Black carbon aerosols over tropical urban environment—a case study

Black carbon (BC) has become the subject of interest in the recent years for a variety of reasons. BC aerosol may cause environmental as well as harmful health effects in densely inhabited regions. Since BC is a strong absorber of radiation in the visible and near-infrared part of the spectrum, where most of the solar energy is distributed. Black carbon is emitted into the atmosphere as a byproduct of all combustion processes viz., vegetation burning, industrial effluents and motor vehicle exhausts, etc. In the present study, measurements of Black Carbon Aerosols and traffic density have been carried out during January to July to study the impact of mobile sources on black carbon concentrations over a typical urban environment namely Hyderabad, India. Diurnal variations BC suggest that BC concentrations are high by a factor of ∼2 during morning (0600 to 0900 h) and evening hours (1900 to 2300 h) compared to afternoon hours. Compared to weekdays, significant reduction in BC values has been observed during weekends. BC concentrations are high during dry season compared to rainy season and are correlated with the traffic density. The results are discussed in detail in the paper.