IMPORTANT NOTICE Over the years the IMPROVE program has undergone a number of sampling and filter analysis changes to reduce biases and uncertainty and improve measurement sensitivities. These changes are documented in the quality control section of the IMPROVE website: http://vista.cira.colostate.edu/improve/Data/QA_QC/qa_qc_Branch.htm END SUB Two significant changes which can influence any trend work involved the fine sulfur mass and nitratate ion measurements. The sulfur measurement from the Module A Teflon filter can be underestimated by over a factor of 2. This bias occurred at only some Eastern US sites primarily during the summers of 1992-95 on days with the highest sulfur loadings coinciding with high humidity. This problem was rectified by increasing the size of the Teflon filters at affected sites (Table 1). It is recommended that data analysts use the sulfate ion measurement from the Module B filter instead of the Sulfur mass measurement from module A for time periods before the Teflon filter size was increased at the sites listed below (Table 1). For detailed information on the bias and recommendations see the QA/QC issues page on the IMPROVE website at: http://vista.cira.colostate.edu/improve/Data/QA_QC/issues.htm A temporal bias also exist in the Nitrate ion data. The nitrate data after 6/1996 tend to have smaller concentrations and variability. This is most pronounced in the Eastern US and along the West Coast. The change in the nitrate data coincides with the addition of glycerin to the denuders for the Module B sampler. However, a causality has not yet been established and is currently being studied. It is recommended that the nitrate data prior to 6/96 are not used for trends or mass and bext budgets. See the QA/QC issues page for detailed information. Post February 2000 IMPROVE data have only passed the Level 0 and Level 1 quality assurance and control procedure conducted by the Crocker Nuclear Laboratory at UC Davis. IMPROVE data prior to February 2000 data have undergone Level 3 quality control. Table 1. Monitoring sites and dates when the Teflon filter was increased from 2.2 sq. cm to 3.5 sq. cm : 19-Apr-95 DOSO1,GRSM1,SHEN1,JEFF1 22-Apr-95 SAGO1 26-Apr-95 ACAD1,LYBR1,SHRO1,MACA1 03-May-95 SIPS1,UPBU1 10-May-95 BRIG1 27-May-98 SEQU1 03-Jun-98 PUSO1 29-Jul-98 MOOS1 04-Aug-98 CHAS1,OKEF1,ROMA1,EVER1 17-Apr-01 CACR1 25-Apr-01 HEGL1,GUMO1,BIBE1 16-May-01 WIMO1 Note, there is no evidence of S underestimation at BIBE1, GUMO1, MOOS1, SAGO and SEQU. Note, as of 5/2/2002 all particle mass concentrations returned from the database query are reported in units of ug/m3. _________________________________________________________________________ Locations Network, Location, Site Name, Address, City, State, Longitude, Latitude, Elevation, Start Date, End Date IMPROVE, SACR1, Salt Creek, , , NM, -104.4042, 33.4597, 1077, 04/06/2000, Parameters Parameter, Parameter Name, Units NO3f, Nitrate: Fine, ug/m3 SO2, Sulfur Dioxide, ug/m3 SO4f, Sulfate: Fine, ug/m3 Attributes Attribute, Attribute Description Val, Value Monitoring Site(s) History Network_code, Location, Date, Description IMPROVE, SACR1, 04/06/2000, New IMPROVE site, version 2 sampler installed Network History Network, Date, Comments IMPROVE, 09/15/1990, The Global Geochemistry Company (GGC) took over the analysis of the Module B nylon filters for ions from Research Triangle Institute (RTI) IMPROVE, 06/01/1992, Analysis of IMPROVE filters for elements with atomic weights from Fe to Pb where changed from PIXE to XRF decreasing their minimum detection limits (MDL). The cyclotron time for the PIXE analysis was reduced increasing the MDLs for elements below FE. IMPROVE, 03/01/1994, Optical absorption measurement changed from Laser Integrating Plate Method (LIPM) to Hybrid Integrating Plate/Sphere Analysis (HIPS). IMPROVE, 06/19/1995, The Research Triangle Institute (RTI) laboratory took over the analysis of the Module B nylon filters for ions from Global Geochemistry Company (GGC) IMPROVE, 10/01/1996, Changed nylon filter manufactures from Gleman to MSI Data Network,Location,Obs_Date,Obs_Time,DOY,NO3f_Val,SO2_Val,SO4f_Val IMPROVE,SACR1,01/01/2001,00:00,1,6.5562,-999,8.2449 IMPROVE,SACR1,01/04/2001,00:00,4,1.3348,-999,0.4870 IMPROVE,SACR1,01/07/2001,00:00,7,0.9271,-999,0.4207 IMPROVE,SACR1,01/10/2001,00:00,10,1.6976,-999,1.1671 IMPROVE,SACR1,01/13/2001,00:00,13,0.4410,-999,0.6577 IMPROVE,SACR1,01/16/2001,00:00,16,1.9000,-999,1.7646 IMPROVE,SACR1,01/19/2001,00:00,19,0.9326,-999,0.7635 IMPROVE,SACR1,01/22/2001,00:00,22,2.4859,-999,0.9250 IMPROVE,SACR1,01/25/2001,00:00,25,4.7442,-999,3.3534 IMPROVE,SACR1,01/28/2001,00:00,28,1.4550,-999,1.5793 IMPROVE,SACR1,01/31/2001,00:00,31,1.4178,-999,1.5832 IMPROVE,SACR1,02/03/2001,00:00,34,0.5542,-999,0.6564 IMPROVE,SACR1,02/06/2001,00:00,37,0.6788,-999,0.7423 IMPROVE,SACR1,02/09/2001,00:00,40,0.8098,-999,0.8962 IMPROVE,SACR1,02/12/2001,00:00,43,1.1181,-999,1.9809 IMPROVE,SACR1,02/15/2001,00:00,46,0.2292,-999,0.4816 IMPROVE,SACR1,02/18/2001,00:00,49,1.6252,-999,1.8480 IMPROVE,SACR1,02/21/2001,00:00,52,0.6943,-999,0.8587 IMPROVE,SACR1,02/24/2001,00:00,55,0.2098,-999,0.6524 IMPROVE,SACR1,02/27/2001,00:00,58,0.6788,-999,1.2086 IMPROVE,SACR1,03/02/2001,00:00,61,1.0422,-999,0.9242 IMPROVE,SACR1,03/05/2001,00:00,64,2.4055,-999,1.4356 IMPROVE,SACR1,03/08/2001,00:00,67,0.1954,-999,0.3713 IMPROVE,SACR1,03/11/2001,00:00,70,0.2768,-999,0.7681 IMPROVE,SACR1,03/14/2001,00:00,73,0.3385,-999,0.7110 IMPROVE,SACR1,03/17/2001,00:00,76,0.4284,-999,0.9897 IMPROVE,SACR1,03/20/2001,00:00,79,1.0173,-999,1.6425 IMPROVE,SACR1,03/23/2001,00:00,82,0.9936,-999,2.0602 IMPROVE,SACR1,03/26/2001,00:00,85,1.3928,-999,1.5447 IMPROVE,SACR1,03/29/2001,00:00,88,1.0533,-999,1.3777 IMPROVE,SACR1,04/01/2001,00:00,91,2.0042,-999,2.8942 IMPROVE,SACR1,04/04/2001,00:00,94,0.1472,-999,0.7333 IMPROVE,SACR1,04/07/2001,00:00,97,0.1134,-999,0.4220 IMPROVE,SACR1,04/10/2001,00:00,100,0.2005,-999,3.0437 IMPROVE,SACR1,04/13/2001,00:00,103,0.2851,-999,1.0671 IMPROVE,SACR1,04/16/2001,00:00,106,0.8408,-999,1.9588 IMPROVE,SACR1,04/19/2001,00:00,109,0.5889,-999,1.8787 IMPROVE,SACR1,04/22/2001,00:00,112,0.1804,-999,2.1655 IMPROVE,SACR1,04/25/2001,00:00,115,0.6452,-999,0.9985 IMPROVE,SACR1,04/28/2001,00:00,118,1.0384,-999,4.2136 IMPROVE,SACR1,05/01/2001,00:00,121,-999,-999,-999 IMPROVE,SACR1,05/04/2001,00:00,124,-999,-999,-999 IMPROVE,SACR1,05/07/2001,00:00,127,-999,-999,-999 IMPROVE,SACR1,05/10/2001,00:00,130,0.4200,-999,1.4996 IMPROVE,SACR1,05/13/2001,00:00,133,-999,-999,-999 IMPROVE,SACR1,05/16/2001,00:00,136,0.1687,-999,0.8878 IMPROVE,SACR1,05/19/2001,00:00,139,0.1145,-999,0.8942 IMPROVE,SACR1,05/22/2001,00:00,142,0.2636,-999,0.7379 IMPROVE,SACR1,05/25/2001,00:00,145,0.1834,-999,1.0935 IMPROVE,SACR1,05/28/2001,00:00,148,0.2993,-999,2.3987 IMPROVE,SACR1,05/31/2001,00:00,151,0.1868,-999,1.4924 IMPROVE,SACR1,06/03/2001,00:00,154,0.1746,-999,1.9023 IMPROVE,SACR1,06/06/2001,00:00,157,0.3175,-999,1.3182 IMPROVE,SACR1,06/09/2001,00:00,160,0.1635,-999,0.9979 IMPROVE,SACR1,06/12/2001,00:00,163,0.2089,-999,1.4860 IMPROVE,SACR1,06/15/2001,00:00,166,0.1478,-999,0.6173 IMPROVE,SACR1,06/18/2001,00:00,169,0.4234,-999,1.1254 IMPROVE,SACR1,06/21/2001,00:00,172,0.2925,-999,1.8908 IMPROVE,SACR1,06/24/2001,00:00,175,0.3067,-999,1.6462 IMPROVE,SACR1,06/27/2001,00:00,178,0.3924,-999,1.7384 IMPROVE,SACR1,06/30/2001,00:00,181,0.2768,-999,1.6897 IMPROVE,SACR1,07/03/2001,00:00,184,0.1950,-999,0.6265 IMPROVE,SACR1,07/06/2001,00:00,187,0.3087,-999,1.5550 IMPROVE,SACR1,07/09/2001,00:00,190,0.5627,-999,1.7791 IMPROVE,SACR1,07/12/2001,00:00,193,0.3589,-999,1.6739 IMPROVE,SACR1,07/15/2001,00:00,196,0.3661,-999,1.7616 IMPROVE,SACR1,07/18/2001,00:00,199,0.2729,-999,1.5968 IMPROVE,SACR1,07/21/2001,00:00,202,0.1638,-999,2.0022 IMPROVE,SACR1,07/24/2001,00:00,205,0.2317,-999,1.4700 IMPROVE,SACR1,07/27/2001,00:00,208,0.3116,-999,3.0086 IMPROVE,SACR1,07/30/2001,00:00,211,0.3919,-999,1.8244 IMPROVE,SACR1,08/02/2001,00:00,214,0.3511,-999,1.9345 IMPROVE,SACR1,08/05/2001,00:00,217,0.4491,-999,3.7840 IMPROVE,SACR1,08/08/2001,00:00,220,0.2888,-999,2.3951 IMPROVE,SACR1,08/11/2001,00:00,223,0.2559,-999,2.1210 IMPROVE,SACR1,08/14/2001,00:00,226,0.3412,-999,1.3739 IMPROVE,SACR1,08/17/2001,00:00,229,0.8727,-999,2.8007 IMPROVE,SACR1,08/20/2001,00:00,232,0.6223,-999,2.1900 IMPROVE,SACR1,08/23/2001,00:00,235,0.2965,-999,2.4903 IMPROVE,SACR1,08/26/2001,00:00,238,0.1367,-999,1.0572 IMPROVE,SACR1,08/29/2001,00:00,241,0.2582,-999,1.4266 IMPROVE,SACR1,09/01/2001,00:00,244,0.2496,-999,1.1778 IMPROVE,SACR1,09/04/2001,00:00,247,0.1384,-999,1.2169 IMPROVE,SACR1,09/07/2001,00:00,250,0.1855,-999,0.7653 IMPROVE,SACR1,09/10/2001,00:00,253,0.5073,-999,2.1418 IMPROVE,SACR1,09/13/2001,00:00,256,0.3934,-999,4.8915 IMPROVE,SACR1,09/16/2001,00:00,259,0.1194,-999,1.2939 IMPROVE,SACR1,09/19/2001,00:00,262,0.2060,-999,2.0300 IMPROVE,SACR1,09/22/2001,00:00,265,0.2073,-999,1.4011 IMPROVE,SACR1,09/25/2001,00:00,268,0.7181,-999,1.4861 IMPROVE,SACR1,09/28/2001,00:00,271,0.2415,-999,1.1184 IMPROVE,SACR1,10/01/2001,00:00,274,0.9040,-999,2.6500 IMPROVE,SACR1,10/04/2001,00:00,277,0.2326,-999,1.7152 IMPROVE,SACR1,10/07/2001,00:00,280,0.5752,-999,1.6636 IMPROVE,SACR1,10/10/2001,00:00,283,0.1263,-999,0.8384 IMPROVE,SACR1,10/13/2001,00:00,286,0.2908,-999,0.3179 IMPROVE,SACR1,10/16/2001,00:00,289,0.4481,-999,0.5502 IMPROVE,SACR1,10/19/2001,00:00,292,0.4023,-999,0.6434 IMPROVE,SACR1,10/22/2001,00:00,295,0.1311,-999,0.8159 IMPROVE,SACR1,10/25/2001,00:00,298,0.1626,-999,0.4654 IMPROVE,SACR1,10/28/2001,00:00,301,1.0479,-999,4.0275 IMPROVE,SACR1,10/31/2001,00:00,304,0.0465,-999,0.6647 IMPROVE,SACR1,11/03/2001,00:00,307,4.2784,-999,11.6133 IMPROVE,SACR1,11/06/2001,00:00,310,0.1569,-999,1.2202 IMPROVE,SACR1,11/09/2001,00:00,313,1.1207,-999,0.8530 IMPROVE,SACR1,11/12/2001,00:00,316,1.0420,-999,3.3025 IMPROVE,SACR1,11/15/2001,00:00,319,0.1638,-999,0.3274 IMPROVE,SACR1,11/18/2001,00:00,322,1.0837,-999,1.5248 IMPROVE,SACR1,11/21/2001,00:00,325,2.7018,-999,1.4666 IMPROVE,SACR1,11/24/2001,00:00,328,0.0837,-999,0.1340 IMPROVE,SACR1,11/27/2001,00:00,331,0.3935,-999,0.6093 IMPROVE,SACR1,11/30/2001,00:00,334,0.6347,-999,0.7175 IMPROVE,SACR1,12/03/2001,00:00,337,2.0632,-999,1.4624 IMPROVE,SACR1,12/06/2001,00:00,340,0.7154,-999,0.3639 IMPROVE,SACR1,12/09/2001,00:00,343,0.5585,-999,0.2584 IMPROVE,SACR1,12/12/2001,00:00,346,0.2778,-999,0.8773 IMPROVE,SACR1,12/15/2001,00:00,349,0.4668,-999,0.3890 IMPROVE,SACR1,12/18/2001,00:00,352,0.1341,-999,0.2387 IMPROVE,SACR1,12/21/2001,00:00,355,0.6909,-999,0.6157 IMPROVE,SACR1,12/24/2001,00:00,358,0.9884,-999,0.5684 IMPROVE,SACR1,12/27/2001,00:00,361,0.6825,-999,0.3203 IMPROVE,SACR1,12/30/2001,00:00,364,0.8251,-999,0.8767