Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2017-306 Manuscript under review for journal Atmos. Chem. Phys. Discussion started: 17 July 2017 c Author(s) 2017. CC BY 3.0 License. Variations in surface ozone and carbon monoxide in the Kathmandu Valley and surrounding broader regions during SusKat‐ABC field campaign: Role of local and regional sources Piyush Bhardwaj1,2,*, Manish Naja1, Maheswar Rupakheti3, Arnico K. Panday4, Rajesh Kumar5, Khadak Mahata3, Shyam Lal6, Harish C. Chandola2, Mark G. Lawrence3 1Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital, 263002, India 2Dev Singh Bisht Campus, Kumaun University, Nainital, 263001, India *Now at Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea 3Institute for Advanced Sustainability Studies (IASS), Potsdam, 14467, Germany 4International Centre for Integrated Mountain Development (ICIMOD), Kathmandu, 44700, Nepal 5National Center for Atmospheric Research (NCAR) Boulder, 80301, USA 6Physical Research Laboratory (PRL), Ahmadabad, 380009, India Key words: Kathmandu, Himalayas, Air Pollution, Ozone, CO, Long Range Transport Correspondence to: Manish Naja (
[email protected]) 1 Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2017-306 Manuscript under review for journal Atmos. Chem. Phys. Discussion started: 17 July 2017 c Author(s) 2017. CC BY 3.0 License. Highlights of the study: A comparative study on trace gases among sites in the Kathmandu Valley and India. 5 An important contribution of regional transport to the springtime ozone enhancement in the Kathmandu Valley. 10 The winter time higher ozone levels in the Kathmandu Valley are largely due to local sources. 15 O3, CO and light NMHCs levels are higher in the Kathmandu Valley than the site in IGP.