**Description**

**Column Heads** site VIEWS site code (except "MINGW" which is Warren White's substitution for Mingo data) param Parameter code (see below) ng10 Natural Conditions II mean of clearest 20% (mean of group 10) ng90 Natural Conditions II mean of haziest 20% (mean of group 90)

ncave Natural Conditions II annual mean sumg10n Number of observations in NCII group 10 sumg90n Number of observations in NCII group 90 sumN1 Total valid observations all groups all years sRay Site specific Rayleigh scattering value (Mm-1) N Number of valid years in average Meth Method code (See below) C10 RHR Baseline mean of clearest 20% (mean of group 10). Based on patched RHR data. C90 RHR Baseline mean of haziest 20% (mean of group 90). Based on patched RHR data. C RHR Baseline annual mean. Based on patched RHR data.

**Parameter code list Units**  aBext total aerosol extinction Mm-1
bCM coarse mass extinction Mm-1
bEC elemental carbon extinction Mm-1
bNO3 ammonium nitrate extinction Mm-1
bOMC organic extinction Mm-1
bSO4 ammonium sulfate extinction Mm-1
bSoil fine soil extinction Mm-1
bSs sea salt extinction Mm-1
CM coarse mass μg/m3 dv deciview = 10*ln((aBext+sRay)/10) EC elemental carbon mass μg/m3
NO3 ammonium nitrate mass μg/m3
OMC organic mass from carbon μg/m3
SO4 ammonium sulfate mass μg/m3
Soil fine soil mass μg/m3
Ss sea salt mass μg/m3

**Method code** NCII Natural Conditions II algorithm used NCII-VS Natural Conditions II algorithm used with Valid, Substituted data Thisfile contains the second version of the natural haze level II estimates based on the work of the Natural Haze Levels II values can be found here. These data fix a minor error in the first version of the natural haze level II estimates. The error below zero from the data set. This can only occur at sites above about 6000 feet (those with Rayleighvalues of 8 or 9 Mm can be as much as about 1.5 dv on clearest days and 0.5 dv on haziest days. The first version of these data did not includev of monitoring data. States have provided substituted data for missing data values at these sites that represent haze in class only the measured data and using measured data and substituted data values. Note, two versions of substituted data are availa Resource Specialists (ARS). Natural haze levels are estimated for each set of data and are labeled as MINGWand MING1 respectThisfile contains the second version of the natural haze level II estimates based on the work of the Natural Haze Levels II Committee. A description of the procedures for estimating these values can be found here. These data fix a minor error in the first version of the natural haze level II estimates. The error involvedthe unintentional removal of daily observationswith dv values below zero from the data set. This can only occur at sites above about 6000 feet (those with Rayleighvalues of 8 or 9 Mm

-1), and affects only about 30 sites. The magnitude of the difference can be as much as about 1.5 dv on clearest days and 0.5 dv on haziest days. The first version of these data did not includevalues for monitoring sites that with less than three complete years of monitoring data. States have provided substituted data for missing data values at these sites that represent haze in class I areas. For these sites the natural haze levels are estimated using only the measured data and using measured data and substituted data values. Note, two versions of substituted data are available for the MING site one provided by White and the other by Air Resource Specialists (ARS). Natural haze levels are estimated for each set of data and are labeled as MINGWand MING1 respectively.Natural Conditions II-V2

site param ng10 ng90 ncave sumg10n sumg90n sumN1 sRay BIBE1 aBext 1.773782 10.75348 5.281035 87 91 447 10 BIBE1 bCM 0.482242 4.232472 1.8 87 91 447 10 BIBE1 bEC 0.107574 0.272095 0.2 87 91 447 10 BIBE1 bNO3 0.181904 0.81908 0.434773 87 91 447 10 BIBE1 bOMC 0.68137 3.230059 1.774686 87 91 447 10 BIBE1 bSO4 0.192901 0.591589 0.466312 87 91 447 10 BIBE1 bSoil 0.111513 1.22886 0.5 87 91 447 10 BIBE1 bSs 0.016277 0.379321 0.105264 87 91 447 10 BIBE1 CM 0.803737 7.05412 3 87 91 447 10 BIBE1 dv 1.622494 7.158402 4.014705 87 91 447 10 BIBE1 EC 0.010757 0.02721 0.02 87 91 447 10 BIBE1 NO3 0.040085 0.191886 0.1 87 91 447 10 BIBE1 OMC 0.239193 1.052299 0.5994 87 91 447 10 BIBE1 SO4 0.045859 0.152115 0.115 87 91 447 10 BIBE1 Soil 0.111513 1.22886 0.5 87 91 447 10 BIBE1 Ss 0.004752 0.104293 0.029407 87 91 447 10 GUMO1 aBext 2.064272 10.83615 5.42819 101 104 512 9 GUMO1 bCM 0.490683 4.387111 1.8 101 104 512 9 GUMO1 bEC 0.135573 0.233484 0.2 101 104 512 9 GUMO1 bNO3 0.301102 0.885033 0.549769 101 104 512 9 GUMO1 bOMC 0.740526 3.125143 1.760917 101 104 512 9 GUMO1 bSO4 0.265988 0.797883 0.559221 101 104 512 9 GUMO1 bSoil 0.118857 1.266057 0.5 101 104 512 9 GUMO1 bSs 0.011542 0.141438 0.058283 101 104 512 9 GUMO1 CM 0.817804 7.311852 3 101 104 512 9 GUMO1 dv 0.991618 6.654037 3.412089 101 104 512 9 GUMO1 EC 0.013557 0.023348 0.02 101 104 512 9 GUMO1 NO3 0.05469 0.159378 0.1 101 104 512 9 GUMO1 OMC 0.259603 1.038301 0.5994 101 104 512 9 GUMO1 SO4 0.055254 0.166374 0.115 101 104 512 9 GUMO1 Soil 0.118857 1.266057 0.5 101 104 512 9 GUMO1 Ss 0.003393 0.039945 0.016279 101 104 512 9

Page 1Natural Conditions II-V2

N Meth C10 C90 C

4 NCII 8.061494 47.89149 24.69393 4 NCII 1.394438 7.025845 4.031517 4 NCII 0.65429 2.124283 1.276169 4 NCII 0.5045 2.045015 1.155788 4 NCII 1.476665 7.965371 3.955854 4 NCII 3.546452 26.09642 12.84674 4 NCII 0.381078 2.537411 1.322594 4 NCII 0.104071 0.09715 0.105264 4 NCII 2.324063 11.70974 6.719195 4 NCII 5.779771 17.30031 11.56982 4 NCII 0.065429 0.212428 0.127617 4 NCII 0.111951 0.466098 0.261564 4 NCII 0.508025 2.356319 1.257269 4 NCII 0.830696 5.192207 2.712744 4 NCII 0.381078 2.537411 1.322594 4 NCII 0.02981 0.028653 0.029407 5 NCII 9.416003 48.87262 25.13594 5 NCII 2.040315 16.02243 7.24921 5 NCII 0.720078 1.338448 1.067047 5 NCII 1.146777 3.808552 2.247837 5 NCII 1.603133 6.72684 3.751469 5 NCII 3.433381 16.5109 8.911498 5 NCII 0.414802 4.366678 1.851363 5 NCII 0.057517 0.098771 0.057513 5 NCII 3.400526 26.70405 12.08202 5 NCII 5.945114 17.18935 11.36944 5 NCII 0.072008 0.133845 0.106705 5 NCII 0.20725 0.654889 0.40303 5 NCII 0.54993 2.079472 1.215058 5 NCII 0.70217 2.984568 1.70435 5 NCII 0.414802 4.366678 1.851363 5 NCII 0.01682 0.027556 0.016259

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