Análisis de datos

Fraction to country j = djk 0 < d^k< 1 Country j where j = 1,..., n i.e. all the countries

other than i itself receiving emissions

from country i

From Figure A 3.1, it is clear that the following holds:

j-i -jk

[A3.1] where is the fraction o f emissions o f pollutant k from country i falling at

sea;

d i^ is the fraction o f emissions o f pollutant k from country i being deposited in country i itself; and

is the fraction o f emissions o f pollutant k from country i being deposited in country 7, where7 are all the other countries in the U N ECE.

Now assume that the physical damage caused by a tonne o f pollutant k (e.g. SO2, N O J deposited will be the same no matter which country it falls on, but zero for any depositions to sea:

^dep.ik — ^depjk [A3.2]

Where and are expression for the physical damage caused by 1 tonne o f pollutant k deposited in countries i and j respectively. As the physical damage per unit o f pollutant k deposited is assumed to be the same anywhere on land, it can be expressed simply as omitting the subscript denoting the receiving country.

D ^,sk = 0 [A3.3]

The expression [A3.3] shows the assumption that the physical damage caused by a tonne o f pollutant k deposited at sea is nil. The damage per tonne o f k emitted from country i can now be expressed as follows:

^anis.ik — ^ dep.k ' (1 ’ ^ik) [A3.4]

i.e. the physical damage per tonne deposited times the fraction o f emissions that is deposited on land. Alternatively, it can be expressed in more detail, attributing damage to each receiving country:

^ e n ü s ,ik ' ^dep,k * ^i-*ik ' ^dep,k ' W ] [A3.5]

The monetary value o f the damage done in all countries by the emissions o f 1 tonne o f k from country /, can be obtained by multiplying equation [A3.5] by the shadow price for damage caused by k:

^emis,ik

' ^dep,k * (1

' ^Jk

j

[ ^ i- * ik ‘ ^ d e p , k * (1 “ * ^ i k ]

where P,-* is the shadow price for damage caused by pollutant k in country /, and Py* is the shadow price for damage caused by pollutant k in country j .

In addition to multiple pollutants, Â: = 1 ,..., m (SO2, N O J, the notion o f multiple receptors, r =

1

^ em isjk ' ^ d e p ,k r ' % ) '

^ i-* ik ' ^ d e p .k r ' ( 1 ‘ ^ ik i\

[A3.7]

A3.2.2

Differences in Willingness to Pay

A second reason why the damage caused by the emissions o f 1 tonne o f k from two different countries may differ, is that the willingness to pay (WTP) may vary between countries. If the WTP is the same in all countries, then Py^ = Pj^. However, WTP is more likely to vary between countries, reflecting disparities in both relative income levels and the income elasticity o f demand for environmental quality between countries. The ideal approach would involve adjusting calculated national damage estimates to reflect these differences. While the former adjustment can be made quite easily by adjusting income levels using purchasing power parity rates, the latter adjustment is more difficult given the lack o f knowledge relating to the income elasticities o f demand for environmental quality for the EU Member States, let alone for all countries receiving air pollution from the EU States.

The hypothesis that environmental quality is a ‘luxury good’, i.e . a good which would primarily benefit the wealthy relative to the poor, has been challenged by Pearce (1980) and more recently by Kristrom & Riera (1994). Kristrom & Riera’s survey o f contingent valuation studies for Finland, France, Norway, Netherlands, Spain and Sweden indicates that very few studies support the view that income elasticities o f demand for environmental quality is greater than 1, and a number o f studies suggest income elasticities o f the order o f 0.3. This finding is supported by Pommerehne (1988) whose work, involving a comparison o f hedonic pricing and

contingent valuation results, likewise suggests an income elasticity o f 0.3. On the basis o f these studies, two adjustments for income elasticities o f demand for environmental quality are carried out; one where the income elasticity is assumed to be 1 and another where the income elasticity is assumed to be 0.3.

Thus on the basis o f an estimated shadow price for the damage caused by pollutant k in one country, the shadow price for another country can be estimated:

where P Y n e

= P . [A3.8]

the estimated shadow price in country m; the income at PPP rates;

the country whose shadow price is known; and

income elasticity o f demand for environmental quality

Substituting [A 3.8] for P in [A3.7] renders:

' ^ d e p ,k r ' ( 1 “ % ) * ^ n k r Jff e ; ^i-*ik ' ^ d e p ,k r * ^ik^ * ^ n k r [A3.9] A 3.2.3 Transboundary Pollution

The relevance o f critical loads was discussed in the main text o f Chapter 3. Tables A 3.2.1 and A 3.2.2 illustrate the relative country-to-country deposition matrices for oxidised sulphur and oxidised nitrogen respectively for U N ECE^. These are based on the average o f the absolute value matrices for the period 1985-1994 (Barrett, et al.y 1995). In the following, it is assumed that the pattern o f damage caused by atmospheric emissions o f SO2 and N0% follows the pattern o f depositions o f oxidised sulphur and nitrogen. This implies that as 28 per cent o f oxidised sulphur emissions

The UN ECE is all o f Europe including all o f Scandinavia and Central and Eastern Europe as opposed to just the European Union.

in the period 1985-1994 fell in the UK and around 50 per cent was deposited at sea, 56 per cent o f the damage caused by UK emissions will be incurred in the UK. Similarly, the five per cent o f UK emissions landing on Germany would account for nine per cent o f total damages caused by UK SO2 emissions (see Table A 3.2.1). This assumption introduces a further element o f uncertainty. As discussed in section A 3.1, the damage estimates for SO2 and NO% are in fact based on damage estimates for acidic aerosols (mainly ammonium sulphate, sulphuric acid and ammonium nitrate) which have been related to emission o f SO2 and N0% respectively. Thus, if sulphates account for, say, one third o f the total o f SO2 emissions, the damage estimate o f X ECU relates really only to that third. However, as the emissions are given in tonnes o f SO2 as opposed to tonnes o f sulphates, it is assumed that the damage caused by 1 tonne o f SO2 is X ECU - when really it is X ECU for 16 tonnes o f sulphates. This is a quite legitimate assumption to make - as long as the amount o f sulphate relative to SO2 (or ammonium nitrate relative to N O J remains constant. However, the EMEP Report (Barrett et a l., 1995) suggests that this may not always be the case, particularly in respect o f the sulphate - SO2 relationship:

... a larger fraction o f oxidised sulphur appears as SO2 than as

particulate sulphate over the mainland o f Europe, the ration often being more than 2:1. Moving towards the Mediterranean countries and Scandinavia the ratio approaches 1:1, with ratios favouring particulates at the margins o f the domain.

Barrett et al. (1995), p 26.

This implies that the assumption o f a constant relationship between sulphates and SO2 might result in an underestimate o f sulphate induced damage in Scandinavia and the Mediterranean, or an overestimate for Central Western Europe. However, following discussions with one o f the authors o f the Report (Holland, 1995), it was decided that little in terms o f improved accuracy could be achieved by attempting to correct for these differences, considering the large uncertainties already attached to the damage estimates.

Table A3.2.1

Relative Dispersion of Oxidised Sulphur Emissions - Average 1985-1994