1 

## How PM Benefits were calculated for Boiler MACT and Boiler Area Source Rule

Overall Goal: T o produce benefit

- per

- ton estimates for major and area boilers to multiply by the

anticipated emission reductions for the Boiler MACT and Boiler Area Source Rule

Step 1: Update E missions D ata

We u se d the information from the Boiler Information Collection Request ( ICR ) to update National

Emissions Inventory (NEI)

. (Unable to incorporate all ICR data into NEI, as explained below )



## + =

Technical details are provided in “ Air Quality Modeling Technical Support Document: Boiler Source Sector

Rules ”

.

Step 2 : Run Air Quality Model

The u pdated NEI is an input to the CAMx model , which conver ts emissions to ambient PM 2.5 and ozone

concentrations and mercury deposition

.



## - > = >

Step 3: Extract Air Quality Data

Using source apportionment in CAMx

, we develop ed a national surface baseline (i.e., gridded air quality

predictions)

. Also, we create d surfaces that zero o ut p r i m a r y PM 2

. 5 and SO 2 emissions from point and

non

- point boilers

. We assume that point boilers are a surrogate for major boilers and non

- point boilers

are a surrogate for area boilers. We zero out these emissions to estimate the total impacts from boilers.



## = >

Technical details are provided in “ Air Quality Modeling Technical Support Document: Boiler Source Sector

Rules ”

. **•** Baseline PM 2.5 surface

**•** S urface with no PM from point boilers

**•** S urface w ith no PM from non

- point boilers

**•** S urface with no SO 4 from point boilers

**•** S urface with no SO 4 from non

- point boilers Ambient PM 2.5 and ozone

concentrations and mercury

deposition Updated NEI

(all emissions with

updated boiler data ) Updated NEI

(all emissions with

updated boiler data) NEI

(all emissions) Boiler ICR

data2 Step 4: Run Benefits Model

We ran the baseline and zero’d out surfaces through the BenMAP model to estimate total impacts

(monetized benefits and incidence) associated with boiler s ( point and non

- point ) for both PM precursor

e m i s s i o n s ( p r i m a r y PM 2

. 5 and SO 2 )

.

Baseline Air Quality Post

- Policy Scenario Air Quality

Incremental Air Quality
Improvement

PM 2.5 Reduction

Population
Ages 18

- 65 Background

Incidence

Rate

Effect

Estimate Mortality

Reduction Step 2: Apply Health
Impact Function

T echnical details are provided in Chapter 7 of the Boiler RIA

.

Step 5: Calculate Benefit

- per

- ton Estimates

We d ivide d the total impacts by the modeled emissions from boilers to create boiler

- specific benefit

per

- ton (BPT) estimates for point and non

- point boilers . We assume that point boilers are a surrogate

for major boile rs and non

- point boilers are a surrogate for area boilers.

Total Impacts from Point Boilers PM

Tons of PM from Point Boilers in Updated NEI = BPT PM Major

Total Impacts from Non

- Point Boilers PM

Tons of PM from Non

- Point Boilers in Updated NEI = BPT PM Area

Repeat to calculate BPT SO2 Majo r and BPT SO2 Area
. Technical details are provided in Chapter 7 of the Boiler

RIA

.

Step 6: Calculate Benefits of Regulatory Alternatives

We multiplied the new BPT estimates by the emission reductions associated with each regulatory

alternative

.

BPT SO2 Major * SO 2 reductions = Benefits from SO 2 for major sources

BPT PM Major * PM reductions = Benefits from PM for major sources3 BPT SO2 Area * SO 2 reductions = Benefits from SO 2 for area sources

BPT PM Area * PM reductions = Benefits from PM for area sources

Emission reductions associated with each regulatory alternative were calculated using average baseline

emission factors for a model boiler and emission limit s based on ICR data and permit limits. Technical

details are provided in the se docket memos : “ Revised Development of Baseline Emission Factors for

Boilers and Process Heaters at Commercial, Industrial, and Institutional Facilities ” and “ Revised

Methodolog y for Estimating Cost and Emissions Impacts for Industrial, Commercial, Institutional Boilers

and Process Heaters National Emission Standards for Hazardous Air Pollutants ”

.

Emission Differences

The table below shows the differences between the NEI and th e baseline emissions used for the

NESHAPs

. It was impossible to fully reflect the updated ICR data for boilers in the NEI because some

information was unavailable in the ICR including consistent Plant ID, geographic coordinates, SCC codes,

stack height, e xit temperature, exit velocity, speciation, etc. The NEI data and air quality modeling were

only used to create updated BPT estimates specifically for the boiler sector. All of the emission

reductions associated with the rule are calculated using the NES HAP emissions.

Facility * Pollutant NEI Baseline

Emissions NESHAP Baseline

Emissions

Major

Existing PM 2.5 28,990 63,833

SO 2 492,676 966,652

VOC 15,451 34,391

Hg 4 6.1

Major

New PM 2.5 - 30

SO 2 - 610

VOC

- 31

Hg

- 0.01

Area

Existing PM 2.5 108,386 32,784

SO 2 1,149,402 298,372

VOC 14,107 6,555

Hg

- 4.4

Area

New PM 2.5 - 1,362

SO 2 - 21,306

VOC

- 631

Hg

- 0.5

Total

Boilers PM 2.5 137,376 98,009

SO 2 1,642,078 1,286,940

VOC 29,558 41,608

Hg 4 11

*We assume that point boilers are a surrogate for major boilers and non

- point boilers are a surrogate

for area boilers. However, some boilers affected by the Boiler MACT for major sources are in the non

point inventory in the NEI.