South Coast 

r Quality Management District 

Copley Drive, Diamond Bar, CA 91765-4178 

• ._ .. ,:·(•"'"'"''""""''"'-L.'"""""' • www.aqmd.gov 

Mining Association 

Malcolm C. Weiss, Esq. 

Jeffer, Mangels, Butler & Marrnaro, LLP 

1900 A venue of the Stars 

Seventh Floor 

Los Angeles, California 90067 

Office of the Executive Officer 

909-396-2100 

December 15, 2006 

Subject: Rule 1157- PM10 Emission Reductions from Aggregate and Related Operations 

Dear Mr. Weiss: 

Pursuant to the settlement agreement between CMA and AQMD, the Rule 1157 emissions 

inventory has been re-examined. On December l, 2006, the AQMD Governing Board ratified a 

revised emissions inventory after an open and public review process (Attachment 1). 

The revised emission factors and asswnptions used as the basis for the new inventory 

(Attachment 2) will be employed for all future purposes until a new emissions inventory is 

approved by the Governing Board. These future purposes include internal and external 

commUnications, CEQA review and permitting analyses, as well as the Air Quality Management 

· Plan and the Annual Emissions Reporting program. 

If you have any questions, please contact me at (909) 3 96-3131 or Laki Tisopulos, Assistant 

Deputy Executive Officer, at (909) 396-3123. 

cc: Elaine Chang 

Carol Coy 

Mohsen Nazemi 

Laki Tisopulos 

Kurt Wiese 

BRW:LT:LL:TG 

Sincerely, 

Barry R. rstein, D.Env. 

Executive Officer 
Attachment 1 
Soutl1-Coast 

Air Quality Management District 

21865 Copley Drive, Diamond Bar, CA 91765-4178 

(909) 396-2000 · http://www.aqmd.gov 

BOARD MEETING DATE: December 1, 2006 AGENDA NO. 15 

PROPOSAL: 

SYNOPSIS: 

COMMITIEE: 

Ratify Revised Emissions Inventory for Adopted Rule 1157 -

PM10 Emission Reductions from Aggregate and Related 

Operations 

Rule 1157 was adopted by the Board in January 2005. The Board 

directed staff to work with industry to re-examine the emissions 

inventory for the adopted rule. Although still significantly higher 

(eleven fold) than the inventory used for the 2003 AQMP control 

measure (BCM-08), the revised inventory reflects an approximate 

50 percent decrease from the pre- and post-rule calculated 

emissions inventories, as included in the staff report for Rule 1157. 

The revised assumptions and methodologies will be used in all 

future emission calculations for permitting, CEQA, and annual 

emissions reporting purposes. 

Stationary Source, November 17, 2006, Reviewed 

RECOMMENDED ACTION: 

Receive and ratify" the attached revised emissions inventory and authorize the Executive 

Officer to provide a letter to the California Mining Association acknowledging this 

revision. 

Barry R. Wallerstein, 

~-~ D .Env. 

Executive Officer 

EC:LT:U:TG 

Introduction 

Rule 1157 was adopted on January 7, 2005 to further reduce particulate (PMlO) 

.emissions from aggregate and related operations as part of the 2003 AQMP Control 

Measure BCM-08 -Further Emission Reductions from Aggregate and Cement 

ManUfacturing Operations. During the public hearing for adoption of Rule 1157, some 
members of the aggregate industry raised concerns regarding. the methodology for 

estimating the PMIO emissions inventory presented in the staff report, particularly as 

related to emission factors and assumptions (e.g., throughput). West Coast 

Environmental and Engineering (WCE) submitted a written report on behalf of the 

Southern California Rock Products Association (SCRPA) analyzing the emissions 

inventory developed by AQMD staff and expressing their strong disagreement with 

staff's analysis. 

In the'adopting resolution, .the Board directed staff to "include a review of the emissions 

inventory for Proposed Rule 1157 ... in the development work for the AQMP and that 

any necessary revisions be incorporated into the baseline emissions inventory for the 

AQMP." 

On February 10,2005, the California Mining Association (CMA) filed a lawsuit against 

the AQMD alleging, among other claims, that the rule was based on a ''flawed emissions 

inventory." On September 2, 2005, CMA and the AQMD executed a formal settlement 

agreement. As part of the settlement agreement, the AQMD acknowledged, in 

conjunction with the aforementioned Board direction, that a review of the data and 

methodologies used to derive the inventory was warranted. Since that time, staff and 

indllitly have met on numerous occasions to arrive at a mutually acceptable inventory. 

Background 

Following the Board directiou to review the enrissio~ inventory, staff carefully 

evaluated WCE' s report, and began working with SCRP A and WCE representatives to 

review issues related to the emissions inventory development · 

AQMD staff met with representatives of SCRP A and WCE on more than a dozen 

occasiol).S to reexamine the development of the emissions inventory. This includes . 

assumptions used and· survey data provided by industry during rule development that 

staff used for developing the PM1 0 emissions inventory. As a result of these meetings, 

staff made adjustments to the ·PMl 0 emissions inventory based on best available 

scientific and supportive docwnentation that staff gathered. Not all areas unde~ dispute 

were mutually resolved; however, sufficient progress was made such that an adjusted 

emissions inventory was eventually completed. 

Methodology for Developing the Initial PMIO EmisSionS Inventory 

During the development of Rule 1157, AQMD staff conducted a survey of ~gate 

and related facilities using survey forms that were developed with approval from 

industry including SCRP A/SCRMA (Southern Califoinia Ready Mixed Concrete 

Associatiol).). The purpose of the survey was to refine the emissions ~vent:Qry listed in 

fPe 1997. AQMP for these SOUrce categories. Data collected from the survey was useQ 

for the following: , · · · · 

'l. 
• identify and characterize facilities subject to the proposed rule; 

• estimate PMIO emissions generated by these facilities; and 

• establish the baseline PMIO emissions for this industry in the air basin. 

Staff used the information provided by the SCRP A and SCRMA, data obtained from the 

AQMD permit system and the 2001-02 Annual Emissions Reporting (AER) database to 

identify 395 potential survey respondents. 

The survey forms were distributed in March 2004. Based on the survey results and 

additional input from the industry, staff estimated the number of aggregate and related 

facilities in the air basin by category, summarized as follows: 

Aggregate and Related Facilities in the South Coast Basin 

Aggregate 29 

Concrete Batching 100 

Concrete Product 152 

Crushed Miscellaneous Base 25 

Hot Mix Asphalt 45 

"Other" 38 

Total 389 

Additionally, staff estimated PM10 emissions for each facility and category based on 

inputs provided by the facilities participating in the survey. Emissions for each facility 

are classified into three main emission sources: process equipment, stockpiles, and road 

·(paved/unpaved) emissions. PM10 emissions from process equipment include 

emissions generated from loading and unloading activity, hoppers and surge bins, 

conveyor transfer points, crushers, screens, milling equipment, and truck load..auts. 

The survey-based average PMlO emissions generated for each category were then scaled 

up to estimate the baseline emissions fuvento.ry for the entire aggregate industry and 

related operations. Staff used only data from dry aggregate materials to calculate PMIO 

emissions for each applicable activity, equipment, and/or emission source (i.e., 

loading/unloading, hopper/surge bin, conveyor transfer point, crushing, screening, 

- 3-
milling, silo, cement truck loading, HMA load-<>ut, open storage pile, unpaved roads, 

and track-out). 

The pre- and post-rule emissions inventories were calculated to be approximately 29 

and 11 tOns per day, respectively, for an overall rule effectiveness of62%. The pre-rule 

emissions inventory is in significant contrast to that used in the 2003 AQMP control 

measure, which set the inventory for aggregate processing at 1.2 tons per day. 

Findings 

As mentioned earlier, staff met with the SCRP A and WCE representatives on numerous 

occasions to discuss the methodologies and assumptions used in developing the PM1 0 

emissions inventory. All aspects of the emissions inventory, such as development of the 

assumptions, interpretation of the survey data., selection of the emission factors, and 

formulas used for estimating emissions have been carefully re-evaluated by industry 

representatives and staff. The following summarizes the key issues. pertaining to the 

development of the ·PMl 0 emissions inventory. 

Areas of Agreement/Resolved Issues 

• Proper use of throughput for calculating process emissions. 

•: Post-rule control efficiency of water at 95%. 

• _No crushing of fine materials. 

• Fly ash and cement throughput were used to calculate cement truck loading 

emissions. 

• Haul truck capacity of 75 tons used to determine roadway emissions. 

• Silt loading for uncontrolled paved roads. 

• Use of 80% control efficiency for unpaved roads treated with chemical dust 

suppressants. 

• · Credit given in calculations for pre-rule compliance with Rule 403 and appropriate 

federal New Source Performance Standards (NSPS) provisions. 

• Fines screening of 20%. 

• Facility-specific data only relea8ed for facilities waiVitig confidentiality of data. 

.Areas of Disagreement/Unresolved Issues 

• Basis fot ~ general pre-rule controJ efficiency of water of 50%, supported by 

compliance hi$00ry of issued Notices of Violation. 

• Moisture .content used as a proportional measurement to control efficiency. 

• Calculation method of stockpile emissions (tons throughput vs. acre-day emissions 

factors). 

• Confidentiality of individual survey fonns for all. reSponding facilities (non-CMA. members). · 

A 

( 
Revised PMlO Emissions Inventories and Assumptions 7 A. Pre-Rule 

As stated earlier, baseline (pre-rule) PM10 emissions for the aggregate and related 

operations were estimated to be 29 tons per day (Rule 1157 Staff Report, December 3, 

· 2004 ). It should be noted that industry representatives provided valuable additional 

information that assisted in refining certain key asswnptions. The revised PMIO 

baseline emissions inventory is now estimated to be 13.7 tons per day, which representS 

a 53% decline f:rom the adopted Rule 1157 emissions inventory. The increase in the 

current level of pre-rule control from 20% to 50% and other revised assumptions 

resulted in lower PM10 baseline emissions for process equipment, open piles/storage, 

and unpaved roads. However, baseline emissions from paved roads increased because it 

was agreed that emissions from these roads have been essentially uncontrolled up to the 

time that the rule was adopted. 

B. Post-Rule 

For PMIO emission reduction calculations (post-rule), staff has agreed to assign a 95% 

control efficiency to water application based on the assumption that the industry will 

strictly adhere to the PMIO control requirements of Rule 1157. Using the revised PMIO 

baseline emissions, staff recalculated the PMIO emission reductions for each PM10 

emission source. The revised total PMlO emission reduction is now 5.7 tons per day 

based on the revised baseline versus 18 tons per day reduction as reported in the Staff 

Report for Ru1e 1157. The remaining inventory with full implementation of Rule 1157 

is now 5.3 tons per day (versus II tons per day as reported in the Staff Report for Rule 

1I57). 

· The final revised pre-and post-Rule 1157 emissions inventories were sent to CMA 

representatives on October 6, 2006. A letter of response from CMA dated October 17, 

2006 indicated that CMA has agreed to ·the revised pre-and pos~rule emissions 

inventories presented by staff, notwithstanding the remaining areas of disagreement. 

CMA recognized the significant progress in refining the emissions inventory and the 

<:fevelopment of a better working relationship as both parties continue to work on other 

areas of the settlement agreement. It should be noted that CMA' s calculations put the 

pre- and post-rule emissions for the industry at less than half that of staff's calculations. 

Figure A provides a summary of the emissions from this industry assumed in the 2003 · 

AQMP, the baseline and post-rule implementation remaining emissions included in the 

December 2004 Staff Report, and the revised baseline and remaining emissions, which 

will be incorporated into the 2007 AQMP. 

-5-
i -

35 

>- as 30 

a 

... 25 

:. 20 

(I) 15 c:: 

0 

1- 10 

5 

0 

Figure A: Rule 1157 Revised Inventory Comparison 

2003AQMP 2004 Staff 

(BCM-08) Report 

Revised 

Inventory 

•Pre-Rule 

• Post-Rule 

Appendix A shows a comparison of the revised PMIO baseline emissions and remaining 

PMl 0 emissions by category with those presented in the December 2004 Staff Report. 

Attachments 

A-1. Comparison of PMlO Baseline Emissions (Pre-Rule 1157 Inventory) 

A-2. Comparison of PMlO Remaining Enussions (Post-Rule 1157Inventory) 

- 6 -
Appendix A 

Table A-1 Comparison of PM10 Baseline Emissions (Pre-Rule 1157 Inventory) 

gg g I 6.40 I 1.25 

I 

1.70 I 0.95 I 8.33 I 3.97 I 0.27 I 1.43 I 16.70 I 7.60 

Concrete 

Batching I 2.90 I 0.35 

I 

0.10 I 0.05 I o.12 I 0.06 I o.o8 I 0.24 I 3.2o I 0.70 

Hot Mix 

Asphalt 

1

1.20 I 0.93 I 0.90 I 0.58 I o.25 I 0.12 I 0.25 I 1.27 I 2.60 I 2.90 

Concrete 

Products I 3.50 I 0.64 I 0.52 I 0.32 I o.o3 I 0.01 I 0.07 I 0.13 I 4.12 I 1.10 

Crushed Misc. 

Base 0.20 0.05 0.20 0.12 0.03 0.01 0.01 0.05 0.44 0.24 

Other 0.03 0.02 1.90 1.08 0.00 0.00 0.03 0.05 1.96 1.15 

TOTAL I 14.23 3.24 5.32 3.10 8.76 4.17 0.71 3.17 29.02 13.68 

Note: Some line-item totals may not sum exactly due to numerical rounding. 

A- 1 
Appendix A (continued) 

Table A-2 Comparison of PM10 Remaining Emissions (Post-Rule 1157 Inventory) 

99 9 

1

1.69 I 0.16 

I 0.84 I 

0.1 0 

I 2.16 I 

2.33 I 0.07 I 0.57 I 4.76 I 3.16 

Concrete 

Batchin9 I 2.57 I 0.25 I 0.03 I 0.02 I 0.02 I 0.02 I o.o2 I 0.10 I 2.64 I 0.39 

Hot Mix 

Asphalt I o.18 I 0.75 I o.47 I 0.06 I o.o1 I 0.05 I o.o6 I 0.51 I 1.38 I 1.37 

Concrete 

Products I o.81 I 0.10 I o.28 I 0.05 I o.o1 I 0.00 I o.o2 I 0.05 I 1.12 I 0.20 

Crushed Misc. 

Base 0.05 0.01 0.10 0.01 0.01 0.00 0.00 0.02 0.16 0.04 

Other 0.02 0.00 0.87 0.11 0.00 0.00 0.01 0.02 0.90 0.13 

TOTAL 5.92 1.27 2.59 0.34 2.27 2.41 0.18 1.27 10.96 5.29 

Note: Some line-item totals may not sum exactly due to numerical rounding. 

A -2 
Attachment 2 
Comparison of Assumptions for PM10 Baseline Emissions 

~·"- >Wkm ::c:;c;ousen ' ;. ; _ QCA!;J44 .......-- ...,.~f'.__. 'F --~ ~ '""' ~'~ - - ..-~ J!...... 

· """"""* ' ~~ ~ 1 

·-~w h-- w ' " '•, "h~ · , 

":\,~ • ..,•IJliW .. •. . ._ . <l nl u~..: Acuv ny 

lrrr .... d ~~:• :· '"ro11phr11t d<1ta (sur-.·r:') 

For Aggregate/CMB: 

E = (Annual throughput x 2 x 

EF I 2000) x CF 

For CBIHMA/CP/Others: 

E = (Annual throughput x 

EF 12000) x CF 

where: 

E = PM10 emissions, tons/yr 

EF = PM10 emission factor, 

lbs/ton 

CF = control factor 

= 1-control efficiency (CE) 

Note: 

For Aggregate/CMBIHMA: 

• EF aggr .==0 .0011 lb/ton (AP-42) 

For CB/ CP/Others: 

• Staff assumed throughput 

composition of 50% aggregate 

l\lld 50% sand (from San Diego 

APCD) 

• EF aggr.==0.0033 lbs/ton 

(AP-42) 

EF sand=0.00099 lbs/ton 

(AP-42) 

CE wllte1(cutTent level) r:: 20% based on the following: 

• 75% of aggregate facilities use water for control 

(survey data) 

• assume water is used <30% of time based on 

field observations 

Post Rule 1157 CE water= 60% 

Usrd nn ~IJ l throughput from survey. 

Adjusted throughput accordingly to composition. 

For Aggregate/CMBIHMA: 

• EF aggr, uncontrolled.=O.OOll lb/ton (AP-42) 

ForCB: 

• Throughput composition: assumed 41 o/o dry 

aggregate (112 of82% total aggr.) 

• EF aggr., uncontrolled=0.0033 lb/ton (AP-42) 

For CP/Others: 

• Throughput composition: assumed 50% 

aggregate and 50% sand (San Diego APCD) 

• EF aggr., uncontrolled=0.0033 lb/ton (AP-42) 

• EF sand, uncontrolled=0.00099 lb/ton (AP-42) 

ForHMA: 

• Throughput composition: assumed 92% 

aggregate 

CE w.m- (current level) - SO% based on the 

following assumptions: 

• 75% of aggr. fac. use water for control (survey 

data) 

• Water is used 65% of the time (survey data , 

permit conditions, NOVs/NCs, & field 

observations) 

Post Rule 1157 CE water-= 95%·(AP-42 and 

AOMD Emtineerin~) 

Aggr. = Aggregate CB ""' Concrete Batching 

HMA = Hot Mix Asphalt 

CMB = Crushed Miscellaneous Base 

CP = Concrete Product 

Page 1 
Comparison of Assumptions for PM10 Baseline Emissions 

, ..... ,.;:~_ ..... ,.:.,. ~- -· • .. ", '"' .. ·., .. :;...;.-:- ~"- ........ . : ;.-;- ~, ·£.L'Si ..... ~--• .. . ,. -:::;~-l~ :-.. :-:\~-~'!~~- : -~,'$-:.~·-~.· .::_ ·":.:: · . .. :' . .. :;···.:-.. _;;.~ ~"""~""'·';i,~~: "';&'~~· .... -.¥·;(' ·;;-."1.-',~ ..... ~~ •. '"·:.iv'~·- :;sf:~i'· ~·- ;;. 4.1·. •· ..... : . .,;,;, ·::·< ••••. . ,,.,·.,. . •. ·,;.,.~ •• .:·· .t;,~ ;:.::~£~);. .:lt:")'_:_ ,~t?) .. ~~:-: .,~~7~;&~~~ :.-r.~~" ~~~~~ ~~~~~-~-4-~·~,:.,.. ~~·:/~::: ~t;':~T: ~·=~-· ~ 0 • • - ""· ~~ .';,~~ 

E = (Hourly throughput x annual operating 

hrs X EF/2000) X CF 

where: 

E = PM10 e!l1issions, tons/yr 

EF = PM10 emission factor, 

lbs/ton 

CF = control factor = 1- control efficiency (CE) 

Note: 

Used hourly throughput data (survey) 

Same emission factors and assumptions as in 

Loading/Unloading activity 

Used hourly throughput data from survey 

Annual operating hours = annual throughput I 

plant capacity 

Used same pre-rule and post-rule CE as in 

Loading/Unloading activity 

For Aggr/CMBIHMA: 

• Used same emission factor as in 

Loading/Unloading activity (0.0011 lb/t) 

ForCB: 

• EF uaconii'Oikd = 0.0024 lb/ton (AP-42) 

For CP/Others: 

• Used same assumptions and EFs as in 

Loading/Unloading activity. 

Aggr. = Aggregate CB : Concrete Batching 

HMA ==Hot Mix Asphalt 

CMB = Crushed Miscellaneous Base 

CP = Concrete Product 

Page2 
Com~arison of Assumptions for PM1o Baseline Emissions 

~. ·· ... r>~·.l,lr·· J' ·;: '.;·: c.·. ~ .... '"'>:-J:X .• ~~ ., .. < ,:.·· 'J ... 1;,:.;,. '• -~· .;,:.,__. .. :, ~ ·:./::': ~- ;>: :'t, --.- !\ ·::~. <:;. -~~·<''.-A;;~~-~~j. ~;;~·~/~:- :<}j ;):~~"=~: .. ~:~~- ~i. •. ' u:..~i:;: •!t1l'\-..., .... _." "''"''"·'··· <--":':'•'-:-""\"et.~"• .'~"' ·"''''•<"'" <;:.·• -•J!;Z~~-- .· t,, '···~·~· ~-' ~, , .. •'··~';,1~· ~r,;;&. ~-. ~ • ~ ,-.,.·~ .' ...,, , ~< ';. " "-' •• ~ • • ~ ·- .. • •• ....., ~ ··'•' ...... . --."-"'..:!' ••• - .. "';~- .. "·c.~: .. ..... , . .- :t."•l~t~· '! ' \. \ '"h' ... J .... ':::_.V• ~>.f~~ "'~· ·tj,)~~· .. "" ~ ~ ·- .'1...,.: .. ,·1'::"' _ -... 1.::. ... ·:..~, _ ... ~ \ · ... ,·.;.I-;~~ ,> :- .. 2'-.:f. ·!L..~ 'l--':.Z~'1or~· ... ~~·;;..f.:-.v ·.: J!r.r~li~i;:<ftJ~~-8""--~ ~-;;x .... "' ;~ :---=--.. ;?:)! }'Y ~~ \.~ ·rr -:.~ ~~·~,.-~ ·• w..-.. .... . .. ...:. - • ·.~·-·- ' :;.,., ~J '-.!....t' .....:;..,."i"" w, t.. '-"":_ ,,....;~:J-. . ~~ ~_':lo ::.z.!..,.;,.;..~ .. ~w'--:..n ' ~ ~ -->.N · '!:;: ,.,. "?" .... '.-:;"" ..... .-.;- ,, <Tol; 

E = (Hourly throughput x annual operating 

hrs X EF /2000) X CF X N 

where: 

E = PM10 emissions, tonslyr 

EF = PM10 emission factor, 

Ibslton 

CF = control factor 

= I - control efficiency (CE) 

N =number of transfer points 

Note: 

Used hourly throughput data (survey) 

For Aggr JCMBIHMA/CP/Others: 

• Same emission factors and assumptions as in 

Loading/Unloading activity 

ForCB: 

• EF=0.0024 lb/ton (AP-42) 

Used hourly throughput data (survey). Adjusted 

throughput accordingly to composition. 

Annual operating hours = annual throughput I 

plant capacity 

Used same pre-rule and post-rule CE as in 

Loading/Unloading activity 

For Aggr.ICMB/HMA: 

• Same emission factor (0.001 1 lb/t) as in 

LoadinEitJnloading activity 

ForCB: 

• Assumed throughput 

composition of 50% aggregate & only 

aggregates are transported by conveyors 

• EF a&v.·· UIICOIIUOilcd= 0.0033 lbs/ton 

(AP-42) 

For CP/Others: 

• Used same assumptions and EFs as in 

Loading/Unloading activity. 

Aggr. =Aggregate CB = Concrete Batching 

HMA =Hot Mix Asphalt 

CMB = Crushed Miscellaneous Base 

CP - Concrete Product 

Page 3 
Comparison of Assumptions for PM10 Baseline Emissions 

E = (Hourly throughput x annual operating 

hrs X EF/2000) X CF 

where: 

E = PM10 emissions, tonslyr EF = PM10:emission factor, 

lbslton 

CF = control factor = 1 -control efficiency~CE) 

Note: 

Used hourly throughput data (survey) 

For Aggregate/CMB/HMA: 

• Assume 50% tertiary crushing and 50% fines 

crushing 

• Assume BACT requirements are met (baghouse) 

• EF reniory,conuoued=0.00054 lbs/ton (AP-42) 

• EF rllles,cODrrolled=O.OOl2 lbslton (AP-42) 

ForCP: 

• Assumed that crushers meet BACT requirements 

EF autber.con~rollc.t=0.00059 lbslton (AP-42 

Used hourly throughput data (survey). Adjusted 

throughput accordingly to composition. 

Annual operating hours = annual throughput I 

plant capacity 

Based on industry input, only 20% of total 

material throughput is processed by primary 

crushers; the rest is either processed by secondary 

and/or tertiary crushers 

For Aggr./CMBIHMA: 

• No fine crushing (industry input) 

• EF terti"!)'. unconrrolled = 0.0024 lb/ton (AP-42) 

• 30% ot facilities use water at 65% of the time 

& 70% use baghouse for control (survey data) 

• CE..aser= 95% 

• CEba~=99% 

• Pre-rule overall CE: 

(30% X 95% X 65%) + (70% X 99%) = 87.8% 

(This is higher than the 77.5% CE for tertiary 

crushing in AP-42) 

• PosHule CE: 

(30% X 95%) + (70% X 99%) = 97.8% 

ForCP: 

• Same assumption and emission factor as in 

staff report EFcrushet,concrolled = 0.00059 lbslton (AP-42) 

Aggr. =Aggregate CB = Concrete Batching 

HMA = Hot Mix Asphalt 

CMB = Crushed Miscellaneous Base 

CP • Concrete Product 

Page4 
Comparison of Assumptions for PM to Baseline Emissions 

EMISSION SOURCE STAFF RiPORT REVISED STAFF REPORT 

Screening Equipment 

E = (Hourly throughput x annual operating 

Used hourly throughput data (survey) Used hourly throughput data (survey). Adjusted 

throughput accordingly to composition. 

hrs X EF/2000) X CF 

where: 

Annual operating hours = annual throughput I 

plant capacity 

E = PM1o emissions, tons/yr 

EF -= PM1o emission factor, 

lbs/ton For Aggr./CMB: For Aggr./CMB: 

CF ==control factor • assume 50% fine screening and SO% coarse • Assumed 20% fme screening and 80% coarse 

== 1 - control efficiency (CE) screening screening (industry input) 

• EF coarse,WICO"tronect=0.0087 lbslton (AP-42 • EF coartC, uncontrolled= 0.0087 lb/ton (AP-42 

• EF fines.un~ontronect=0 072 lbs/ton (AP-42) • I:;F r~nu. uncontrolled= 0.072 lb/ton (AP-42) 

• CE: assume SO% based on current level of • 7S% of facilities use water at 6S% of the time 

watering/misting observed & 2S% use baghouse for c~mtrol (survey data) 

• CE-tcr=9S% 

• CEI>aaho-=99% 

• Pre-rule overall CE: 

• 

(75% X 95% X 65%) + (25% X 99%) = 71.1% 

Post-rule CE: 

(75% X 95%) + (25% X 990/o) =·96.1% 

ForCP: ForCP: 

• EF-ne.r=O.S3 lb/ton (AP-42) • EFuncoDUO\Ie<l= ().53 lb/ton (AP-42 

• CE: assume SO% based on 

current level of watering/misting observed • Same pre-rule (71.1%) and post-rule (96.1%) 

CEs as Aggr./CMB 

ForHMA: ForHMA: 

Assume 100% controlled • Assumed that only RAP (recycled· aggregates) 

EF-11ecf"0.0098 lb/ton (AP-42) are screened with this equipment 

• EF c.ovK. .-o11e4- 0.0087 lb/ton (AP-42 

• Same pre-rule (71.1%) and post-rule (96.1%) 

CEs as Aggr JCMB 

Aggr. = Aggregate CB = Concrete Batching CMB = Crushed Miscellaneous Base CP "' Concrete Product HMA = Hot Mix Asphalt 

Page5 
Comparison o_f Assumptions for PM10 Baseline Emissions 

E = Hourly throughput x annual operating hrs 

X EF /2000 

where: 

E = PM10 emissions, tons/yr 

EF = PM10 emission factor, lbslton 

• Assume all milling equipment are controlled 

• EFcontrotled = 0.0032 lb/ton (AP-42) 

Used hourly throughput data (survey) 

Annual operating hours = annual throughput I 

plant capacity 

Same assumption/emission factor as in staff report 

E = Silo annual throughput x EF I 2000 

where: 

• Assume 85% ofthroughput is cement and 15% is 

fly ash 

Used silo throughput from survey 

E = PM 1o emissions, tons/yr 

EF = PM10 emission factor, lbs/ton 

E = Annual throughput x EF I 2000 

where: 

E = PMto emissions, tons/yr 

EF = PM10 emission factor, 

lbs/ton 

Note: 

• Assume all silos are controlled (baghouse) 

• EFcemen~> ~lllrolled= 0.00034lb/ton (AP-42) 

• EFoyuh.coatroUed= 0.00491b/ton (AP-42) 

• EF contro1te.t = 0.051 lb/ton (AP-42 

Aggr. =Aggregate CB = Concrete Batching CMB = Crushed Miscellaneous Base 

Page6 

Adjusted throughput accordingly to same 

composition assumptions as in staff report. 

Used same emissio~ factors as in staff report 

Used annual throughput from survey. Adjusted 

throughput accordingly to composition. 

ForCB: 

• Assumed throughput composition of 12% 

cement + 2% admixture 

Same emission factor as in staff report 

CP = Concrete Product HMA = Hot Mix Asphalt 
Comparison of Assumptions for PM to Baseline Emissions 

A~!)llall L vliU- UU ( 

E =(Annual throughput x EF) /2000 

where: 

E = PM10 emissions, tons/yr 

EF = PM10 emission factor, 

lbs/ton 

where: 

E = PM10 emissions, tons/yr 

EF = PM10 emission factor, 

lbs/ton 

CF = control factor 

= 1-control efficiency (CE) 

E = Hourly throughput X annual operating hrs 

xEF / 2000 

where: 

E = PM1o emissions, tons/yr 

EF'"' PM10 emission factor, lbs/ton 

Note: 

• EFPM. cootrolled = 0.0003 lb/ton (AP-42) 

• EFPMIO, conlrolled = 0.5 X EFPM.COIIIrOlled 

• EFPM. IIIIControlle<f = 0.33 lb/ton (AP- 42) 

• EFPMIO, IUICOIUrolled = 0.5 X EFPM. unc:ont 

• CE water (current level)= 20% 

• CE water (post 1157) = 60% 

Did not separate amount of aggregates to be screened 

by different equipment 

Used annual throughput from survey 

Used same emission factor as in staff report 

• Same emissions factors as in staff report 

• CE water (current level)= 50% 

• CE water (post 1157) = 95% 

Note: AP-42 allows the use of either surface area 

EF or material weight EF 

ForHMA: 

• Used hourly rate in the survey 

• Annual operating hours = annual throughput I 

plant capacity 

• Assumed that all aggregates are processed by 

this equipment 

• EF PMIO, COftiiOtleC 0.027 lb/t (AP-42) 

Aggr. = Aggregate CB = Concrete Batching CMB = Crushed Miscellaneous Base CP = Concrete Product HMA = Hot Mix Asphalt. 

Page7 
E = VMT X k X (S/ 12)1 X (W/3)b 

where: 

E = PMao emissions, tonslyr 

VMT = annual vehicle miles 

traveled 

k,a,b = constants 

k = 1.5 lbs/VMT (AP-42) 

a= 0.9 (AP-42) 

b = 0.45 (AP-42) 

S = surface material silt content 

in% 

W = mean vehicle weight in tons 

Note: 

Comparison of Assumptions for PM1o Baseline Emissions 

VMT =(road length (ft) x #truck trips/day x # 

days/yr) x l mile I 5280 ft 

Assumed that W unla.cled btu! cruck .. 1 OOt, W a-~ed baultru<Jc 

= 150 t, W W\lo..scd ~truck= 5 t, and 

W lo.ded 110ft-haul cruck = 30 t (industry's input). 

Assumed that 50% of the vehicles were loaded and 

50% were unloaded 

For aggregate facilities: 

• SHaul roed = 8.3% (AP-42) 

• SNoo-haulroad = 10% (AP-42) 

For other facilities: 

• SIUul-.t = 7.1% (AP-42) 

• SNOftolwalroed = 4.8% (AP-42) 

Assumed CE for chemical stabilizer = 80% 

VMT = (road length (ft) x # truck trips/yr x l mile 

/ 5280 ft 

• # truck trip/yr = annual throughput I truck 

capacity 

• Assumed truck capacity: 75 tons 

Assumed that W unloaded haul cruck= 45 t, W loaded ...... 

cruck=120 t, based on most popular size truck 

Assumed same weights of non-haul trucks as in 

staff report 

Assumed that 50% of the vehicles were loaded and 

50% were unloaded 

Assumed same silt content values as in staff report 

Pre-rule CE for water = 50% 

Assumed pre & post-rule CE for chemical 

stabilizer = 80% 

Aggr. = Aggregat~ · CB = Concrete Batching CMB = Crushed Miscellaneous Base CP = Concrete Product HMA c Hot Mix Asphalt 

Page 8 
.-

Interna l Paved Road 

E = VMT x k x (sUl2)0

·

63 x 

(W/3)1.s 

where: 

E = PM10 emissions~ tonslyr 

VMT ,.. annual vehicle miles 

traveled 

k == 0.016 lbs!VMT (AP-42) 

sL == road surface silt loading 

value in gjm1 

W == mean vehicle weight in 

tons 

Note: 

Aggr. ==Aggregate 

CP = Concrete Product 

Comparison of Assumptions for PM10 Baseline Emissions 

_...__ .. _. __ -':, .. ··. ' '-· - l' pr~- ,..-,,- . ·'5·· ·:~ ,.. ....::- ... .,Jfl'" ~lJf,f'•Jo .,..,!-ief 

VMT=(road length (ft) x #truck trips/day x # 

dayslyr) x lmile15280 ft 

sL= 1.45 gj m2 (Catalina Pacific Concrete source test 

data; Staff later determined that this value is for 

controlled environment) 

Assumed ooc~ed=30t and 

W lllllooded==5t (industry input) 

Assumed that 50% of the vehicles were loaded and 

50% were unloaded 

Assumed CE=SOo/o for chemical stabilizer 

VMT = (road length (ft) x # truck trlps/yr x 1 mile 

I 5280 ft 

• # truck trip/yr = annual throughput I truck 

capacity 

• Assumed tnlck capacity: 25 tons 

Same data and assumptions as in staff report 

except for sL values as follows: 

• . sL •ap-eam.cMa= 53 glm2 

• sL CB,CP,Oihcn= 1 1 gjm2 

• SL HMA= 76 g/m2 

(The above sL values are the lowest sL from 

AP-42) 

Pre-rule CE for water = 50% 

Assumed pre & post-rule CE for chemical 

stabilizer = 80% 

CB = Concrete Batching 

HMA == Hot Mix Asphalt 

CMB = Crushed Miscellaneous Base 

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