Black Smoke and Black Carbon: Further investigation of the relationship between these ambient air metrics

A previous paper (Quincey, 2007) described a simple quadratic relationship between OECD Black Smoke Index (IBS) and Black Carbon (aethalometry) measurements of ambient particulate samples (CBC): CBC=4.18IBS+59.6−7.72, based on their common link to optical absorption coefficient, supported by a single dataset. Further parallel datasets are presented here that support the general validity of the relationship, while highlighting limitations to the traditional Black Smoke method at kerbside sites, and variations between sites. The opportunity is taken to clarify some confusing aspects concerning published standard methods for Black Smoke.

► Modified relationship between Black Smoke and Black Carbon parameters derived.
► New parallel measurements of Black Smoke and Black Carbon at five sites presented.
► Derived relationship holds experimentally within ∼25% except at kerbside site.
► Kerbside anomaly attributed to failure of Black Smoke method with high diesel soot.