## ASARCO Hayden - revised visibility benefit from lower control efficiency, using scaling

A. Scale deciview benefit directly, in proportion to emission change B. Scale deciview-implied extinction in proportion to emissions, account for background in computing deciviews Natural background deciviews for best days from Guidance for Estimating Natural Visibility Conditions Under the Regional Haze Program, EPA-454/B-03-005. September 2003, Appendix B.
deciviews = dv = 10*ln(bext/10) (bext = extinction, proportional to emissions) CALPUFF delta deciviews = ddv = dv(source + background) - dv(background) = dv(bs + bg) - dv(bg) ddv = 10*ln( (bs + bg)/10 ) - 10*ln(bg/10) = 10*ln(bs/bg + 1) Invert this to get source extinction bs implied from ddv and natural background bg: bs = bg * ( expt(ddv/10) - 1 )

**SO2 emissions, lb/day Bag House**  **(base) Acid Plant** 

**(ctrl2)**

**Emission source** 15% 99.81% 14,294 14,294 146,947 328 9,692 9,692 Total 170,933 24,314 Reduction rel. to base 146,619 Overall control efficiency rel. to base 85.8% emissions ratio, ctrl2 rev. / ctrl2 reductions ratio, ctrl2 rev. / ctrl2

**Stack parameters from ASARCO July 2013 (CALPUFF "base", "ctrl2")**

EPA modeling results from NPR Delta deciviews Deciviews

Class I Area base: Base case, parms1 ctrl2: new

acid plant, parms1 original

benefit **A. revised**

**benefit, direct**  **scaling** benefit

shrinkage natural background Chiricahua NM 1.049 0.155 0.894 0.880 1.5% 1.80 Chiricahua Wild. 1.012 0.145 0.867 0.854 1.5% 1.79 Galiuro Wild. 1.729 0.279 1.450 1.428 1.5% 1.76 Gila Wild. 0.692 0.093 0.599 0.590 1.5% 1.83 Mazatzal Wild. 0.877 0.128 0.749 0.737 1.5% 1.79 Mount Baldy Wild. 0.655 0.094 0.561 0.552 1.5% 1.83 Petrified Forest NP 0.702 0.097 0.605 0.596 1.5% 1.85 Pine Mountain Wild. 0.667 0.098 0.569 0.560 1.5% 1.80 Saguaro NP 1.382 0.201 1.181 1.163 1.5% 1.72 Sierra Ancha Wild. 1.087 0.153 0.934 0.920 1.5% 1.80 Superstition Wild. 1.736 0.268 1.468 1.445 1.5% 1.76 Sycamore Canyon Wild. 0.513 0.073 0.440 0.433 1.5% 1.84 Cumulative (sum) 12.10 1.78 10.32 10.16 Maximum 1.74 0.28 1.47 1.45 # CIAs >= 0.5 dv 12 0 11 11

Primary Hood/Acid Plant, Main stack - inner Secondary Hood/Uncontrolled - annular stack Converter Bldg Fugitives**Stack parameters from 2012 stack test (CALPUFF "baset", "ctrl2t")** EPA modeling results from NPR Deciviews Deciviews

Class I Area baset: Base case, parms2 ctrl2t: new

acid plant, parms2 original

benefit **A. revised**

**benefit, direct**  **scaling** benefit

shrinkage natural background Chiricahua NM 1.122 0.172 0.950 0.935 1.5% 1.80 Chiricahua Wild. 1.084 0.167 0.917 0.903 1.5% 1.79 Galiuro Wild. 2.049 0.350 1.699 1.673 1.5% 1.76 Gila Wild. 0.702 0.104 0.598 0.589 1.5% 1.83 Mazatzal Wild. 1.054 0.157 0.897 0.883 1.5% 1.79 Mount Baldy Wild. 0.698 0.104 0.594 0.585 1.5% 1.83 Petrified Forest NP 0.673 0.107 0.566 0.557 1.5% 1.85 Pine Mountain Wild. 0.730 0.119 0.611 0.602 1.5% 1.80 Saguaro NP 1.637 0.240 1.397 1.375 1.5% 1.72 Sierra Ancha Wild. 1.268 0.192 1.076 1.059 1.5% 1.80 Superstition Wild. 2.109 0.369 1.740 1.713 1.5% 1.76 Sycamore Canyon Wild. 0.536 0.082 0.454 0.447 1.5% 1.84 Cumulative (sum) 13.66 2.16 11.50 11.32 Maximum 2.11 0.37 1.74 1.71 # CIAs >= 0.5 dv 12 0 11 11sjb 2014-06-05

Natural background deciviews for best days from Guidance for Estimating Natural Visibility Conditions Under the Regional Haze Program, EPA-454/B-03-005. September 2003, Appendix B.

Invert this to get source extinction bs implied from ddv and natural background bg: bs = bg * ( expt(ddv/10) - 1 )**Amine scrubber**  **(ctrl2 rev.)** 98.50%98.69% 14,294 Base case emissions are from original "ASARCO model emissions" spreadsheet 2593 9,692 26,579 144,354 84.5%98.46% **1.0931**for scaling extinction or impact **0.9846**for scaling benefit

Extinction Source ExtinctionScaled Delta deciviews

natural backgroundbase,

impliedctrl2, impliedctrl2 rev.ctrl2 (as

check) ctrl2 rev.**B. revised benefit,**  **using ddv**benefit

shrinkageDifference from direct scaling 11.9721.324 0.187 0.204 0.155 0.169 **0.880** -0.001 11.9601.274 0.175 0.191 0.145 0.158 **0.854** 0.000 11.9242.251 0.337 0.369 0.279 0.305 **1.424** -0.003 12.0080.860 0.112 0.123 0.093 0.102 **0.590** 0.001 11.9601.096 0.154 0.168 0.128 0.140 **0.737** 0.000 12.0080.813 0.113 0.124 0.094 0.103 **0.552** 0.000 12.0320.875 0.117 0.128 0.097 0.106 **0.596** 0.000 11.9720.826 0.118 0.129 0.098 0.107 **0.560** 0.000 11.8771.760 0.241 0.264 0.201 0.220 **1.162** 0.000 11.9721.375 0.185 0.202 0.153 0.167 **0.920** 0.000 11.9242.261 0.324 0.354 0.268 0.293 **1.443** -0.002 12.0200.633 0.088 0.096 0.073 0.080 **0.433** 0.000 1.78 1.95 **10.15** 0.28 0.30 **1.44** 0 0 **11**Extinction Source ExtinctionScaled Delta deciviews

natural backgroundbaset,

impliedctrl2t, impliedctrl2t rev.ctrl2t (as

check) ctrl2t rev.**B. revised benefit,**  **using ddv** Difference from direct scaling 11.9721.422 0.208 0.227 0.172 0.188 **0.934** -0.001 11.9601.369 0.201 0.220 0.167 0.182 **0.902** -0.001 11.9242.712 0.425 0.464 0.350 0.382 **1.667** -0.006 12.0080.873 0.126 0.137 0.104 0.114 **0.588** 0.000 11.9601.329 0.189 0.207 0.157 0.171 **0.883** -0.001 12.0080.868 0.126 0.137 0.104 0.114 **0.584** 0.000 12.0320.838 0.129 0.141 0.107 0.117 **0.556** -0.001 11.9720.907 0.143 0.157 0.119 0.130 **0.600** -0.002 11.8772.112 0.288 0.315 0.240 0.262 **1.375** 0.000 11.9721.619 0.232 0.254 0.192 0.210 **1.058** -0.001 11.9242.800 0.448 0.490 0.369 0.403 **1.706** -0.007 12.0200.662 0.099 0.108 0.082 0.090 **0.446** -0.001 2.16 2.36 **11.30** 0.37 0.40 **1.71** 0 0 **11**Base case emissions are from original "ASARCO model emissions" spreadsheet

Difference from direct scalingDifference from direct scaling