TY  - JOUR
A1  - Middeldorp, Christel M.
A1  - Mahajan, Anubha
A1  - Horikoshi, Momoko
A1  - Robertson, Neil R.
A1  - Beaumont, Robin N.
A1  - Bradfield, Jonathan P.
A1  - Bustamante, Mariona
A1  - Cousminer, Diana L.
A1  - Day, Felix R.
A1  - De Silva, N. Maneka
A1  - Guxens, Monica
A1  - Mook-Kanamori, Dennis O.
A1  - St Pourcain, Beate
A1  - Warrington, Nicole M.
A1  - Adair, Linda S.
A1  - Ahlqvist, Emma
A1  - Ahluwalia, Tarunveer Singh
A1  - Almgren, Peter
A1  - Ang, Wei
A1  - Atalay, Mustafa
A1  - Auvinen, Juha
A1  - Bartels, Meike
A1  - Beckmann, Jacques S.
A1  - Bilbao, Jose Ramon
A1  - Bond, Tom
A1  - Borja, Judith B.
A1  - Cavadino, Alana
A1  - Charoen, Pimphen
A1  - Chen, Zhanghua
A1  - Coin, Lachlan
A1  - Cooper, Cyrus
A1  - Curtin, John A.
A1  - Custovic, Adnan
A1  - Das, Shikta
A1  - Davies, Gareth E.
A1  - Dedoussis, George V.
A1  - Duijts, Liesbeth
A1  - Eastwood, Peter R.
A1  - Eliasen, Anders U.
A1  - Elliott, Paul
A1  - Eriksson, Johan G.
A1  - Estivill, Xavier
A1  - Fadista, Joao
A1  - Fedko, Iryna O.
A1  - Frayling, Timothy M.
A1  - Gaillard, Romy
A1  - Gauderman, W. James
A1  - Geller, Frank
A1  - Gilliland, Frank
A1  - Gilsanz, Vincente
A1  - Granell, Raquel
A1  - Grarup, Niels
A1  - Groop, Leif
A1  - Hadley, Dexter
A1  - Hakonarson, Hakon
A1  - Hansen, Torben
A1  - Hartman, Catharina A.
A1  - Hattersley, Andrew T.
A1  - Hayes, M. Geoffrey
A1  - Hebebrand, Johannes
A1  - Heinrich, Joachim
A1  - Helgeland, Oyvind
A1  - Henders, Anjali K.
A1  - Henderson, John
A1  - Henriksen, Tine B.
A1  - Hirschhorn, Joel N.
A1  - Hivert, Marie-France
A1  - Hocher, Berthold
A1  - Holloway, John W.
A1  - Holt, Patrick
A1  - Hottenga, Jouke-Jan
A1  - Hypponen, Elina
A1  - Iniguez, Carmen
A1  - Johansson, Stefan
A1  - Jugessur, Astanand
A1  - Kahonen, Mika
A1  - Kalkwarf, Heidi J.
A1  - Kaprio, Jaakko
A1  - Karhunen, Ville
A1  - Kemp, John P.
A1  - Kerkhof, Marjan
A1  - Koppelman, Gerard H.
A1  - Korner, Antje
A1  - Kotecha, Sailesh
A1  - Kreiner-Moller, Eskil
A1  - Kulohoma, Benard
A1  - Kumar, Ashish
A1  - Kutalik, Zoltan
A1  - Lahti, Jari
A1  - Lappe, Joan M.
A1  - Larsson, Henrik
A1  - Lehtimaki, Terho
A1  - Lewin, Alexandra M.
A1  - Li, Jin
A1  - Lichtenstein, Paul
A1  - Lindgren, Cecilia M.
A1  - Lindi, Virpi
A1  - Linneberg, Allan
A1  - Liu, Xueping
A1  - Liu, Jun
A1  - Lowe, William L.
A1  - Lundstrom, Sebastian
A1  - Lyytikainen, Leo-Pekka
A1  - Ma, Ronald C. W.
A1  - Mace, Aurelien
A1  - Magi, Reedik
A1  - Magnus, Per
A1  - Mamun, Abdullah A.
A1  - Mannikko, Minna
A1  - Martin, Nicholas G.
A1  - Mbarek, Hamdi
A1  - McCarthy, Nina S.
A1  - Medland, Sarah E.
A1  - Melbye, Mads
A1  - Melen, Erik
A1  - Mohlke, Karen L.
A1  - Monnereau, Claire
A1  - Morgen, Camilla S.
A1  - Morris, Andrew P.
A1  - Murray, Jeffrey C.
A1  - Myhre, Ronny
A1  - Najman, Jackob M.
A1  - Nivard, Michel G.
A1  - Nohr, Ellen A.
A1  - Nolte, Ilja M.
A1  - Ntalla, Ioanna
A1  - Oberfield, Sharon E.
A1  - Oken, Emily
A1  - Oldehinkel, Albertine J.
A1  - Pahkala, Katja
A1  - Palviainen, Teemu
A1  - Panoutsopoulou, Kalliope
A1  - Pedersen, Oluf
A1  - Pennell, Craig E.
A1  - Pershagen, Goran
A1  - Pitkanen, Niina
A1  - Plomin, Robert
A1  - Power, Christine
A1  - Prasad, Rashmi B.
A1  - Prokopenko, Inga
A1  - Pulkkinen, Lea
A1  - Raikkonen, Katri
A1  - Raitakari, Olli T.
A1  - Reynolds, Rebecca M.
A1  - Richmond, Rebecca C.
A1  - Rivadeneira, Fernando
A1  - Rodriguez, Alina
A1  - Rose, Richard J.
A1  - Salem, Rany
A1  - Santa-Marina, Loreto
A1  - Saw, Seang-Mei
A1  - Schnurr, Theresia M.
A1  - Scott, James G.
A1  - Selzam, Saskia
A1  - Shepherd, John A.
A1  - Simpson, Angela
A1  - Skotte, Line
A1  - Sleiman, Patrick M. A.
A1  - Snieder, Harold
A1  - Sorensen, Thorkild I. A.
A1  - Standl, Marie
A1  - Steegers, Eric A. P.
A1  - Strachan, David P.
A1  - Straker, Leon
A1  - Strandberg, Timo
A1  - Taylor, Michelle
A1  - Teo, Yik-Ying
A1  - Thiering, Elisabeth
A1  - Torrent, Maties
A1  - Tyrrell, Jessica
A1  - Uitterlinden, Andre G.
A1  - van Beijsterveldt, Toos
A1  - van der Most, Peter J.
A1  - van Duijn, Cornelia M.
A1  - Viikari, Jorma
A1  - Vilor-Tejedor, Natalia
A1  - Vogelezang, Suzanne
A1  - Vonk, Judith M.
A1  - Vrijkotte, Tanja G. M.
A1  - Vuoksimaa, Eero
A1  - Wang, Carol A.
A1  - Watkins, William J.
A1  - Wichmann, H-Erich
A1  - Willemsen, Gonneke
A1  - Williams, Gail M.
A1  - Wilson, James F.
A1  - Wray, Naomi R.
A1  - Xu, Shujing
A1  - Xu, Cheng-Jian
A1  - Yaghootkar, Hanieh
A1  - Yi, Lu
A1  - Zafarmand, Mohammad Hadi
A1  - Zeggini, Eleftheria
A1  - Zemel, Babette S.
A1  - Hinney, Anke
A1  - Lakka, Timo A.
A1  - Whitehouse, Andrew J. O.
A1  - Sunyer, Jordi
A1  - Widen, Elisabeth E.
A1  - Feenstra, Bjarke
A1  - Sebert, Sylvain
A1  - Jacobsson, Bo
A1  - Njolstad, Pal R.
A1  - Stoltenberg, Camilla
A1  - Smith, George Davey
A1  - Lawlor, Debbie A.
A1  - Paternoster, Lavinia
A1  - Timpson, Nicholas J.
A1  - Ong, Ken K.
A1  - Bisgaard, Hans
A1  - Bonnelykke, Klaus
A1  - Jaddoe, Vincent W. V.
A1  - Tiemeier, Henning
A1  - Jarvelin, Marjo-Riitta
A1  - Evans, David M.
A1  - Perry, John R. B.
A1  - Grant, Struan F. A.
A1  - Boomsma, Dorret I.
A1  - Freathy, Rachel M.
A1  - McCarthy, Mark I.
A1  - Felix, Janine F.
T1  - The Early Growth Genetics (EGG) and EArly Genetics and Lifecourse Epidemiology (EAGLE) consortia
BT  - design, results and future prospects
JF  - European journal of epidemiology
N2  - The impact of many unfavorable childhood traits or diseases, such as low birth weight and mental disorders, is not limited to childhood and adolescence, as they are also associated with poor outcomes in adulthood, such as cardiovascular disease. Insight into the genetic etiology of childhood and adolescent traits and disorders may therefore provide new perspectives, not only on how to improve wellbeing during childhood, but also how to prevent later adverse outcomes. To achieve the sample sizes required for genetic research, the Early Growth Genetics (EGG) and EArly Genetics and Lifecourse Epidemiology (EAGLE) consortia were established. The majority of the participating cohorts are longitudinal population-based samples, but other cohorts with data on early childhood phenotypes are also involved. Cohorts often have a broad focus and collect(ed) data on various somatic and psychiatric traits as well as environmental factors. Genetic variants have been successfully identified for multiple traits, for example, birth weight, atopic dermatitis, childhood BMI, allergic sensitization, and pubertal growth. Furthermore, the results have shown that genetic factors also partly underlie the association with adult traits. As sample sizes are still increasing, it is expected that future analyses will identify additional variants. This, in combination with the development of innovative statistical methods, will provide detailed insight on the mechanisms underlying the transition from childhood to adult disorders. Both consortia welcome new collaborations. Policies and contact details are available from the corresponding authors of this manuscript and/or the consortium websites.
KW  - Genetics
KW  - Consortium
KW  - Childhood traits and disorders
KW  - Longitudinal
Y1  - 2019
U6  - https://doi.org/10.1007/s10654-019-00502-9
SN  - 0393-2990
SN  - 1573-7284
VL  - 34
IS  - 3
SP  - 279
EP  - 300
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - GEN
A1  - Mahata, Khadak Singh
A1  - Panday, Arnico Kumar
A1  - Rupakheti, Maheswar
A1  - Singh, Ashish
A1  - Naja, Manish
A1  - Lawrence, Mark
T1  - Seasonal and diurnal variations in methane and carbon dioxide in the Kathmandu Valley in the foothills of the central Himalayas
T2  - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe
N2  - The SusKat-ABC (Sustainable Atmosphere for the Kathmandu Valley-Atmospheric Brown Clouds) international air pollution measurement campaign was carried out from December 2012 to June 2013 in the Kathmandu Valley and surrounding regions in Nepal. The Kathmandu Valley is a bowl-shaped basin with a severe air pollution problem. This paper reports measurements of two major greenhouse gases (GHGs), methane (CH4) and carbon dioxide (CO2), along with the pollutant CO, that began during the campaign and were extended for 1 year at the SusKat-ABC supersite in Bode, a semi-urban location in the Kathmandu Valley. Simultaneous measurements were also made during 2015 in Bode and a nearby rural site (Chanban) similar to 25 km (aerial distance) to the southwest of Bode on the other side of a tall ridge. The ambient mixing ratios of methane (CH4), carbon dioxide (CO2), water vapor, and carbon monoxide (CO) were measured with a cavity ring-down spectrometer (G2401; Picarro, USA) along with meteorological parameters for 1 year (March 2013-March 2014). These measurements are the first of their kind in the central Himalayan foothills. At Bode, the annual average mixing ratios of CO2 and CH4 were 419.3 (+/- 6.0) ppm and 2.192 (+/- 0.066) ppm, respectively. These values are higher than the levels observed at background sites such as Mauna Loa, USA (CO2: 396.8 +/- 2.0 ppm, CH4: 1.831 +/- 0.110 ppm) and Waliguan, China (CO2: 397.7 +/- 3.6 ppm, CH4: 1.879 +/- 0.009 ppm) during the same period and at other urban and semi-urban sites in the region, such as Ahmedabad and Shadnagar (India). They varied slightly across the seasons at Bode, with seasonal average CH4 mixing ratios of 2.157 (+/- 0.230) ppm in the pre-monsoon season, 2.199 (+/- 0.241) ppm in the monsoon, 2.210 (+/- 0.200) ppm in the post-monsoon, and 2.214 (+/- 0.209) ppm in the winter season. The average CO2 mixing ratios were 426.2 (+/- 25.5) ppm in the pre-monsoon, 413.5 (+/- 24.2) ppm in the monsoon, 417.3 (+/- 23.1) ppm in the postmonsoon, and 421.9 (+/- 20.3) ppm in the winter season. The maximum seasonal mean mixing ratio of CH4 in winter was only 0.057 ppm or 2.6% higher than the seasonal minimum during the pre-monsoon period, while CO2 was 12.8 ppm or 3.1% higher during the pre-monsoon period (seasonal maximum) than during the monsoon (seasonal minimum). On the other hand, the CO mixing ratio at Bode was 191% higher during the winter than during the monsoon season. The enhancement in CO2 mixing ratios during the pre-monsoon season is associated with additional CO2 emissions from forest fires and agro-residue burning in northern South Asia in addition to local emissions in the Kathmandu Valley. Published CO = CO2 ratios of different emission sources in Nepal and India were compared with the observed CO = CO2 ratios in this study. This comparison suggested that the major sources in the Kathmandu Valley were residential cooking and vehicle exhaust in all seasons except winter. In winter, brick kiln emissions were a major source. Simultaneous measurements in Bode and Chanban (15 July-3 October 2015) revealed that the mixing ratios of CO2, CH4, and CO were 3.8, 12, and 64% higher in Bode than Chanban.

The Kathmandu Valley thus has significant emissions from local sources, which can also be attributed to its bowl-shaped geography that is conducive to pollution build-up. At Bode, all three gas species (CO2, CH4, and CO) showed strong diurnal patterns in their mixing ratios with a pronounced morning peak (ca. 08:00), a dip in the afternoon, and a gradual increase again through the night until the next morning. CH4 and CO at Chanban, however, did not show any noticeable diurnal variations.

These measurements provide the first insights into the diurnal and seasonal variation in key greenhouse gases and air pollutants and their local and regional sources, which is important information for atmospheric research in the region.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 610 
KW  - air-pollution transport
KW  - black carbon
KW  - trace gases
KW  - numerical-simulation
KW  - ozone concentrations
KW  - late wintertime
KW  - South-Asia
KW  - urban site
KW  - NCOP
KW  - India
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-416643
IS  - 610
SP  - 12573
EP  - 12596
ER  - 
TY  - GEN
A1  - Mahata, Khadak Singh
A1  - Rupakheti, Maheswar
A1  - Panday, Arnico Kumar
A1  - Bhardwaj, Piyush
A1  - Naja, Manish
A1  - Singh, Ashish
A1  - Mues, Andrea
A1  - Cristofanelli, Paolo
A1  - Pudasainee, Deepak
A1  - Bonasoni, Paolo
A1  - Lawrence, Mark
T1  - Observation and analysis of spatio-temporal characteristics of surface ozone and carbon monoxide at multiple sites in the Kathmandu Valley, Nepal
T2  - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe
N2  - Residents of the Kathmandu Valley experience severe particulate and gaseous air pollution throughout most of the year, even during much of the rainy season. The knowledge base for understanding the air pollution in the Kathmandu Valley was previously very limited, but is improving rapidly due to several field measurement studies conducted in the last few years. Thus far, most analyses of observations in the Kathmandu Valley have been limited to short periods of time at single locations. This study extends on the past studies by examining the spatial and temporal characteristics of two important gaseous air pollutant (CO and O3) based on simultaneous observations over a longer period at five locations within the valley and on its rim, including a supersite (at Bode in the valley center, 1345m above sea level) and four satellite sites (at Paknajol, 1380masl in the Kathmandu city center, at Bhimdhunga (1522masl), a mountain pass on the valley's western rim, at Nagarkot (1901masl), another mountain pass on the eastern rim, and Naikhandi, near the valley's only river outlet). CO and O3 mixing ratios were monitored from January to July 2013, along with other gases and aerosol particles by instruments deployed at the Bode supersite during the international air pollution measurement campaign SusKat-ABC (Sustainable Atmosphere for the Kathmandu Valley – endorsed by the Atmospheric Brown Clouds program of UNEP). The O3 monitoring at Bode, Paknajol and Nagarkot as well as the CO monitoring at Bode were extended beyond July 2013 to investigate their variability over a complete annual cycle. Higher CO mixing ratios were found at Bode than at the outskirt sites (Bhimdhunga, Naikhandi and Nagarkot), and all sites except Nagarkot showed distinct diurnal cycles of CO mixing ratio with morning peaks and daytime lows. Seasonally, CO was higher during the pre-monsoon and winter seasons, especially due to the emissions from brick kiln industries, which only operate during this period, as well as increased domestic heating during winter, and regional forest fires and agro-residue burning. It was lower during the monsoon due to rainfall, which reduces open burning activities within the valley and in the surrounding regions, and thus reduces the sources of CO. The meteorology of the valley also played a key role in determining the CO mixing ratios. Furthermore, there was evidence of some influence of pollution from the greater region around the valley. A top-down estimate of the CO emission flux was made by using the CO mixing ratio and mixing layer height (MLH) measured at Bode. The estimated annual CO flux at Bode was 4.92μgm−2s−1, which is 2–14 times higher than that in widely used emission inventory databases (EDGAR HTAP, REAS and INTEX-B). This difference in CO flux between Bode and other emission databases likely arises from large uncertainties in both the top-down and bottom-up approaches to estimating the emission flux. The O3 mixing ratio was found to be highest during the pre-monsoon season at all sites, while the timing of the seasonal minimum varied across the sites. The daily maximum 8 hour average O3 exceeded the WHO recommended guideline of 50ppb on more days at the hilltop station of Nagarkot (159/357 days) than at the urban valley bottom sites of Paknajol (132/354 days) and Bode (102/353 days), presumably due to the influence of free-tropospheric air at the high-altitude site, as well as to titration of O3 by fresh NOx emissions near the urban sites. More than 78% of the exceedance days were during the pre-monsoon period at all sites. This was due to both favorable meteorological conditions as well as contributions of precursors from regional sources such as forest fires and agro-residue burning. The high O3 mixing ratio observed during the pre-monsoon period is of a high concern for human health and ecosystems, including agroecosystems in the Kathmandu Valley and surrounding regions.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 848 
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-416626
SN  - 1866-8372
IS  - 848
ER  - 
TY  - JOUR
A1  - Mahata, Khadak Singh
A1  - Panday, Arnico Kumar
A1  - Rupakheti, Maheswar
A1  - Singh, Ashish
A1  - Naja, Manish
A1  - Lawrence, Mark
T1  - Seasonal and diurnal variations in methane and carbon dioxide in the Kathmandu Valley in the foothills of the central Himalayas
JF  - Atmospheric Chemistry and Physics
N2  - The SusKat-ABC (Sustainable Atmosphere for the Kathmandu Valley-Atmospheric Brown Clouds) international air pollution measurement campaign was carried out from December 2012 to June 2013 in the Kathmandu Valley and surrounding regions in Nepal. The Kathmandu Valley is a bowl-shaped basin with a severe air pollution problem. This paper reports measurements of two major greenhouse gases (GHGs), methane (CH4) and carbon dioxide (CO2), along with the pollutant CO, that began during the campaign and were extended for 1 year at the SusKat-ABC supersite in Bode, a semi-urban location in the Kathmandu Valley. Simultaneous measurements were also made during 2015 in Bode and a nearby rural site (Chanban) similar to 25 km (aerial distance) to the southwest of Bode on the other side of a tall ridge. The ambient mixing ratios of methane (CH4), carbon dioxide (CO2), water vapor, and carbon monoxide (CO) were measured with a cavity ring-down spectrometer (G2401; Picarro, USA) along with meteorological parameters for 1 year (March 2013-March 2014). These measurements are the first of their kind in the central Himalayan foothills. At Bode, the annual average mixing ratios of CO2 and CH4 were 419.3 (+/- 6.0) ppm and 2.192 (+/- 0.066) ppm, respectively. These values are higher than the levels observed at background sites such as Mauna Loa, USA (CO2: 396.8 +/- 2.0 ppm, CH4: 1.831 +/- 0.110 ppm) and Waliguan, China (CO2: 397.7 +/- 3.6 ppm, CH4: 1.879 +/- 0.009 ppm) during the same period and at other urban and semi-urban sites in the region, such as Ahmedabad and Shadnagar (India). They varied slightly across the seasons at Bode, with seasonal average CH4 mixing ratios of 2.157 (+/- 0.230) ppm in the pre-monsoon season, 2.199 (+/- 0.241) ppm in the monsoon, 2.210 (+/- 0.200) ppm in the post-monsoon, and 2.214 (+/- 0.209) ppm in the winter season. The average CO2 mixing ratios were 426.2 (+/- 25.5) ppm in the pre-monsoon, 413.5 (+/- 24.2) ppm in the monsoon, 417.3 (+/- 23.1) ppm in the postmonsoon, and 421.9 (+/- 20.3) ppm in the winter season. The maximum seasonal mean mixing ratio of CH4 in winter was only 0.057 ppm or 2.6% higher than the seasonal minimum during the pre-monsoon period, while CO2 was 12.8 ppm or 3.1% higher during the pre-monsoon period (seasonal maximum) than during the monsoon (seasonal minimum). On the other hand, the CO mixing ratio at Bode was 191% higher during the winter than during the monsoon season. The enhancement in CO2 mixing ratios during the pre-monsoon season is associated with additional CO2 emissions from forest fires and agro-residue burning in northern South Asia in addition to local emissions in the Kathmandu Valley. Published CO = CO2 ratios of different emission sources in Nepal and India were compared with the observed CO = CO2 ratios in this study. This comparison suggested that the major sources in the Kathmandu Valley were residential cooking and vehicle exhaust in all seasons except winter. In winter, brick kiln emissions were a major source. Simultaneous measurements in Bode and Chanban (15 July-3 October 2015) revealed that the mixing ratios of CO2, CH4, and CO were 3.8, 12, and 64% higher in Bode than Chanban. The Kathmandu Valley thus has significant emissions from local sources, which can also be attributed to its bowl-shaped geography that is conducive to pollution build-up. At Bode, all three gas species (CO2, CH4, and CO) showed strong diurnal patterns in their mixing ratios with a pronounced morning peak (ca. 08:00), a dip in the afternoon, and a gradual increase again through the night until the next morning. CH4 and CO at Chanban, however, did not show any noticeable diurnal variations. These measurements provide the first insights into the diurnal and seasonal variation in key greenhouse gases and air pollutants and their local and regional sources, which is important information for atmospheric research in the region.
Y1  - 2017
U6  - https://doi.org/10.5194/acp-17-12573-2017
SN  - 1680-7316
SN  - 1680-7324
VL  - 17
IS  - 20
SP  - 12573
EP  - 12596
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Mahata, Khadak Singh
A1  - Rupakheti, Maheswar
A1  - Panday, Arnico Kumar
A1  - Bhardwaj, Piyush
A1  - Naja, Manish
A1  - Singh, Ashish
A1  - Mues, Andrea
A1  - Cristofanelli, Paolo
A1  - Pudasainee, Deepak
A1  - Bonasoni, Paolo
A1  - Lawrence, Mark
T1  - Observation and analysis of spatiotemporal characteristics of surface ozone and carbon monoxide at multiple sites in the Kathmandu Valley, Nepal
JF  - Atmosheric chemistry and physics
N2  - It was lower during the monsoon due to rainfall, which reduces open burning activities within the valley and in the surrounding regions and thus reduces sources of CO. The meteorology of the valley also played a key role in determining the CO mixing ratios. The wind is calm and easterly in the shallow mixing layer, with a mixing layer height (MLH) of about 250 m, during the night and early morning. The MLH slowly increases after sunrise and decreases in the afternoon. As a result, the westerly wind becomes active and reduces the mixing ratio during the daytime. Furthermore, there was evidence of an increase in the O-3 mixing ratios in the Kathmandu Valley as a result of emissions in the Indo-Gangetic Plain (IGP) region, particularly from biomass burning including agroresidue burning. A top-down estimate of the CO emission flux was made by using the CO mixing ratio and mixing layer height measured at Bode. The estimated annual CO flux at Bode was 4.9 mu g M-2 s(-1), which is 2-14 times higher than that in widely used emission inventory databases (EDGAR HTAP, REAS and INTEX-B). This difference in CO flux between Bode and other emission databases likely arises from large uncertainties in both the top-down and bottom-up approaches to estimating the emission flux. The O-3 mixing ratio was found to be highest during the premonsoon season at all sites, while the timing of the seasonal minimum varied across the sites. The daily maximum 8 h average O-3 exceeded the WHO recommended guideline of 50 ppb on more days at the hilltop station of Nagarkot (159 out of 357 days) than at the urban valley bottom sites of Paknajol (132 out of 354 days) and Bode (102 out of 353 days), presumably due to the influence of free-tropospheric air at the high-altitude site (as also indicated by Putero et al., 2015, for the Paknajol site in the Kathmandu Valley) as well as to titration of O-3 by fresh NOx emissions near the urban sites. More than 78 % of the exceedance days were during the premonsoon period at all sites. The high O-3 mixing ratio observed during the premonsoon period is of a concern for human health and ecosystems, including agroecosystems in the Kathmandu Valley and surrounding regions.
Y1  - 2018
U6  - https://doi.org/10.5194/acp-18-14113-2018
SN  - 1680-7316
SN  - 1680-7324
VL  - 18
IS  - 19
SP  - 14113
EP  - 14132
PB  - Copernicus
CY  - Göttingen
ER  -