monetizing the health impacts of wood smoke in the pacific northwest april 10, 2014

Monetizing the Health Impacts of Wood Smoke in the Pacific Northwest

April 10, 2014

Abt Associates | pg 2

Project Overview

Task A – Collect Data

Task B – Estimate Baseline Wood Smoke Emissions

Task C – Estimate Scenario Wood Smoke Emissions

Task D – Monetize Health Impacts


Baseline Wood Smoke Emissions

Data sources used to estimate baseline wood smoke emissions include the Residential Building Stock Assessment (RBSA) and the U.S. EPA Residential Wood Combustion (RWC) tool– RWC Tool: all counties in Oregon & Washington; Ada,

Canyon, & Elmore, Idaho; Lincoln & Silver Bow, Montana – RBSA: all other counties in Idaho and Montana



Baseline methodology relies on two key factors: Appliance fraction: the percentage of homes in the

county with each type of wood burning appliance Burn rate: the amount of wood (cords or tons) burned

in each appliance in each year Unique appliance fractions and burn rates are

calculated for each combination of appliance type, burn type, and house type



Appliance Burn Type House Type

Fireplace Primary Single-family

Wood stove (non-certified) Secondary Multi-family

Wood stove (certified non-catalytic) Manufactured homes

Wood stove (certified catalytic)

Fireplace insert (non-certified)

Fireplace insert (certified non-catalytic)

Fireplace insert (certified catalytic)

Pellet stove

Wood-fired furnace

Wood-fired boiler

Outdoor burning (e.g. firepits)



Baseline emissions calculation: Baseline emissions (tons) =

Number of homes × Appliance fraction ×

Burn rate (cords/year) ×

Density of firewood (tons/cord) ×

Emission factor (tons of pollution/tons of wood)

Number of appliances

Number of cords

Convert cords to tons

Calculate tons of pollution


Scenario Wood Smoke Emissions

Scenarios reduced emissions for all appliances used primarily for heating:– All types of wood stoves, pellet stoves, wood-fired furnaces, and wood-fired

boilers– Did not include fireplaces or outdoor burning (e.g. firepits); these emissions

were left unchanged Analysis included 4 scenarios:

– 25% reduction– 50% reduction– 75% reduction– 100% reduction


Baseline and Scenario Emissions


Monetized Health Impacts: Method

U.S. EPA’s Co-Benefits Risk Assessment (COBRA) modelQuantifies Changes in Air Quality- Uses a simple air quality model, the Source Receptor (S-R) Matrix, to estimate effects of

changes on ambient particulate matter.

Calculates Change in Health Outcomes- Uses “canned” concentration response functions to

link the changes in particulate matter to epidemiological studies

Outputs = Tables and maps of illnesses and deaths avoided and the

related economic value.

Calculates Monetary Value- Uses “canned” values based on willingness-to-

pay, cost of illnesses , value of a statistical life and direct medical costs.

Modified the baseline for wood smoke emissions to match estimates for the PNW

Adjusted the outputs for population and income growth to match council values


Monetized Health Impacts: Adjustments

Population adjustments– Using county-level ratios of the Council’s 2017

population projections to the 2017 population in COBRA

Income growth adjustments– For economic values, based on willingness-to-pay

estimates

– Using the ratio of Council data-based income growth adjustment factors to the factors supplied by EPA


Monetized Health Impacts: Results

Avoided cases of adverse health effects, and their associated economic values– “Low” and “high” estimates based on different (EPA-

approved) assumptions about sensitivity of adult mortality and non-fatal heart attacks to changes in ambient PM2.5 levels

– COBRA discounts the estimated stream of economic benefits to the year 2017, since some health benefits from 2017 emissions reductions will occur in later years



Health Incidence Results for Study AreaHealth Incident Avoided Number of Cases Avoided 25% Reduction 50% Reduction 75% Reduction 100% Reduction

Adult Mortality 55-126 111-251 166-376 222-501Infant Mortality >0 >0 >0 >0Non-fatal Heart Attacks 6-54 12-108 17-161 23-214Hospital Admissions 25 50 75 100Acute Bronchitis 91 182 273 364Respiratory Symptoms 2,829 5,654 8,476 11,295Asthma ER Visits 24 48 72 95MRAD 48,683 97,316 145,898 194,430Work Loss Days 8,220 16,435 24,645 32,849Asthma Exacerbations 1,745 3,489 5,232 6,975



Monetized Value Results for Study AreaHealth Incident Avoided Economic Value (Millions 2010$, 7% discount rate) 25% Reduction 50% Reduction 75% Reduction 100% ReductionTotal Health Effects $425.8 - $960.9 $851.3 - $1,920.0 $1,276.5 - $2,877.5 $1,701.3 - $3,833.3

Adult Mortality $418.1 - $947.4 $835.9 - $1,893.2 $1,253.3 - $2,837.3 $1,670.4 - $3,779.7

Infant Mortality $1.1 $2.1 $3.2 $4.3

Non-fatal Heart Attacks $0.7 - $6.4 $1.4 - $12.8 $2.1 - $19.1 $2.8 - $25.4

Hospital Admissions $0.8 $1.7 $2.5 $3.4

Acute Bronchitis >$0.0 $0.1 $0.1 $0.2

Respiratory Symptoms $0.1 $0.2 $0.2 $0.3

Asthma ER Visits >$0.0 >$0.0 >$0.0 >$0.0

MRAD $3.3 $6.6 $9.9 $13.2

Work Loss Days $1.6 $3.2 $4.8 $6.4

Asthma Exacerbations $0.1 $0.2 $0.3 $0.4



0% 25% 50% 75% 100%$0

$500

$1,000

$1,500

$2,000

$2,500

$3,000

$3,500

$4,000

$4,500

f(x) = 1701.31942174323 x + 0.334594038900832

f(x) = 3833.25397375823 x + 1.70010454201338

High EstimateLinear (High Estimate)

Wood Smoke Emissions Reduction

Tota

l Hea

lth B

enef

its (M

illio

ns $

)

0% 25% 50% 75% 100%0

100

200

300

400

500

600

f(x) = 221.532584143599 x + 0.0436241824237271

f(x) = 501.266276511229 x + 0.222011298122027

High Estimate

Wood Smoke Emissions Reduction#

of A

dult

Dea

ths

Avo

ided

Total Health Benefits in 2017 Avoided Adult Mortality in 2017



mg/m3 PM2.5

Improvements in Ambient Air Quality



Total Health Benefits



Changes in PM2.5 Emissions

Value of Total Health Effects Avoided



Comparing Health Benefits to Increased Electricity Usage Estimated the amount of electricity needed to displace wood heat with ductless

heat pumps (DHPs):– Usable heat to displace (kWh) = Wood burned (tons) × Btu/ton of wood × Appliance Efficiency × kWh/Btu

– Grid DHP Electricity Consumption (kWh) = Usable heat from woodstoves /

DHP COP × Grid Loss Factor

– Benefits per kWh = Total Health Benefits / DHP Electricity Consumption

Total benefits for PNW study area: $0.72 - $1.61 per kWh of electricity used by a DHP to displace wood heat


Applications and Limitations Applications

– Significant annual health benefits across PNW study area identified by screening-level assessment provide justification for performing a more in-depth analysis of benefits associated with wood smoke emissions reductions

– A value range ($/kWh) that can be used in a benefit-cost analysis of policies or programs that target the entire PNW study area to replace wood burning appliances with DHPs

– A customized version of COBRA to allow future scenario analyses

Limitations– Results can only be interpreted at the study-area level; more analysis is needed to

determine more spatially targeted results (e.g. county level)– Results only examine benefits, but do not include costs of reducing wood smoke or

for increases in emissions from EGUs (e.g. to power DHPs)– Analysis does not fully account for all uncertainties, including population and

income projections and air dispersion algorithms


Suggested Future Analyses

Spatially targeted results– Current results can only be interpreted across the entire study area– Spatially targeted results would look at smaller (e.g. county-level) areas to

determine benefits of emission reductions on a smaller spatial scale Compare benefits to costs of reducing wood smoke emissions

– Incentives to reduce burning and/or to install DHPs or other heating devices– Education campaigns to inform residents about wood smoke emissions– Regulations to control wood smoke emissions

Examine emissions from redispatching electricity– The current analysis does not adjust the benefits to account for any emissions

that might arise due to an increase in use of DHPs to displace wood heat


Acknowledgements

Special thanks to: Mohit Chhabra, Ptarmigan Research

Charlie Grist, Northwest Power and Conservation Council

RTF Wood Smoke Subcommittee

Ben Larson, David Baylon, Ecotope Inc.; Christian Douglass, Ptarmigan Research

Questions?Abt Contact Information

Jonathan G. Dorn, Ph.D., [email protected]

919-294-7763

monetizing the health impacts of wood smoke in the pacific northwest april 10, 2014

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