title: Harmonizing aerosol carbon measurements between two conventional thermal/optical analysis methods.
abstract: Although total carbon (TC) can be consistently quantified by various aerosol carbon measurement methods, the demarcation of TC into organic carbon (OC) and elemental carbon (EC) has long been inconsistent. The NIOSH and IMPROVE protocols are most widely used for thermal/optical analysis (TOA), but current knowledge rests in the description that the NIOSH protocol usually gives lower EC values than does the IMPROVE protocol. This study seeks to explore the possibility of quantitatively linking the difference between the two TOA protocols. Residential coal-burning samples that had been collected and analyzed following the NIOSH protocol in previous studies were directly reanalyzed following the IMPROVE protocol for this study. A comparison of each pair of NIOSH and IMPROVE EC values reveals the dynamic relation between the two protocols, which can be expressed as a regression equation, y=(1-x)/(1+4.86x2) (R2=0.96), where the independent x is the EC/TC ratio R(EC/TC) for the IMPROVE protocol, and the dependent y is the difference between IMPROVE and NIOSH REC/TC relative to IMPROVE REC/TC. This regression equation may be the first effort in formulating the relationship between the two TOA protocols, and it is very helpful in harmonizing inconsistent TOA measurements, for example, source characterization, ambient monitoring, and atmospheric modeling.
authors.affiliation: Chinese Academy of Meteorological Sciences, Beijing 100081, China. zhigr68@yahoo.com.cn
authors.forename: Guorui
authors.initials: G
authors.lastname: Zhi
authors.forename: Yingjun
authors.initials: Y
authors.lastname: Chen
authors.forename: Junying
authors.initials: J
authors.lastname: Sun
authors.forename: Laiguo
authors.initials: L
authors.lastname: Chen
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Tian
authors.forename: Jingchun
authors.initials: J
authors.lastname: Duan
authors.forename: Gan
authors.initials: G
authors.lastname: Zhang
authors.forename: Fahe
authors.initials: F
authors.lastname: Chai
authors.forename: Guoying
authors.initials: G
authors.lastname: Sheng
authors.forename: Jiamo
authors.initials: J
authors.lastname: Fu
mesh_terms: D000336:Aerosols / Q000032:analysis*; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000706:statistics & numerical data; D002244:Carbon / Q000032:analysis*; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D008956:Models, Chemical; D009314:National Institute for Occupational Safety and Health, U.S.; D058998:Remote Sensing Technology; D014481:United States
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D002244:Carbon