8.2.4.1 The Evaluation of the Ancillary Public Health Impacts

Studies estimating ancillary public health impacts from climate policies were examined, relying on three surveys of this literature (Ekins, 1996; Burtraw et al., 1999; Kverndokk and Rosendahl, 2000) and on summaries of the older literature, supplemented by some of the newer studies. Table 8.5 provides a description of each study, as well as the estimates of ancillary benefits per tonne of carbon. Table 8.6 summarizes the modelling choices of the studies reviewed.

Table 8.5: Scenarios and results of studies on ancillary benefit reviewed
Study	Area and sectors	Scenarios (1996 US$)	Average ancillary benefits US$/tC; 1996 US$)	Key pollutants	Major endpoints
Dessus and O’Connor, 1999	Chile (benefits in Santiago only)	Tax of US$67 (10% carbon reduction) Tax of US$157 (20% carbon reduction) Tax of US$284 (30% carbon reduction)	251 254 267	Seven air pollutants	Health—morbidity and mortality,
Cifuentes et al., 2000	Santiago, Chile	Energy efficiency	62	SO2, NOx, CO, NMHC Indirect estimations for PM10 and resuspended dust	Health
Garbaccio et al., 2000	China – 29 sectors (4 energy)	Tax of US$1/tC Tax of US$2/tC	52 52	PM10, SO2	Health
Wang and Smith, 1999	China – power and household sectors	Supply-side energy efficiency improvement Least-cost per unit global-warmingreduction fuel substitution Least-cost per unit human-air-pollutionexposure- reduction fuel substitution		PM, SO2	Health
Aunan et al. 2000, Kanudia and Loulou , 1998a	Hungary	Energy Conservation Programme	508	TSP, SO2, NOx, CO, VOC, CO2, CH4, N2O	Health effects; materials damage; vegetation damage
Brendemoen and Vennemo, 1994	Norway	Tax US$840/tC	246	SO2, NOx, CO, VOC, CO2, CH4, N2O, Particulates	Indirect: health costs; lost recreational value from lakes forests, ; corrosion Direct: traffic noise, road maintenance, congestion, accidents
Barker and Rosendahl, 2000	Western Europe (19 regions)	Tax US$161/tC	153	SO2, NOx, PM10	Human and animal health and welfare, materials, buildings and other physical capital, vegetation
Scheraga and Leary, 1993	USA	US$144/tC	41	TSP, PM10, SOx, NOx, CO, VOC, CO2, Pb	Health – morbidity and mortality
Boyd et al., 1995	USA	US$9/tC	40	Pb, PM, SOx, SO4, O3	Health, visibility
Abt Associates and Pechan-Avanti Group, 1999	USA	Tax US$30/tC Tax US$67/tC	8 68	Criteria pollutants	Health – mortality and illness; Visibility and household soiling (materials damage)
Burtraw et al., 1999	USA	Tax US$10/tC Tax US$25/tC Tax US$50/tC	3 2 2	SO2, NOx	Health
NMHC, non-methane hydrocarbons; PM, particulate matter; PM10, particulate matter less than 10 microns; TSP, total suspended particulate; VOC, volatile organic compounds; IQ, intelligence quotient

The Burtraw et al. (1999) review of US ancillary benefit studies of public health impacts linked to mitigation policies applied to the electricity sector came to several important conclusions:

• Estimates from early studies of ancillary benefits tended to exceed later ones because of the former’s use of more crude and less disaggregate modelling.
  
• Studies that did not factor into the baseline the reductions in conventional pollutants required under the 1990 Clean Air Act estimated benefits an order of magnitude larger than the studies that did include the 1990 Clean Air Act in the baseline. Analyzing Ekins (1996), Burtraw et al. (1999) found that whether the Second Sulphur Protocol is added to the baseline or not can alter the estimate of ancillary benefit by over 30%.
  
• Some studies did not consider the “bounceback” effect (i.e., the offsetting increase in conventional pollutants) when a less carbon-intensive technology is substituted for a more intensive one in response to a carbon mitigation policy.
  
• Ancillary benefit estimates are very sensitive to assumptions about the mortality risk coefficient and the value of statistical life (VSL). Routine values used in the literature can lead to a difference of 300% in ancillary benefit estimates.
  
• Burtraw et al. (1999) and earlier studies to reconcile US and European estimates for the social costs of fuel cycles found that population density differences between Europe and the USA account for 2 to 3 times larger benefit estimates in Europe. Also, the fact that much East Coast US pollution is blown out to sea while European pollution is blown inland can account for large ancillary benefit differences.
  
• With a cap on SO₂ emissions, abatement cost savings are considered ancillary benefits of a carbon policy unless the reductions are so large that the cap becomes non-binding. When this happens, with SO₂ effects on mortality being as large as they appear to be, ancillary benefits increase in a discontinuous and rapid fashion, as the health benefits begin to be counted.

Kverndokk and Rosendahl (2000) review much of the recent ancillary benefit literature in the Nordic countries, UK, and Ireland, concluding that benefits are of the same order of magnitude as gross (i.e., private) mitigation costs. They also conclude that the benefits should be viewed as highly uncertain, because of the use of simplistic tools and transfers of dose–response and valuation functions from studies done in other countries. They point out that most of the Norwegian studies use expert judgement instead of established dose–response functions and estimates of national damages per tonne rather than distinguishing where emissions changes occur and exposures are reduced. Also, they point out that large differences in ancillary benefits per tonne across several Norwegian studies can be attributed to differences in energy demand and energy substitution elasticities. If energy production is reduced rather than switched to less carbon-intensive fuels, ancillary benefits will be far larger. Kverndokk and Rosendahl (2000) point out also that studies that feed environmental benefits back into the economic model add significantly to ancillary benefits.

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