissions inventory gave more representative estimates of emissions
levels in 2016 and 2017 than did a retrospective inventory for 2011.
A new version of the ECCC forecast system that uses these updated input emissions files was accepted for operational implementation in mid 2018 [8].
References
1. AQMAS, Documentation for SMOKE-Ready 2013 and 2025 Air Pollutant Emission Inventory
(APEI) Package version 1. Report number AQSC-17-003, Air Quality Modelling Applications
Section, Environment and Climate Change Canada, Montreal, Quebec, April, 15 pp. (2017)
2. ECCC (2018), http://ec.gc.ca/indicateurs-indicators/default.asp?lang=en&n=E79F4C12-1
3. M. Moran, Q. Zheng, J. Zhang, R. Pavlovic, RAQDPS Version 013: upgrades to the CMC
Operational Regional Air Quality Deterministic Prediction System released in June 2015.
Canadian Meteorological Centre Technical Note, Montreal, November, 54 pp. (2015), http://
collaboration.cmc.ec.gc.ca/cmc/cmoi/product_guide/docs/lib/op_systems/doc_opchanges/
Technical_Note_GEM-MACH10_v1.5.3+SET2.1.1_Emissions_9Nov2015.pdf
4. M.D. Moran, Q. Zheng, J. Zhang, R. Pavlovic, M. Sassi, Impact on recent North American AQ
forecasts of replacing a retrospective U.S. emissions inventory with a projected inventory, in
16th CMAS Conference, 23–25 October 2017, Chapel Hill, North Carolina (2017), https://www.
cmascenter.org/conference//2017/slides/moran_impact_recent_2017.pptx
265
et al. [9] show mean 48 h observed and predicted NO 2 time series for eastern Canada
(EC) and the eastern U.S. (EUS) for both the summer 2016 and winter 2017 periods
and O 3 and PM 2.5 time series for summer 2016. NO 2 concentration bias is reduced
over the EUS for both periods, suggesting that the new NO x emissions from the 2017
projected U.S. NEI are more representative for 2017 than the 2011 NEI emissions,
consistent with Fig. 41.1. Unlike the winter period shown in Fig. 41.4b, O 3 levels
over the EUS are reduced in summer 2017 due to decreased production from lower
NO x emissions [7].
41.4 Conclusion
To make AQ forecasts we should ideally use current emissions, but national emissions
inventories are generally retrospective. This becomes an issue when emissions are
changing significantly from year to year, as has been the case in North America for
the past decade or more.
Projected emissions inventories may be less accurate than actual inventories for
the same base year, but they have the advantage of being available years sooner
and they may also be quite accurate if projected emissions changes are largely the
result of known emission control legislation. This study shows one example where a
projected 2017 emissions inventory gave more representative estimates of emissions
levels in 2016 and 2017 than did a retrospective inventory for 2011.
A new version of the ECCC forecast system that uses these updated input emissions files was accepted for operational implementation in mid 2018 [8].
References
1. AQMAS, Documentation for SMOKE-Ready 2013 and 2025 Air Pollutant Emission Inventory
(APEI) Package version 1. Report number AQSC-17-003, Air Quality Modelling Applications
Section, Environment and Climate Change Canada, Montreal, Quebec, April, 15 pp. (2017)
2. ECCC (2018), http://ec.gc.ca/indicateurs-indicators/default.asp?lang=en&n=E79F4C12-1
3. M. Moran, Q. Zheng, J. Zhang, R. Pavlovic, RAQDPS Version 013: upgrades to the CMC
Operational Regional Air Quality Deterministic Prediction System released in June 2015.
Canadian Meteorological Centre Technical Note, Montreal, November, 54 pp. (2015), http://
collaboration.cmc.ec.gc.ca/cmc/cmoi/product_guide/docs/lib/op_systems/doc_opchanges/
Technical_Note_GEM-MACH10_v1.5.3+SET2.1.1_Emissions_9Nov2015.pdf
4. M.D. Moran, Q. Zheng, J. Zhang, R. Pavlovic, M. Sassi, Impact on recent North American AQ
forecasts of replacing a retrospective U.S. emissions inventory with a projected inventory, in
16th CMAS Conference, 23–25 October 2017, Chapel Hill, North Carolina (2017), https://www.
cmascenter.org/conference//2017/slides/moran_impact_recent_2017.pptx