Vertical profiles of black carbon aerosols over the urban locations in South India.

Vertical profiles of black carbon (BC) aerosol were determined from aircraft measurements under the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) program conducted by the Indian Institute of Tropical Meteorology, India during 2009 over Bangalore and Hyderabad in south India. BC mass loadings decreased approximately monotonically from 10(3) to 10(4) ng/m(3) at the surface to ~10(2) ng/m(3) at an altitude of about 7 km; although layers at intermediate levels containing anomalously high BC loadings were frequently encountered that were attributed mainly to the convective transport from surface sources accompanied by changes in the local boundary layer and atmospheric stability. In addition, as evidenced from air mass back trajectories; long range transport from distant sources contributed to some anomalous spikes in BC concentration. The presence of BC in cloud forming regions of the free troposphere could have important implications for cloud microphysics and subsequent rainfall mechanism over this region. Apart from this, the effects on human health are equally important.