SPATIAL CONSIDERATIONS Tim Oxley & Helen ApSimon UK National Focal Centre for Integrated Assessment Imperial College London
AIM: Compatibility national scale (UKIAM) and European scale RAINS-> nesting • Some issues target setting/gap closure MTFR/CLE primary PM
Different approaches to target setting ? Dependence on critical loads of new approach? NB Base year data and critical loads are verifiable Need to examine assumptions in modelling CLE and MTFR & using for target setting carefully.
Case 1 Case 2 Base year CLE 2020 New IIASA targets MTFR Old gap closure Critical load deposition
Change in national emissions Change in conc./deposition S-R matrix for combined sources each country RAINS UKIAM Distinguish change in emission for different sources S-R matrix & abatement cost :-Source 1 Source 2… etc
MAP SHOWS % REDUCTION IN REDUCED NITROGEN DEP AT MTFR FOR NH3. NB Different types of farming in different areas spatially varying applicability of measures Local cost curves in UKIAM
PM2.5 due to UK sources Advantages combining primary and secondary- but primary very different characteristics and source dependence Aim to reduce health risks of population-> population weighted concentrations
Local, mid and far range contributions to population exposure from primary PM sources Not only important how much emissions are cut but also WHICH emissions
EMEP estimates- source apportionment for PM2.5 concs-> some countries ~50% imported For population exposure, correlation between urban populations and urban enhancement increases role of national sources. e.g. country of 15 M people with average background due to own sources of 0.5 mg/m3, and same 0.5 mg/m3from imported sources PLUS 4 M people in urban concns enhanced by 3 mg/m3 Imported contribn = 7.5 National contribn = 7.5 +12= 19.5 ~ 72% of total NB Also imported contribn. Is mainly from neighbouring countries and seas ? EMEP overestimate because artificial attribution for grid-squares across borders
CONCLUSION As well as emission ceilings for primary PM2.5 need to ensure effective reduction in “population exposure” ( including own and neighbouring countries where relevant). ? Ancillary targets ?role of ships in ports ----------------------------------------------------------- Also need to consider target setting overall very carefully- e.g. relation to critical loads, CLE and MTFR.