ABC international field campaign using positive matrix factorization

General comment: The manuscript shows results of a source apportionment study of NMVOCs measured by PTR-TOF-MS in the Kathmandu Valley in Nepal during winter 2013. Positive matrix factorization analysis was conducted to identify possible emission sources for 37 m/z measured by PTR-MS. The sources were identified from the chemical fingerprint of each PMF factor and their diurnal profiles. Conditional probability functions plots were used to determine the directions of the sources and attribute the chemical emissions to specific spatial areas in the region and specific activities. The sources found by the authors through PMF were compared with the results of current emission inventories used for Nepal, which, in contrast to the authors results, rely on sources emission factors measured in other regions of the world and are not supported by in-situ collected measurements. Sources and species contributions differ among the authors results and the current inventories as well as between different inventories. Finally, the atmospheric impact as daytime ozone production and SOA formation based on the measured compounds and PMF sources contributions is briefly discussed. I found the manuscript very interesting, of high quality and of high impact as it presents several new findings which can help mitigating the emissions in the region under study. The presented topic also follows in the scope of ACP. The article is overall well written, and results are presented clearly with figures and tables. I highly recommend the manuscript publication, once these specific comments have been addressed: