inventory, emissions, and population

FINAL 1

Inventory, Emissions, and Population

July 2, 2003

AIR, Inc.

FINAL 2

Overview

• Exhaust Emissions

• Evaporative Emissions

• Populations

FINAL 3

Materials Received/Utilized from ARB

Population and Activity Memo April 14Hot soak RVP data April 15Evaporative Spreadsheets (preliminary) April 17Evaporative Emissions Memo April 21Tier 3 Exhaust Emission Factors May 1Lifetime emissions and cost effectiveness June 5Equipment Survey Data June 8Total inventories June 26Cost effectiveness model/assumptions June 30Inventories split by exhaust vs evaporative July 1Audit data analysis ??

FINAL 4

Exhaust Emissions

• Major comment is that the baseline does not reflect the Premium Program– baseline is used to determine cost effectiveness of proposed Tier 3

exhaust standards

FINAL 5

Premium Program

• What is it?

• Performance

• OFFROAD assumptions

• Lifetime emission impacts

• Summary

FINAL 6

What is it?

• 1999 exhaust proposal included Tier 2 and Tier 3– Tier 2 implemented in 2000, Tier 3 was to be implemented in 2004

• Final rule included Tier 2 and Premium Program– Premium Program covered the emission reductions of Tier 3

– Briggs and Stratton and Tecumseh were participants

FINAL 7

2002 Class 1 Engine Exhaust HC + NOx

0.00

2.00

4.00

6.00

8.00

10.00

12.00

Zero Hour Useful Life

HC

+ N

Ox

Preliminary Industry-Wide Estimate

ARB Emission Factor

FINAL 8

2002 Class 2 Engine Exhaust HC + NOx

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

Zero Hour Useful Life

HC

+ N

Ox

Preliminary Industry-Wide Estimate

ARB Emission Factor

FINAL 9

Premium Program

• Data show 2002 emissions lower than assumed in some analyses

FINAL 10

OFFROAD Model

• Also does not include the effects of the Premium Program– Districts have not been able to book these reductions

FINAL 11

Tier 3 Lifetime HC + NOx Reductions Per Unit (lbs)

Equipment Without PremiumProgram

With PremiumProgram

Lawnmower 3.1 2.4

Commercial Turf 280.3 238.7

*AIR estimates of emission reductions for both cases

FINAL 12

Tier 3 Exhaust Cost Effectiveness

• Residential Lawnmower

• Assumes ARB standards implemented as proposed

• Exhaust cost increase: $54 (Briggs and Stratton)

• Preliminary estimate: $44,000 per ton of HC+NOx

FINAL 13

Summary - Exhaust Emissions

• ARB should revise its Tier 2 baseline for estimating proposed Tier 3 cost effectiveness

• OFFROAD model should be revised

FINAL 14

Evaporative Emissions

• Concerns:– Baseline and control diurnal and resting losses overestimated

– Baseline running loss deterioration too high

– RVP effect for hot soak and running losses too large

– Running loss reductions depend on technology used

FINAL 15

Diurnal and Resting Losses

• ARB definition of evap processes in OFFROAD model: they cannot overlap

• However, for ARB’s lifetime emission reductions and cost-effectiveness, they do overlap (“partial” diurnals)

• This results in some double-counting of emissions

• This will be addressed in soon-to-be released OFFROAD model, but is not yet addressed in ARB’s lifetime emissions, inventories, or cost/effectiveness– Small effect for residential equipment, significant for commercial

– Could not address magnitude of this effect for workshop

FINAL 16

Running Loss Deterioration

• Diurnal, resting loss and hot soak emissions for lawnmowers estimated on 23 lawnmowers– New, Used, Old

• Running losses estimated on only 4 lawnmowers

• Running loss deterioration not consistent with other evap components– One Alternative: use deterioration on other components to predict

running loss deterioration

• Similar concern for other equipment

FINAL 17

Ratio of Lawnmower Emissions at Different Ages to Emissions at Zero Hour

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

Diurnal Resting Hot Soak Running

Evap Component

Rat

io o

f E

mis

sio

ns

Zero Hour

Used

Old

FINAL 18

Hot Soak and Running Loss RVP Effect

• ARB developed RVP effect at 95F and is applying it at all temperatures

• Annual RVP assumed (8.1) may not reflect seasonal activity differences

• RVP does not have same effect at all temperatures• Increases baseline and controlled emissions by same

percentage (25%), so benefit of controls is also larger• One alternative is to eliminate this effect

FINAL 19

Running Loss Reductions

• ARB estimated at 50%– test data indicates 42%

• New lawnmower percent reduction will not apply when equipment older– Should use g/hr reduction on new engines at all ages

• Also, reductions depend on control technology used– Pressurized system with TPCV only gets permeation benefit,

because pressure controls have to be “open” when engine running

– Canister controls would get permeation + vapor benefit, since canister is connected to tank during engine operation - no data

FINAL 20

Baseline Evaporative HC Lifetime Emissions Per Unit (lbs)

Lawnmower(Class 1)

Commercial Turf(Class 2)

Current Approach 17.5 71.6

With modifiedrunning lossdeterioration

15.1 48.8

Without RVPeffect

14.3 41.3

FINAL 21

Tier 3 Evap HC Reductions Per Unit (lbs)

Lawnmower(Class 1)

Commercial Turf(Class 2)

Current 12.1 42.8

Revised 9.9 24.3

Revised: ARB method and assumptions, and includes changes to baseline, and smallerrunning loss reduction

FINAL 22

Population and Activity

• Evaluated population and activity changes

• Why discuss this?– Population/activityinventoriestargets for alternatives

– Activityproportion of evap vs exhaust

• Concern– Populations must be consistent with Census data

FINAL 23

Populations

• ARB conducted equipment survey

• Survey is being used to update populations

• Large proposed changes in populations– Lawnmowers: 2.4 million to 4 million

– Chainsaws: 0.6 million to 2.1 million

– Trimmers/edgers: 0.8 million to 2.8 million

• Inventories based on these new populations appear in the SCAQMD SIP

FINAL 24

Survey and Method

• 15,000 surveys sent– 2200 responded to survey (<15%)

– 220 agreed to use data loggers (<2%)

• Equipment populations were determined in the 2200 households

• Total California households were determined: 11.5 million

• Popstate = Popsuvey x 11.5 million/2200

• Problem: Survey overweighted single detached residences, which have a higher equipment ownership

FINAL 25

Fraction of Residence Types

Type ARB Survey 2000 Census, California

Single, detached 80% 57%

Single, attached 4% 8%

Multiple 12% 31%

Mobile Home 3% 3%

Boat, van, RV 1% 1%

FINAL 26

Equipment Per Residence

Residence Ratio, Equipment to Residences

Single, detached 1.07

Single, attached 0.07

Multiple 0.07

Mobile home 0.67

Boat/RV 0.67

FINAL 27

Survey

• These tables indicate that sample must be re-weighted by Census residence type fractions

• This will have a significant effect on populations, and therefore, inventories

FINAL 28

Summary - Population

• ARB proposed populations should be revised to match Census residence demographics

FINAL 29

Summary

• Exhaust– Tier 2 baseline emissions should include Premium Program

• Evaporative– Size of inventory and reductions uncertain

• Population– Too high