## Appendix D

Health Impacts from On-Road Diesel VehiclesD-1



### Assessment of Health Impacts from On-Road Diesel Ve hicles

A. Methodology

Details on the methodology used to calculate these estimates can be found in Appendix
A of the Emission Reduction Plan for Ports and Good s Movement in California (CARB, 2006).

1. Primary Diesel PM

As part of the development of emission reduction pl ans and control measures for particulate matter, including that for ports and go ods movement, the California Air Resources Board quantifies some of the health impac ts of exposure to current and future levels of ambient PM. The estimation of pre mature death and other health impacts from PM exposure used by CARB staff is base d on a peer-reviewed methodology developed by the U.S. Environmental Pro tection Agency for their risk assessments (US EPA, 1999, 2004, 2005). This metho dology is regularly updated by CARB staff as new epidemiological studies and other related studies are published that are relevant to California’s health impacts analysi s. The methodology uses concentration-response functions which describe the relation between exposure to ambient PM2.5 concentration and premature death and illness. The selection of the concentration-response functions was based on the l atest epidemiologic literature, as
described in Emission Reduction Plan for Ports and Goods Movement in California (CARB, 2006) and Methodology for Estimating the Pre mature Deaths Associated with Long-term Exposure to Fine Airborne Particulate Mat ter in California (CARB, 2008). The central estimate of the relative risk of premat ure death used in this assessment is a 10% per 10 μg/m 3 increase in PM2.5 exposures, with a confidence int erval of 3% - 20% (CARB, 2008).

For this analysis, staff used a “tons per incident” approach to estimate the health impacts associated with emissions from the on-road trucks and buses. Using the estimated diesel PM concentration for year 2005 (1. 6 μg/m 3 ), the diesel PM2.5 emissions for year 2005 (37,800 tons), and the conc entration-response functions for mortality and morbidity (CARB 2006, 2008), we estim ated the number of tons per year of primary diesel PM that can be associated with ea ch case of health endpoint for the year 2005 in California.

For example, using this information for premature m ortality, we estimate that for a reduction of 10.8 tons diesel PM2.5 emissions per y ear, one fewer premature death would result. This factor is derived by first dete rmining the total number of premature deaths from exposure to 1.6 μg/m 3 of diesel PM2.5, which was estimated to be 3,500 per year. Then the total annual diesel PM2.5 inven tory (37,800 tons) is divided by 3,500 premature deaths to calculate the factor of t ons per premature death. Although a single statewide factor (tons per case of health en dpoint) is discussed in this example, staff actually developed basin-specific factors for the health impacts assessment of
emissions from on-road trucks and buses. These bas in-specific factors were developedD-2

using basin-specific diesel PM concentrations and e missions for the year 2005. The basin-specific factors were applied to each air bas in to estimate health impacts.

a. Health Impacts of Diesel PM Baseline Emissions

After adjusting for population changes, staff estim ates that baseline PM emissions from in-use on-road diesel vehicles in the years 2010 to 2025 are associated with approximately 1100 annual premature deaths (330 – 2 000, 95% CI). Estimates of other health impacts, such as hospitalizations and asthma symptoms, were calculated using basin-specific factors developed from other health studies, basin-specific diesel PM concentrations, and emissions. Details for these e stimates can be found in Appendix A
of the Emission Reduction Plan for Ports and Goods Movement in California (ARB, 2006).

b. Benefits of Diesel PM Emissions Reductions

After adjusting for population changes between each future year and 2005, staff estimates that the cumulative total of approximatel y 34,600 tons of PM2.5 emissions from on-road trucks reduced through implementation of this regulation in years 2010 – 2025 are associated with a reduction of approximate ly 3,300 deaths (990 – 6,000, 95% CI). Estimates of other health benefits, such as h ospitalizations and asthma symptoms, were calculated using basin-specific factors develo ped from other health studies.

2. Secondary Diesel PM

In addition to directly emitted PM, diesel exhaust contains NOx, which is a precursor to nitrates, a secondary diesel-related PM formed in t he atmosphere that can lead to additional health impacts beyond those associated w ith directly emitted diesel PM2.5. To quantify such impacts, staff developed populatio n-weighted nitrate concentrations for each air basin using data not only from the statewi de routine monitoring network, which was used in Lloyd and Cackette (2001), but also fro m special monitoring programs such as IMPROVE and Children’s Health Study (CHS) in yea rs 2004, 2005 and 2006. The IMPROVE network provided additional information in the rural areas, while the CHS
added more data to southern California. Staff calc ulated the health impacts resulting from the three-year average exposure to these conce ntrations of PM2.5 and then associated the impacts with the basin-specific NOx emissions from diesel sources to develop basin-specific factors (tons per incident). The basin-specific factors and emissions were applied to each air basin to estimat e health impacts. Other health

effects were also estimated as outlined above.

Using an approach similar to that used for primary diesel PM and adjusting for population changes between each future year and 200 5, staff estimates that the cumulative reduction of approximately 480,000 tons of NOx emissions from the implementation of the on-road truck rule from 2010 to 2025 are associated with the reduction of an estimated 6,100 premature deaths (1 ,800 – 11,000, 95% CI). Other

health effects were also estimated as outlined abov e.D-3

3. Assumptions and Limitations of Health Impacts As sessment

There are a number of uncertainties involved in qua ntitatively estimating the health impacts associated with exposure to outdoor air pol lution. They include the selection and applicability of the concentration-response fun ctions, the exposure assessment,
and the baseline incidence rates. These are briefl y described below.

• A primary uncertainty is the choice of the specifi c studies and the associated concentration-response (C-R) functions used for qua ntification. Epidemiological studies used in this report have undergone extensiv e peer review and include sophisticated statistical models that account for t he confounding effects of other pollutants, meteorology, and other factors. While there may be questions on whether C-R functions from the epidemiological stud ies are applicable to California,

it should be noted that some of the cities in the A CS cohort are in California. Also, studies have shown that the mortality effects of PM in California are fairly consistent
with those found in other locations in the United S tates (Dominici et al. 2005, Franklin et al. 2007, Jerrett et al. 2005; Pope et al. 2002). The C-R function for PM2.5-related mortality used in this report was bas ed on a careful review of all relevant scientific literature and a thorough consi deration of each study’s strengths and limitations. In addition, it was approved by o ur advisors and independent peer

reviewers.

• In this assessment, staff assumed diesel PM is as toxic as ambient PM2.5. However, this approach may underestimate the true e ffects of diesel PM exposure
on adverse health outcomes. Indirect evidence for this possibility comes from a
number of studies that link motor vehicle-related P M exposure to premature death including: Elderly people living near major roads had almost twice the risk of dying from cardiopulmonary causes (Hoek et al., 2000); PM from motor vehicles was linked to increased mortality (Tsai et al., 2000); PM2.5 from mobile sources accounted for three times the mortality as did PM2. 5 from coal combustion sources (Laden et al., 2000).

• This report estimated health impacts due to emissi ons. The methodology applies a “tons per incident” factor to estimate the number o f health effects associated with

PM2.5 emissions and assumes the emissions are evenl y distributed within the air

basin.

• CARB staff assumed the baseline incidence rate for each health endpoint was uniform across each county. This assumption is con sistent with methods used by the U.S. EPA for its regulatory impact assessment, and the incidence rates match those used by U.S. EPA.

• Although the analysis illustrates that diesel PM e xposure would be associated with health effects to people living in California, we d id not provide estimates for all endpoints for which there are C-R functions availab le. Health effects such as myocardial infarction (heart attack), chronic bronc hitis, and onset of asthma were unquantified due to the potential overlap with the quantified effects such as lowerD-4

respiratory symptoms and hospitalizations. In addi tion, estimates of the effects of PM on low birth weight and reduced lung function gr owth in children are not presented. While these endpoints are significant i n an assessment of the public health impacts of diesel exhaust emissions, there a re currently few published investigations on these topics, and the results of the available studies are not entirely consistent (CARB, 2006). In summary, beca use only a subset of the total number of health outcomes is considered here, the e stimates should be considered an underestimate of the total public health impact of diesel PM exposure.

B. Health Impacts Associated with Baseline Diesel P M Emissions

Staff estimates that approximately 4,500 premature deaths (1,400 – 8,000, 95 percent confidence interval (95% CI)) are associated with t he baseline uncontrolled emissions from on-road trucks and buses in the year 2008. Ot her health impacts are listed in the Table 1. The methodology for estimating these heal th impacts is outlined below. Details can be found in Appendix A of the Emission Reduction Plan for Ports and Goods Movement in California (CARB, 2006).

Compared to the estimate for truck emissions presen ted in the CARB 2006 report, the health impacts presented here differ due to the fol lowing reasons:
1) The concentration-response function relating cha nges in long-term PM2.5 exposure to risk for premature death was updated fr om Pope et al. 2002 to CARB (2008);

2) The category of “trucks” was expanded to include medium heavy duty trucks or buses;
3) Emissions were estimated based on EMFAC2007;

4) Spatial allocation was updated to reflect real-w orld variation in emissions throughout California.

In short, the current estimated emissions and the a ssociated health impacts presented in this report are the most up-to-date and reflect the most current understanding on the subject matter.D-5

Table 1: Baseline Health Impacts Associated With Emission from

On-Road Trucks and Buses for year 2008*

Endpoint Pollutant # of Cases
95% C.I. (Lower Bound) # of Cases

(Mean) # of Cases

95% C.I. (Upper Bound)

PM 330 1,100 2,000

NOx 1,000 3,400 6,000 Premature Death

Total 1,400 4,500 8,000

PM 8 21 35

NOx 320 560 830 Hospital admissions (Respiratory) Total 330 590 860

PM 47 90 130

NOx 330 530 780 Hospital admissions (Cardiovascular)

Total 380 620 910

PM 6,900 18,000 28,000
NOx 21,000 53,000 83,000 Asthma & Lower Respiratory Symptoms Total 28,000 71,000 110,000

PM 0 1,500 3,200
NOx 0 4,200 8,700 Acute Bronchitis

Total 0 5,700 12,000

PM 93,000 110,000 130,000

NOx 290,000 340,000 390,000 Work Loss Days

Total 380,000 450,000 520,000
PM 520,000 640,000 760,000

NOx 1,600,000 2,000,000 2,300,000 Minor Restricted Activity Days Total 2,100,000 2,600,000 3,100,000

* Health effects from primary and secondary PM are la beled PM and NOx, respectively. The sum of PM and NOx impacts may not equal the total given due t o rounding. Estimates for premature deaths are based on an updated relative risk of 10% per 10 μg/ m 3 change in long-term PM2.5 exposure, with a confidence interval of 3% - 20% (CARB, 2008).

C. Health Benefits of Reduction in Emissions from I n-Use Off-Road Vehicles

A substantial number of epidemiologic studies have found a strong association between exposure to ambient PM2.5 and a number of adverse health effects (CARB, 2002) . For this report, ARB staff quantified seven noncancer h ealth impacts associated with the change in exposures to the diesel PM emissions. Th is analysis shows the statewide cumulative health impacts of the emissions reduced through this regulation from year 2010 through 2025. Staff estimates that the cumula tive emissions reductions would result in approximately 9,400 fewer premature death s. Other health impacts are listed

below in Table 2.D-6

The impacts associated with primary PM and secondar y PM diesel emissions are listed separately. The methodology for estimating these h ealth impacts is outlined above and details can be found in Appendix A of the Emission Reduction Plan for Ports and Goods Movement in California (CARB, 2006).

Table 2: Total Health Benefits Associated with Reductions in Emissions from the

Implementation of the On-Road Truck and Bus Regulat ion (2010-2025)*

Endpoint Pollutant # of Cases 95% C.I. (Lower Bound) # of Cases

(Mean) # of Cases

95% C.I. (Upper Bound)

PM 990 3,300 6,000

NOx 1,800 6,100 11,000 Premature Death

Total 2,800 9,400 17,000

PM 23 64 110

NOx 580 1,000 1,500 Hospital admissions (Respiratory)

Total 600 1,100 1,600

PM 140 270 400

NOx 590 960 1,400 Hospital admissions (Cardiovascular)

Total 730 1,200 1,800

PM 20,000 53,000 85,000

NOx 39,000 96,000 150,000 Asthma & Lower Respiratory Symptoms Total 59,000 150,000 230,000

PM 0 4,400 9,600

NOx 0 7,600 16,000 Acute Bronchitis

Total 0 12,000 25,000

PM 280,000 330,000 380,000

NOx 520,000 620,000 710,000 Work Loss Days

Total 800,000 950,000 1,100,000

PM 1,600,000 1,900,000 2,300,000

NOx 2,900,000 3,600,000 4,200,000 Minor Restricted Activity Days
Total 4,500,000 5,500,000 6,500,000

* Health effects from primary and secondary PM are la beled PM and NOx, respectively. The sum of PM and NOx impacts may not equal the total given due t o rounding. Estimates for premature deaths are based on an updated relative risk of 10% per 10 μg/ m 3 change in long-term PM2.5 exposure, with a confidence interval of 3% - 20% (CARB, 2008).D-7

D. Economic Valuation of Health Effects

This section describes the methodology for monetizi ng the value of avoiding adverse health impacts.

The U.S. EPA has established $4.8 million in 1990 d ollars at the 1990 income level as the mean value of avoiding one premature death (U.S . EPA, 1999). This value is the mean estimate from five contingent valuation studie s and 17 wage-risk studies. Contingent valuation and wage-risk studies examine the willingness to pay (or accept payment) for a minor decrease (or increase) in the risk of premature death. For example, if individuals are willing to pay $800 to reduce their risk of mortality by 1/10,000, then collectively they are willing to pay $8 million to avoid one death. This is

also known as the “value of a statistical life” or VSL. 1

As real income increases, people are willing to pay more to prevent premature death. U.S. EPA adjusts the 1990 value of avoiding a prema ture death by a factor of 1.201 2 to account for real income growth from 1990 through 20 20, (U.S. EPA, 2004). Assuming that real income grows at a constant rate from 1990 until 2030, we adjusted VSL for real income growth, increasing it at a rate of approxima tely 0.6% per year. We also updated the value to 2007 dollars. After these adjustments , the value of avoiding one premature death is $8.9 million in 2007, $9.2 million in 2010 and $10 million in 2025, all expressed

in 2007 dollars.

The U.S. EPA also uses the willingness-to-pay (WTP) methodology for some non-fatal health endpoints, including lower respiratory sympt oms, acute bronchitis and minor restricted activity days. WTP values for these min or illnesses are also adjusted for anticipated income growth through 2025, although at a lower rate (about 0.2% per year in lieu of 0.6% per year).

For work-loss days, the U.S. EPA uses an estimate o f an individual’s lost wages, (U.S. EPA, 2004), which CARB adjusts for projected real i ncome growth, at a rate of approximately 1.5% per year.

“The Economic Value of Respiratory and Cardiovascul ar Hospitalizations,” (CARB, 2003), calculated the cost of both respiratory and cardiovascular hospital admissions in California as the cost of illness (COI) plus associ ated costs such as loss of time for work, recreation and household production. When ad justing these COI values for inflation, CARB uses the Consumer Price Index (CPI) for medical care rather than the
CPI for all items.

1 U.S. EPA’s most recent regulatory impact analyses, (U.S. EPA 2004, 2005), apply a different VSL estimate ($5.5 million in 1999 dollars, with a 95 p ercent confidence interval between $1 million and $ 10 million). This revised value is based on more recen t meta-analytical literature, and has not been endo rsed by the Environmental Economics Advisory Committee ( EEAC) of U.S. EPA’s Science Advisory Board (SAB). Until U.S. EPA’s SAB endorses a revised esti mate, CARB staff continues to use the last VSL estimate endorsed by the SAB, i.e., $4.8 million in 1990 dollars.

2 U.S. EPA’s real income growth adjustment factor fo r premature death incorporates an elasticity estima te
of 0.4.D-8

Table 3 lists the valuation of avoiding various hea lth effects, compiled from CARB and U.S. EPA publications, updated to 2007 dollars. Th e valuations based on WTP, as well as those based on wages, are adjusted for anticipat ed growth in real income.

Benefits from the proposed rule for on-road trucks are substantial. CARB staff estimates cumulative benefits over the period from 2010 to 2025 to be $69 billion using a 3% discount rate or $48 billion using a 7% discou nt rate 3 . A large proportion of the monetized benefits results from avoiding premature death. The estimated benefits from avoided morbidity are approximately $510 million wi th a 3% discount rate and nearly $350 million with a 7% discount rate. Approximatel y 68% of the benefits are associated with reduced PM from NOx emissions, and the remaini ng 32% from direct PM

emissions.

Table 3: Undiscounted Unit Values for Health Effect s

(at various income levels in 2007 dollars) 1

Health Endpoint 2007 2010 2025 References

Mortality

Premature death ($ million) 8.9 9.2 10 U.S. EPA (1999, p. 70-72, 2000, 2004, p. 9-121)

Hospital Admissions
Cardiovascular ($ thousands) 36 37 54 CARB (2003), p. 63

Respiratory ($ thousands) 44 45 44 CARB (2003), p. 63

Minor Illnesses

Acute Bronchitis 452 455 471 U.S. EPA (2004), 9-158

Lower Respiratory Symptoms 20 20 21 U.S. EPA (2004), 9-158

Work loss day 191 201 260 2002 California wage data, U.S. Department of Labor

Minor restricted activity day (MRAD) 64 64 67 U.S. EPA (2004), 9-159

1 The value for premature death is adjusted for proje cted real income growth, net of 0.4 elasticity. Wag ebased values (Work Loss Days) are adjusted for proj ected real income growth, as are WTP-derived values (Lower Respiratory Symptoms, Acute Bronchiti s, and MRADs). Health endpoint values based on cost-of-illness (Cardiovascular and Respiratory Hos pitalizations) are adjusted for the amount by which projected CPI for Medical Care (hospitalization) ex ceeds all-item CPI.

3 CARB follows U.S. EPA practice in reporting result s using both 3% and 7% discount rates.D-9

E. Conclusion

The health benefits of implementing the proposed re gulation are substantial. Staff

estimates that the cumulative emissions reductions over the lifetime of the rule can be associated with approximately 9,400 fewer premature deaths, 1,100 fewer hospital admissions due to respiratory causes, 1,200 fewer h ospital admissions due to cardiovascular causes, 150,000 fewer cases of asthm a-related and other lower respiratory symptoms, 12,000 fewer cases of acute b ronchitis, 950,000 fewer work loss days, and 5,500,000 fewer minor restricted activity days. The uncertainty behind each estimated benefit ranges from about 15% to 75% for most endpoints. The estimated
statewide benefits over 2010 to 2025 from these red uctions in adverse health effects is $48 billion using a 7% discount rate or about $69 b illion using a 3% discount rate.

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