DRY DEPOSITION of Aerosols above Forests in East Asia

Kazuhide Matsuda 한국대기환경학회 2014 한국대기환경학회 학술대회논문집 Vol.2014 No.10

Deposition Process of Sulfate and Elemental Carbon in Japanese and Thai Forests

Sase, Hiroyuki,Matsuda, Kazuhide,Visaratana, Thiti,Garivait, Hathairatana,Yamashita, Naoyuki,Kietvuttinon, Bopit,Hongthong, Bundit,Luangjame, Jesada,Khummongkol, Pojanie,Shindo, Junko,Endo, Tomomi,Sat Korean Society for Atmospheric Environment 2012 Asian Journal of Atmospheric Environment (AJAE) Vol.6 No.4

Particulate matter deposited on leaf surfaces may cause erosion/abrasion of epicuticular wax and the malfunction of stomata. However, the deposition processes of particulate matter, such as elemental carbon (EC), has not been studied sufficiently in Asian forest ecosystems. Deposition processes for particulate ${SO_4}^{2-}$ and EC were studied in a Japanese cedar forest in Kajikawa, Niigata Prefecture, Japan, and in a dry evergreen forest and a dry deciduous forest in Sakaerat, Nakhon Ratchasima province, Thailand. The ${SO_4}^{2-}$ fluxes attributed to rainfall outside the forest canopy (RF), throughfall (TF), and stemflow (SF) showed distinct seasonalities at both sites, increasing from November to February at the Kajikawa site and in March/April at the Sakaerat site. Seasonal west/northwest winds in winter may transport sulfur compounds across the Sea of Japan to the Kajikawa site. At the Sakaerat site, pollutants suspended in the air or dry deposits from the dry season might have been washed away by the first precipitations of the wet season. The EC fluxes from RF and TF showed similar variations by season at the Kajikawa site, while the flux from TF was frequently lower than that from RF at the Sakaerat site. Particulate matter strongly adsorbed onto leaf surfaces is not washed away by rainfall and contributes to the EC flux. At the Kajikawa site, Japanese cedar leaf surfaces accumulated the highest levels of particulate matter and could not be neglected when calculating the total flux. When such leaf-surface particles were considered, the contribution of dry deposition to the total EC flux was estimated to be 67%, 77%, and 82% at the Kajikawa site, and at the evergreen and deciduous forests of the Sakaerat site, respectively. Leaf-surface particles must be included when evaluating the dry and total fluxes of particulate matter, in particular for water-insoluble constituents such as EC.

Atmosphere-forest Exchange of Ammoniacal Nitrogen in a Subalpine Deciduous Forest in Central Japan during a Summer Week

Kentaro Hayashi,Kazuhide Matsuda,Akira Takahashi,Ko Nakaya 한국대기환경학회 2011 Asian Journal of Atmospheric Environment (AJAE) Vol.5 No.2

The present study aimed to investigate the diurnal variations in air concentrations and exchange fluxes of ammoniacal nitrogen (NHx: ammonia (NH_3) and particulate ammonium) in a subalpine deciduous forest in central Japan during a week in summer. The NH_3 concentrations (0.50 μg N m^-3 on average)showed a clear circadian variation, i.e., high and low in the daytime and nighttime, respectively. The concentration of particulate ammonium in the coarse fractions was extremely low, whereas that for the PM2.5 fraction was relatively high (0.55 μg N m^-3 on average). The main inorganic ion components of PM2.5 at the study site were ammonium and sulfate. The exchange fluxes of NHx were bidirectional. Both the maximum and minimum values occurred in the daytime, i.e., 0.39 mg N m^-2 hr^-1 of downward flux and 0.11 mg N m^-2 hr^-1 of upward flux for NH_3 and 0.25 mg N m^-2 hr^-1 of downward flux and 0.13 mg N m^-2 hr^-1 of upward flux for PM2.5 ammonium. The exchange fluxes of NHx at night could be considered as zero. The mean deposition velocity during the research period was almost zero for both NH_3 and PM2.5 ammonium. The atmosphere-forest exchange of NHx in the forest during the study period was balanced. The remarkably large deposition of NHx was attributable to meteorological events such as showers the night before that thoroughly washed the forest canopy and subsequent clear skies in the morning,which enhanced convection. The cleaning effect of rainfall and the rapid change in convection in the early morning should be monitored to evaluate and generalize the gas and particle exchange in a forest.

Deposition Process of Sulfate and Elemental Carbon in Japanese and Thai Forests

Hiroyuki Sase,Kazuhide Matsuda,Thiti Visaratana,Hathairatana Garivait,Naoyuki Yamashita,Bopit Kietvuttinon,Bundit Hongthong,Jesada Luangjame,Pojanie Khummongkol,Junko Shindo,Tomomi Endo,Keiichi Sato,S 한국대기환경학회 2012 Asian Journal of Atmospheric Environment (AJAE) Vol.6 No.4

Particulate matter deposited on leaf surfaces may cause erosion/abrasion of epicuticular wax and the malfunction of stomata. However, the deposition processes of particulate matter, such as elemental carbon (EC), has not been studied sufficiently in Asian forest ecosystems. Deposition processes for particulate SO42- and EC were studied in a Japanese cedar forest in Kajikawa, Niigata Prefecture, Japan, and in a dry evergreen forest and a dry deciduous forest in Sakaerat, Nakhon Ratchasima province, Thailand. The SO42- fluxes attributed to rainfall outside the forest canopy (RF), throughfall (TF), and stemflow (SF)showed distinct seasonalities at both sites, increasing from November to February at the Kajikawa site and in March/April at the Sakaerat site. Seasonal west/northwest winds in winter may transport sulfur compounds across the Sea of Japan to the Kajikawa site. At the Sakaerat site, pollutants suspended in the air or dry deposits from the dry season might have been washed away by the first precipitations of the wet season. The EC fluxes from RF and TF showed similar variations by season at the Kajikawa site, while the flux from TF was frequently lower than that from RF at the Sakaerat site. Particulate matter strongly adsorbed onto leaf surfaces is not washed away by rainfall and contributes to the EC flux. At the Kajikawa site, Japanese cedar leaf surfaces accumulated the highest levels of particulate matter and could not be neglected when calculating the total flux. When such leaf-surface particles were considered, the contribution of dry deposition to the total EC flux was estimated to be 67%, 77%, and 82% at the Kajikawa site,and at the evergreen and deciduous forests of the Sakaerat site, respectively. Leaf-surface particles must be included when evaluating the dry and total fluxes of particulate matter, in particular for waterinsoluble constituents such as EC.

Dry Deposition of PM2.5 Nitrate in a Forest according to Vertical Profile Measurements

Mao Xu,Kazuhide Matsuda 한국대기환경학회 2020 Asian Journal of Atmospheric Environment (AJAE) Vol.14 No.4

The atmospheric nitrogen compounds can serve as a nutrient; however, its excess deposition has harmful effects on terrestrial ecosystems due to acidification and eutrophication. There are still large uncertainties concerning the dry deposition process of PM2.5 nitrate in forests, even though this process affects the accuracy of chemical transport model simulations. To better understand this process, we conducted vertical profile measurements of inorganic ions in PM2.5 and SO2 above and within a forest canopy in the Field Museum Tamakyuryo site in suburban Tokyo with a particular focus on the processes observed under both daytime and nighttime and both leafy and leafless conditions. We performed two observations during leafy periods (July 21-August 1, 2015, and September 27-October 11, 2016) and one observation during a leafless period (February 23-29, 2016). To obtain daytime and nighttime vertical profiles, we set filter holders at 4 or 5 heights on an observation tower in the forest and changed the filters for each daytime and nighttime. For the PM2.5, the vertical gradients of NO3- concentration were larger than those of SO42- during both the daytime and nighttime for all observational periods, particularly during the leafy periods. In addition, the decreasing rate of NO3- in the PM2.5 within the canopy was larger than that of SO2 for some observational periods. In the daytime, the air temperature was higher near the canopy surface during the leafy period and near the ground surface during the leafless period. As also suggested by past studies, the large gradients of NO3 - in the PM2.5 during the leafy period were likely caused by the volatilization of NH4NO3 near the deposition surfaces due to the higher temperature in the daytime and the lower concentration of HNO3 caused by its fast removal during both the daytime and nighttime.

Characteristics of Atmosphere-rice Paddy Exchange of Gaseous and Particulate Reactive Nitrogen in Terms of Nitrogen Input to a Single-cropping Rice Paddy Area in Central Japan

Kentaro Hayashi,Keisuke Ono,Kazuhide Matsuda,Takeshi Tokida,Toshihiro Hasegawa 한국대기환경학회 2017 Asian Journal of Atmospheric Environment (AJAE) Vol.11 No.3

Nitrogen (N) is an essential macronutrient. Thus, evaluating its flows and stocks in rice paddy ecosystems provides important insights into the sustainability and environmental loads of rice production. Among the N sources of paddy fields, atmospheric deposition and irrigation inputs remain poorly understood. In particular, insufficient information is available for atmosphere-rice paddy exchange of gaseous and particulate reactive N (Nr, all N species other than molecular N) which represents the net input or output through dry deposition and emission. In this study, we assessed the N inputs via atmospheric deposition and irrigation to a Japanese rice paddy area by weekly monitoring for 2 years with special emphasis on gas and particle exchange. The rice paddy during the cropping season acted as a net emitter of ammonia (NH3) to the atmosphere regardless of the N fertilizer applications, which reduced the effects of dry deposition to the N input. Dry N deposition was quantitatively similar to wet N deposition, when subtracting the rice paddy NH3 emissions from N exchange. The annual N inputs to the rice paddy were 3.2 to 3.6 kg N ha-1 yr-1 for exchange, 8.1 to 9.8 kg N ha-1 yr-1 for wet deposition, and 11.1 to 14.5 kg N ha-1 yr-1 for irrigation. The total N input, 22.8 to 27.5 kg N ha-1 yr-1, corresponded to 38% to 55% of the N fertilizer application rate and 53% to 67% of the brown rice N uptake. Monitoring of atmospheric deposition and irrigation as N sources for rice paddies will therefore be necessary for adequate N management.

Cacao bean husk: an applicable bedding material in dairy free-stall barns

Akira Yajima,Hisashi Owada,Suguru Kobayashi,Natsumi Komatsu,Kazuaki Takehara,Maria Ito,Kazuhide Matsuda,Kan Sato,Hisao Itabashi,Satoshi Sugimura,Shuhei Kanda 아세아·태평양축산학회 2017 Animal Bioscience Vol.30 No.7

Objective: The objectives of the study were to assess the effect of cacao bean husk as bedding material in free-stall barn on the behavior, productivity, and udder health of dairy cattle, and on the ammonia concentrations in the barn. Methods: Four different stall surfaces (no bedding, cacao bean husk, sawdust, and chopped wheat straw) were each continuously tested for a period of 1 week to determine their effects on nine lactating Holstein cows housed in the free-stall barn with rubber matting. The lying time and the milk yield were measured between d 4 and d 7. Blood samples for plasma cortisol concentration and teat swabs for bacterial counts were obtained prior to morning milking on d 7. The time-averaged gas-phase ammonia concentrations in the barn were measured between d 2 and d 7. Results: The cows spent approximately 2 h more per day lying in the stalls when bedding was available than without bedding. The milk yield increased in the experimental periods when cows had access to bedding materials as compared to the period without bedding. The lying time was positively correlated with the milk yield. Bacterial counts on the teat ends recorded for cows housed on cacao bean husk were significantly lower than those recorded for cows housed without bedding. Ammonia concentration under cacao bean husk bedding decreased by 6%, 15%, and 21% as compared to no bedding, sawdust, and chopped wheat straw, respectively. The cortisol concentration was lowest in the period when cacao bean husk bedding was used. We observed a positive correlation between the ammonia concentrations in the barn and the plasma cortisol concentrations. Conclusion: Cacao bean husk is a potential alternative of conventional bedding material, such as sawdust or chopped wheat straw, with beneficial effects on udder health and ammonia concentrations in the barns.