Prof. Ravi Kant Pathak, Associate Professor at U. Gothenburg and founder of IGP-CARE, visited Columbia today to present a seminar on his work and discuss collaborations with the Clean Air Toolbox team. He presented recently published results on the chemical and physical transformations of soot particles as they age in the atmosphere (Pei et al., Atmos. Chem. Phys. (2018)). He also introduced IGP-CARE, the Indo Gangetic Plains Centre for Research and Education, and presented long-term measurements of short-lived climate forcers at a rural location in Uttar Pradesh, India. Long-term measurements at the IGP-CARE site reveal surprisingly high summertime ozone production.