economic valuation of environmental effects of nox-emissions from air traffic at different altitudes

1. Economic valuation of environmental effects of NOx-emissions from air traffic at different altitudes  Robert Bergström and Joakim Langner SMHI – The Swedish Meteorological and Hydrological Institute Robert.Bergstrom@smhi.se Lena Nerhagen VTI – The Swedish National Road and Transport Research Institute Bertil Forsberg Umeå University

3. SMHI – Aviation The Environmental & Safety Service Department Forecasting service for the aviation sector Climate and Environmental Studies of Airports [Hans.Backstrom@smhi.se] The Research Department Regional and continental scale modelling of air traffic emission impacts [Robert.Bergstrom@smhi.se]

4. Background Swedish transport policy implies that the external marginal costs of transport should be the basis for taxes and charges The external marginal costs include the cost of the wear and tear of infrastructure, environment, noise, accidents and congestion Environmental costs may, e.g., include damages to natural ecosystems, agricultural and forest production, human health and changes in climate

5. Background Air traffic emission charges usually only consider local air quality issues and take into account emissions in the Landing and Take-Off (LTO) cycle Only part of the aircraft emissions are released during the LTO-cycle (for Swedish air space the non-LTO emissions of NOx are about 5 times larger than the LTO-emissions)

6. Background If the contributions from non-LTO emissions to environmental problems are significant it is reasonable to introduce NOx emission charges also for these emissions The Swedish Civil Aviation Authority have therefore initiated studies aimed at providing the information needed for economic valuation of the environmental effects caused by aircraft emissions at different altitudes in Sweden

7. The Impact Pathway Method The Impact Pathway (IP) Method is a bottom-up approach used for assessment of external impacts and associated costs resulting from energy production or transport The IP Method was developed within the ExternE research projects An impact pathway is the sequence of events linking a burden or emission to an impact and subsequent valuation

8. Schematic view of the Impact Pathway approach

11. Results – Summary Marginal costs for NOx emissions from aviation in Swedish air space are estimated to be higher for LTO emissions than for non-LTO emissions LTO-emissions: ca 1.89 EUR (17 SEK) / kg NOx Non-LTO-emissions: ca 0.91 EUR (8 SEK) / kg NOx The corresponding total NOx emission costs from emissions in Swedish air space are higher for non-LTO emissions than for LTO emissions LTO-emissions: ca 1.7 million EUR Non-LTO-emissions: ca 4.4 million EUR Using ExternE methodology lead to higher costs LTO-emissions: ca 7.2 million EUR Non-LTO-emissions: ca 13 million EUR

12. Results – Summary The costs due to acidification and eutrophication of natural ecosystems dominate but they are very uncertain. If ecosystem effects are excluded the marginal costs become almost the same for LTO and non-LTO emissions of NOx. LTO-emissions: 0.63-0.77 EUR / kg NOx Non-LTO-emissions: 0.56-0.74 EUR / kg NOx Costs due to crop loss and effects on agricultural soils were estimated to be much smaller than costs due to health effects.

13. Outline Environmental effects studied Models used Emissions scenarios The results in more detail

14. Considered effects in the valuation Impact on human health from surface ozone and particulate matter (PM) Impact on agricultural crops from surface ozone Impact on agricultural soils and natural ecosystems from acidifying and eutrophying deposition of oxidised nitrogen

15. Some excluded effects in the valuation Impacts on climate Impact on forests and natural vegetation from surface ozone Impact on building materials through corrosion and soiling and impacts on crops through SO2

17. Modelling domains

18. Models – emission data Detailed emission data for traffic in Swedish air space were taken from the project:Input data for model studies of environmental effects of NOx-emissions from air traffic at different altitudes Commissioned by:The Swedish Civil Aviation Administration, Luftfart och samhälle Joakim Langner and Robert Bergström SMHI Jana Moldanová IVL, (The Swedish Environmental Institute) Anette Näs och Anders Hasselrot FOI (The Swedish Defence Research Agency)

19. Emission data for traffic in Swedish air space Emissions of nitrogen oxides (NOx), carbon monoxide (CO), Volatile Organic Compunds (VOC), and sulphur dioxide (SO2) were derived, for Swedish air space, for the year 2002 Horizontal resolution 20 km Vertical resolution 500m Information about fuel consumption was also derived with the same geographical resolution

20. Emission data for traffic in Swedish air space LTO-emissions – based on official statistics from LFV 19 airports, run by LFV, included non-LTO-emissions: Domestic traffic International flights Overflights Temporal emission variations based on traffic statistics from Arlanda airport 2002 Monthly variation Weekday variation Diurnal variation

21.

22. Vertical distribution of total emissions in Swedish airspace 2002

23. Global emission data from ANCAT/EC2 and DLR

24. Emission data

25. Impact of NOx-emissions from air traffic in Swedish air spaceScenario-calculations

26. Model results Model calculations have been performed for one year (2000) The following data are stored: Hourly concentrations of surface level ozone and NOx Daily mean concentrations of fine particulate matter Daily deposition of acidifying and eutrophying species Statistics of the impacts of Swedish aviation emissions in different countries are calculated (annual averages of impacts)

27. Deposition of oxidised nitrogen Aircraft emit NOx mainly in the form of NO NO is transformed in the atmosphere to NO2 and other oxidised nitrogen species, such as nitric acid, HNO3 The oxidised forms are finally deposited at the surface of plants, soils and water Deposition of oxidised nitrogen has several environmental effects Acidification of ecosystems and agricultural soil Fertilisation/Eutrophication of agricultural and natural ecosystems

28. Deposition of oxidised nitrogen

29. NOx-deposition effects on agriculture The economic effects on agriculture of NOx-deposition due to aircraft emissions are small Potential reduction of fertiliser use (i.e., savings): LTO emissions: 0.016 EUR / kg NOx Non-LTO emissions: 0.008 EUR / kg NOx Potential increase in liming cost to counter acidification of agricultural soil: LTO emissions: 0.002 EUR / kg NOx Non-LTO emissions: 0.0009 EUR / kg NOx

30. NOx-deposition valuation of ecosystem effects – based on abatement costs ExternE projects have used relatively high abatement cost estimates for acidification and eutrophication of ecosystems 176 000 € / km2 for acidification 25 900 € / km2 for eutrophication Vermoote and DeNocker (2003) developed a “Standard Price” approach to be compatible with the ExternE methodology and estimate an abatement cost of 10 000 € / km2 both for acidification and eutrophication

31. Acidification of ecosystems Estimated costs due to acidification of ecosystems Using standard ExternE valuation: LTO emissions: 4.57 EUR / kg NOx Non-LTO emissions: 1.09 EUR / kg NOx Using Vermoote & DeNockers Standard Price approach: LTO emissions: 0.26 EUR / kg NOx Non-LTO emissions: 0.06 EUR / kg NOx

32. Eutrophication of ecosystems Estimated costs due to eutrophication of ecosystems Using standard ExternE valuation: LTO emissions: 2.60 EUR / kg NOx Non-LTO emissions: 0.76 EUR / kg NOx Using Vermoote & DeNockers Standard Price approach: LTO emissions: 1.00 EUR / kg NOx Non-LTO emissions: 0.29 EUR / kg NOx

33. Impact on ozone concentrations near ground In the presence of sunlight and organic compounds NOx-emissions can lead to formation of ozone, O3 Ozone is very toxic to plants Ozone is harmful to humans Ozone is a strong greenhouse gas

34. Ozone – daily max 8h-mean conc

35. Ozone – population weighted exposure

36. Ozone – population weighted exposure

37. Ozone - valuation of impact on mortality Impact on mortality – 0.3% risk increase per 10mg/m3 increase in, maximum daily 8-h mean, concentration (short-term exposure) Only applied for persons above 30years old Assumed 1 year lost of life The value of a lost year of life was set to 73 000 EUR (In earlier ExternE studies the risk was set to 0.59% and the value of a lost year of life was set to 160 000 EUR)

38. Ozone - valuation of impact on mortality The resulting estimated marginal cost for life years lost by ozone exposure due to aviation NOx-emissions in Swedish air space are: 0.038 EUR/kg NOx for LTO emissions (or 0.16 EUR using ExternE valuation) 0.039 EUR/kg NOx for non-LTO emissions (or 0.17 EUR using ExternE valuation)

39. Ozone and Particulate Matter- valuation of impacts on morbidity Impact on morbidity – considered effects: Chronic bronchitis Hospital admissions Cerebrovascular disease Heart failure Respiratory diseases (chronic cough, restricted activity)

40. Monetary values for morbidity (EUR)

41. Valuation of morbidity impacts - uncertainties According to a recent WHO review there are few European ozone studies using other endpoints than daily number of deaths. A few studies on hospital admissions did not show a significant overall estimate in single pollution models, which may be a result of a negative correlation between ozone and primary combustion products. Neither did studies on admissions for asthma in children find conclusive associations, which may be explained by increased medication when ozone levels are high. Studies of ozone exposure and asthma incidence and prevalence in children and adults are not consistent. Available evidence suggests that long-term exposure possibly reduces lung function growth in children.

42. Valuation of morbidity impacts - uncertainties For the purpose of this study we have chosen not to update the Exposure-Response (ER) relations for impacts on morbidity due to ozone and PM. Instead we indicate that the morbidity effects are in the range between zero and the ExternE estimates. This is in line with the assumptions made in the CAFÉ (Clean Air For Europe) work where morbidity is excluded in the analysis of abatement costs.

43. Ozone - valuation of impact on morbidity The resulting estimated marginal cost for morbidity by ozone exposure due to aviation NOx-emissions in Swedish air space are: For LTO emissions: 0 – 0.29 EUR / kg NOx For non-LTO emissions: 0 – 0.30 EUR / kg NOx

44. Crop losses due to ozone exposure Elevated concentrations of ozone damages plants and thereby may lead to crop losses Slightly sensitive crops include: rye, oats and rice Sensitive include wheat, barley, potato and sunflower Very sensitive include tobacco Damage to crops are assumed to be linearly dependent on accumulated ozone exposure above a certain threshold concentration (AOT40)

45. Impact on accumulated ozone exposure - AOT40

46. Impact on accumulated ozone exposure - crops and natural vegetation - AOT40 May-July

47. Valuation of crop losses due to ozone exposure Valuation of crop losses was based on national producer prices for the year 2000 for the different crops considered. Data were taken from EUROSTAT. Two different sets of dose-response relationships for various crops were used, one compiled by Friedrich and Bickel 2001 (ExternE) and an updated set by Holland et al. (2002)

48. Valuation of crop losses due to ozone exposure The Holland (2002) ER relationships give the costs LTO emissions: 0.03 EUR / kg NOx Non-LTO emissions: 0.05 EUR / kg NOx The ExternE ER relationships give the costs LTO emissions: 0.09 EUR / kg NOx Non-LTO emissions: 0.12 EUR / kg NOx

49. Impact on fine particulate matter - PM2.5

50. Indirect influence of NOx-emissions on concentrations of PM

51. Impact on fine particles - PM2.5

52. PM - valuation of impact on mortality Impact on mortality: 6% risk increase per 10mg/m3 increase in, PM10 concentration, (long-term exposure) Only applied for persons above 30years old Assumed 1 year lost of life The value of a lost year of life was set to 49 000 EUR (In earlier ExternE studies the risk was set to 2.6% and the value of a lost year of life was set to 93 000 EUR)

53. PM - valuation of impact on mortality The resulting estimated marginal cost for life years lost by PM exposure due to aviation NOx-emissions in Swedish air space are: 0.20 EUR/kg NOx for LTO emissions (or 0.16 EUR using ExternE valuation) 0.13 EUR/kg NOx for non-LTO emissions (or 0.10 EUR using ExternE valuation)

54. Valuation of morbidity impacts - uncertainties The exposure-response relationships used in the ExternE calculations regarding the effects of PM on hospital admissions can be questioned for several reasons: The ER relations have been taken from a limited number of studies The base frequencies of incidence of hospital admissions used in the calculations were not taken from the nations or regions to which the calculations were applied. The scientific basis for using different coefficients for nitrates and PM10 and sulphates and PM2.5 can also be questioned. There are new risk factors for hospital admissions due to respiratory diseases and hospital admissions for cerebrovascular diseases due to PM10 available from the EU-projects Air Pollution and Health: A European Information System (APHEIS) (www.apheis.net) and APHEA2 (Short-term effects of Air Pollution on Health: a European Approach using epidemiological time-series; LeTertre, 2003). For chronic bronchitis updated risk factors are lacking.

55. Valuation of morbidity impacts - uncertainties For the purpose of this study we have chosen not to update the Exposure-Response (ER) relations for impacts on morbidity due to ozone and PM. Instead we indicate that the morbidity effects are in the range between zero and the ExternE estimates. This is in line with the assumptions made in the CAFÉ (Clean Air For Europe) work where morbidity is excluded in the analysis of abatement costs.

56. PM - valuation of impact on morbidity The resulting estimated marginal cost for morbidity by PM exposure due to aviation NOx-emissions in Swedish air space are: For LTO emissions: 0 – 0.08 EUR / kg NOx For non-LTO emissions: 0 – 0.05 EUR / kg NOx

57. Total LTO NOx emission costs (1 SEK ˜ 0.11 EUR)

58. Total non-LTO NOx emission costs (1 SEK ˜ 0.11 EUR)

59. Conclusions Marginal costs for NOx emissions from aviation in Swedish air space are estimated to be higher for LTO emissions than for non-LTO emissions LTO-emissions: ca 1.9 EUR (17 SEK) / kg NOx Non-LTO-emissions: ca 0.9 EUR (8 SEK) / kg NOx The costs due to acidification and eutrophication of natural ecosystems dominate but they are very uncertain. If ecosystem effects are excluded the marginal costs become almost the same for LTO and non-LTO emissions of NOx. LTO-emissions: 0.25-0.63 EUR / kg NOx Non-LTO-emissions: 0.21-0.56 EUR / kg NOx Costs due to crop loss and effects on agricultural soils were estimated to be much smaller than costs due to health effects.

60. Conclusions

61. Conclusions The total calculated costs for NOx emissions from aviation in Swedish air space are estimated to be about two times higher for non-LTO emissions than for LTO emissions LTO-emissions: ca 1.7 M EUR Non-LTO-emissions: ca 4.4 M EUR Using ExternE methodology and the higher abatement cost for ecosystem damages lead to higher costs LTO-emissions: ca 7.2 M EUR Non-LTO-emissions: ca 13 M EUR

62. Conclusions

63. Future work Future work to improve the present assessment of environmental costs due to aviation emissions of NOx are needed in all links of the Impact Pathway chain A number of uncertainties have been identified. The following topics should be considered in future studies Use of improved ER-relations and valuation of morbidity due to both PM and ozone – ongoing work for road traffic scenarios Grid based assessment of all the effects studied instead of nation averaging – better population data available now Calculations for more than one year in order to reduce the impact of meteorological variability

64. Uncertainties The valuation of ecosystem effects includes a number of uncertainties The mapping of ecosystem sensitivity varies to some extent between different countries and the valuation is based on abatement costs. The method for calculating the change in unprotected ecosystem area in the present study is based on country average critical loads. This also introduces some uncertainty. A more detailed approach would be to make calculations on a grid square by grid square basis, using grid square specific critical loads. This is possible but was outside the scope of the present study.

65. Uncertainties We have not used updated ER relations for effects on morbidity in this study. There are new European studies for hospital admissions, but for chronic bronchitis updated risk factors are lacking, and the calculations are based on one old study from the USA. An additional problem is the valuation of morbidity effects. The valuation can be expected to vary between countries but such information is lacking for many health outcomes. We have used the ExternE ER relations and valuation to indicate the possible magnitude of the morbidity costs but the uncertainties here are substantial.

66. Uncertainties PM formed from aviation NOx emissions is mostly nitrate in this study. Is nitrate really dangerous? Studies on animals do not indicate that ammonium nitrate in itself is toxic in relevant concentrations. However, when the short-term effect of PM in the US was compared between regions, California with the highest nitrate proportion had an ER-coefficient above the average. A few studies of short-term effects on mortality have also shown that nitrate particulates seem important, but maybe not due to nitrate in itself.

67. Uncertainties The sensitivity of different chemical transport models to changes in emissions is an important area of uncertainty. This appears to be the most important factor explaining the differences in valuation of health effects due to PM in this study. Harmonisation of chemical transport models is certainly an important topic here. Part of the explanation could also be related to the choice of time period for the modelling. Meteorological conditions are known to be important and simulations for different years are expected to give different results.

68. Further information