TY - JOUR
T1 - Optical and thermal measurements of black carbon aerosol content in different environments
T2 - Variation of the specific attenuation cross-section, sigma (σ)
AU - Liousse, C.
AU - Cachier, H.
AU - Jennings, S. G.
PY - 1993/6
Y1 - 1993/6
N2 - In optical analysers devoted to the analysis of atmospheric black carbon concentration, the specific attenuation cross-section, σ is the factor used to convert the attenuation of a light beam due to the absorption of aerosols deposited on a filter into their black carbon content. We have tried to gain further insight for a suitable choice of sigma value, using both optical analysis (with an aethalometer) and thermal analysis of black carbon aerosols and comparison of the two sets of results. Samples which were investigated originate from varying environments, including suburban areas, tropical areas where biomass burning was prevalent and from more remote locations. In a given type of atmospheric environment, σ values are found to be constant. However, σ displays an important variability (range: 5-20 m2 g-1) which may be related to the variability of the aerosol mix (internal or external mixture) and the aging of the atmospheric particulate phase. Our results quote unambiguously the need for a modulated calibration of optical analysers depending on the type of atmospheric environments which are studied. They suggest the need to reconsider carefully the black carbon data obtained at remote locations.
AB - In optical analysers devoted to the analysis of atmospheric black carbon concentration, the specific attenuation cross-section, σ is the factor used to convert the attenuation of a light beam due to the absorption of aerosols deposited on a filter into their black carbon content. We have tried to gain further insight for a suitable choice of sigma value, using both optical analysis (with an aethalometer) and thermal analysis of black carbon aerosols and comparison of the two sets of results. Samples which were investigated originate from varying environments, including suburban areas, tropical areas where biomass burning was prevalent and from more remote locations. In a given type of atmospheric environment, σ values are found to be constant. However, σ displays an important variability (range: 5-20 m2 g-1) which may be related to the variability of the aerosol mix (internal or external mixture) and the aging of the atmospheric particulate phase. Our results quote unambiguously the need for a modulated calibration of optical analysers depending on the type of atmospheric environments which are studied. They suggest the need to reconsider carefully the black carbon data obtained at remote locations.
KW - aerosol light absorption
KW - Black carbon
KW - black carbon optical analysis
KW - remote regions
KW - specific attenuation cross-section
UR - http://www.scopus.com/inward/record.url?scp=0027607446&partnerID=8YFLogxK
U2 - 10.1016/0960-1686(93)90246-U
DO - 10.1016/0960-1686(93)90246-U
M3 - Article
AN - SCOPUS:0027607446
SN - 0960-1686
VL - 27
SP - 1203
EP - 1211
JO - Atmospheric Environment Part A, General Topics
JF - Atmospheric Environment Part A, General Topics
IS - 8
ER -