We have updated the Regional Emission inventory in ASia (REAS) as version 2.1. REAS 2.1 includes most major air pollutants and greenhouse gases from each year during 2000 and 2008 and following areas ...of Asia: East, Southeast, South, and Central Asia and the Asian part of Russia. Emissions are estimated for each country and region using updated activity data and parameters. Monthly gridded data with a 0.25° × 0.25° resolution are also provided. Asian emissions for each species in 2008 are as follows (with their growth rate from 2000 to 2008): 56.9 Tg (+34%) for SO2, 53.9 Tg (+54%) for NOx, 359.5 Tg (+34%) for CO, 68.5 Tg (+46%) for non-methane volatile organic compounds, 32.8 Tg (+17%) for NH3, 36.4 Tg (+45%) for PM10, 24.7 Tg (+42%) for PM2.5, 3.03 Tg (+35%) for black carbon, 7.72 Tg (+21%) for organic carbon, 182.2 Tg (+32%) for CH4, 5.80 Tg (+18%) for N2O, and 16.0 Pg (+57%) for CO2. By country, China and India were respectively the largest and second largest contributors to Asian emissions. Both countries also had higher growth rates in emissions than others because of their continuous increases in energy consumption, industrial activities, and infrastructure development. In China, emission mitigation measures have been implemented gradually. Emissions of SO2 in China increased from 2000 to 2006 and then began to decrease as flue-gas desulphurization was installed to large power plants. On the other hand, emissions of air pollutants in total East Asia except for China decreased from 2000 to 2008 owing to lower economic growth rates and more effective emission regulations in Japan, South Korea, and Taiwan. Emissions from other regions generally increased from 2000 to 2008, although their relative shares of total Asian emissions are smaller than those of China and India. Tables of annual emissions by country and region broken down by sub-sector and fuel type, and monthly gridded emission data with a resolution of 0.25° × 0.25° for the major sectors are available from the following URL: http://www.nies.go.jp/REAS/.
We developed a new emission inventory for Asia (Regional Emission inventory in ASia (REAS) Version 1.1) for the period 1980–2020. REAS is the first inventory to integrate historical, present, and ...future emissions in Asia on the basis of a consistent methodology. We present here emissions in 2000, historical emissions for 1980–2003, and projected emissions for 2010 and 2020 of SO2, NOx, CO, NMVOC, black carbon (BC), and organic carbon (OC) from fuel combustion and industrial sources. Total energy consumption in Asia more than doubled between 1980 and 2003, causing a rapid growth in Asian emissions, by 28% for BC, 30% for OC, 64% for CO, 108% for NMVOC, 119% for SO2, and 176% for NOx. In particular, Chinese NOx emissions showed a marked increase of 280% over 1980 levels, and growth in emissions since 2000 has been extremely high. These increases in China were mainly caused by increases in coal combustion in the power plants and industrial sectors. NMVOC emissions also rapidly increased because of growth in the use of automobiles, solvents, and paints. By contrast, BC, OC, and CO emissions in China showed decreasing trends from 1996 to 2000 because of a reduction in the use of biofuels and coal in the domestic and industry sectors. However, since 2000, Chinese emissions of these species have begun to increase. Thus, the emissions of air pollutants in Asian countries (especially China) showed large temporal variations from 1980–2003. Future emissions in 2010 and 2020 in Asian countries were projected by emission scenarios and from emissions in 2000. For China, we developed three emission scenarios: PSC (policy success case), REF (reference case), and PFC (policy failure case). In the 2020 REF scenario, Asian total emissions of SO2, NOx, and NMVOC were projected to increase substantially by 22%, 44%, and 99%, respectively, over 2000 levels. The 2020 REF scenario showed a modest increase in CO (12%), a lesser increase in BC (1%), and a slight decrease in OC (−5%) compared with 2000 levels. However, it should be noted that Asian total emissions are strongly influenced by the emission scenarios for China.
We examine contributions from various source regions to global distributions and budgets of tropospheric ozone (O3) in the context of intercontinental transport, using tagged tracer simulation with a ...global chemical transport model. For tagging O3, we consider regional separation of the model domain on the basis of the distributions of O3 chemical production. We define 14 polluted source regions (14 tracers) in the boundary layer (North America, Europe, China, etc.) and 8 regions (8 tracers) in the free troposphere; O3 production in the remaining (remote) tropospheric region and O3 transport from the stratosphere are also tagged as separate tracers. O3 transport from the polluted source regions like North America, Europe, and Asia generally accounts for more than 40% of ozone abundances even in remote locations. O3 exports from boundary layer in China and Asian free troposphere are discerned through much of the Northern Hemisphere, suggesting significant and extensive impacts of eastern Asian pollution. In particular, O3 from Asian free troposphere plays the most important roles in distribution and seasonal variation of O3 in the middle‐upper troposphere almost globally. In June–September, the model calculates a large O3 contribution (5–10 ppbv) from Asian free troposphere in the upper troposphere over the South Pacific associated with long‐range interhemispheric transport from Asia to the southern midlatitudes (via the western Indian Ocean, Africa, and Atlantic) in the upper troposphere. O3 transported from biomass burning regions such as South America, Africa, and Australia widely distributes in the Southern Hemisphere. Our simulation demonstrates that there is a significant interhemispheric O3 transport from South America to the northern midlatitudes in the upper troposphere which reaches Japan, North Pacific, and the United States in conjunction with O3 export from North Africa. Our tagged O3 simulation estimates that the annual mean global tropospheric O3 burden, as calculated to be 344 Tg in this study, comes from chemical production in the source regions (48%) and in the remote regions (29%) and from stratosphere‐troposphere exchange (23%).
A methodology for the collection and analysis of organic carbon (OC) and elemental carbon (EC) in precipitation was established and the monitoring of OC and EC in precipitation and aerosol was ...implemented at the Niigata (rural), Sado (remote), and Tokyo (urban) sites in Japan. The OC in precipitation was measured for water-insoluble OC (WIOC) and water-soluble OC (WSOC) separately. The concentrations of EC and WIOC in precipitation were 78.9 μg/l and 657 μg/l at the Tokyo site, 26.0 μg/l and 274 μg/l at the Sado site, 24.6 μg/l and 274 at the Niigata site. The ratio of EC to OC in the precipitation and aerosol samples were the highest at Tokyo site. The scavenging ratio of OC was higher than EC, implying that OC was more easily removed from the atmosphere compared to EC. The high concentrations of EC in precipitation in winter and spring at the Sado site were mainly due to the long-range transport from the Northeast Asian Continent, whereas at the Tokyo site the high level of EC concentration was mainly from domestic emissions. The seasonal variation of EC and OC in precipitation in East Asia was obtained for the first time. The major source for the high EC concentrations in precipitation at the Sado site in winter was ascribed to the fuel combustion, but in spring, it may be the result of biomass burning in the Northeast of the continent.
•The establishment of methodology for collection and analysis of carbonaceous aerosol in precipitation.•The first long-term monitoring data of wet deposition of carbonaceous components in East Asia.•Comparison of characteristics of carbonaceous components in precipitation and atmospheric particle at representative sites.•Discussion of seasonal variation of carbonaceous components in precipitation and influence of long range transport.
Some indices of food texture were not enough to reproduce the kinetic energy. Therefore, we developed a device and an index (Energy Texture Index, ETI) that enables one to measure the kinetic energy ...of vibration by the food fracture using a probe mass obtained by a free running. It enabled one to define another index (Food Friction Index, FFI) that was also proposed to measure a friction of probe against a food sample. The ETI and FFI were measured for apple, persimmon, and banana as examples. The ETI and FFI showed a characteristic difference between the three fruit samples. The FFI was found to be constant even if the insertion velocity into sample is changed. The ETI and FFI have possibilities to show a new facet of food texture.
•A new device with a free running probe was developed to measure kinetic energy of acoustic vibration on rapture of food.•A new Energy Texture Index (ETI) to estimate the kinetic energy was defined.•The free running of probe enabled one to define another Food Friction Index (FFI) of a food sample.•The ETI and FFI unveiled facets characteristic of food texture.
Aerosols in the troposphere influence photolysis frequencies and hence the concentrations of chemical species. We used a three-dimensional regional chemical transport model (NAQPMS) coupled with an ...accurate radiative transfer model to examine the impacts of aerosols on summertime photochemistry in Central Eastern China (CEC)
via changing photolysis frequencies. In addition to looking at changes in concentrations as previous studies have done, we examined the changes in ozone (O
3) budgets and the uncertainties related to our estimations. The 1st–12th June 2006 was selected as the simulation period when high aerosol optical depth at 550
nm (AOD550) and O
3 were found. A comparison of measurements showed that the model was capable of reproducing the spatial and temporal variations in photolysis frequencies, ultraviolet (UV) radiation, AOD550, cloud optical depth, O
3 and other chemical constitutes in CEC. Aerosols have important impacts on atmospheric oxidation capacity in CEC. On a regional scale, aerosols decreased the average O
3→O (
1D) photolysis frequency by 53%, 37% and 21% in the lower, middle and upper troposphere in CEC. The uncertainties of these estimations were 37%, 25% and 14%, respectively. Mean OH concentrations decreased by 51%, 40% and 24% in layers below 1
km, 1–3
km and 3–10
km, with uncertainties of 39%, 28% and 9%, respectively. The changes in HO
2 concentrations were smaller but significant. In contrast, NO
x showed a significant increase at 0–1
km and 1–3
km in CEC, with magnitudes of 6% and 8%. The largest relative enhancement occurred in downwind regions below 1
km. Summertime boundary layer O
3 (below 1
km and 1–3
km) was reduced by 5% with a maximum of 9% in highly polluted regions. The reduced ozone production (P (O
3)) was responsible for this reduction below 3
km.
► A 3D chemical transport model was coupled with an accurate radiative transfer model. ► The siginificant impacts of aerosols on summertime photochemistry in Central China. ► Summertime boundary layer ozone reduced by 5% in polluted regions.
We estimated the source-receptor relationship for surface O3 in East Asia during the early 2000s using a method that tags O3 tracers according to their region of chemical production (tagged tracer ...method) with a global chemical transport model. The estimation demonstrated the importance of intracontinental transport of O3 inside East Asia as well as of the transport of O3 from distant source regions. The model well simulated the absolute concentration and seasonal variation of surface O3 in East Asia and demonstrated significant seasonal differences in the origin of surface O3. In the cold season (October to March), more than half of surface O3 in East Asia is attributable to the O3 transported from distant sources outside of East Asia. In the warm season (April to September), most of the surface O3 is attributable to O3 created within East Asia in most areas of East Asia. In spring the contribution of domestically created O3 accounted for 20% of the surface O3 in Japan and the Korean Peninsula, 40% in the North China Plain, and around 50% in the southern part of China, and the domestic contribution increased greatly in summer. The contributions of O3 created in China and the Korean Peninsula to O3 in Japan were estimated at about 10% and 5%, respectively. We also demonstrated a large contribution (20%) from China to the Korean Peninsula. In the northern and southern parts of China, large contributions of over 10% from East Siberia and the Indochina Peninsula, respectively, were identified. The contribution from intercontinental transport increased with latitude; it was 21% in Northeast China and 13% in Japan and the Korean Peninsula in spring. As for the hourly mean of surface O3, domestically created O3 was the main contributor in most areas of East Asia, except for the low O3 class (<30 ppbv), and accounted for more than 50% in the very high O3 class (>90 ppbv). The mean relative contribution of O3 created in China to O3 in central Japan was about 10% in every class, but that created in the Korean Peninsula was significant in all except the low O3 class. We identified the substantial impact of foreign sources on Japan's ambient air quality standard in the high O3 class (60–90 ppbv) in spring.
We conducted long-term network observations using standardized Multi-Axis Differential optical absorption spectroscopy (MAX-DOAS) instruments in Russia and ASia (MADRAS) from 2007 onwards and made ...the first synthetic data analysis. At seven locations (Cape Hedo, Fukue and Yokosuka in Japan, Hefei in China, Gwangju in Korea, and Tomsk and Zvenigorod in Russia) with different levels of pollution, we obtained 80 927 retrievals of tropospheric NO2 vertical column density (TropoNO2VCD) and aerosol optical depth (AOD). In the technique, the optimal estimation of the TropoNO2VCD and its profile was performed using aerosol information derived from O4 absorbances simultaneously observed at 460–490 nm. This large data set was used to analyze NO2 climatology systematically, including temporal variations from the seasonal to the diurnal scale. The results were compared with Ozone Monitoring Instrument (OMI) satellite observations and global model simulations. Two NO2 retrievals of OMI satellite data (NASA ver. 2.1 and Dutch OMI NO2 (DOMINO) ver. 2.0) generally showed close correlations with those derived from MAX-DOAS observations, but had low biases of up to ~50%. The bias was distinct when NO2 was abundantly present near the surface and when the AOD was high, suggesting a possibility of incomplete accounting of NO2 near the surface under relatively high aerosol conditions for the satellite observations. Except for constant biases, the satellite observations showed nearly perfect seasonal agreement with MAX-DOAS observations, suggesting that the analysis of seasonal features of the satellite data were robust. Weekend reduction in the TropoNO2VCD found at Yokosuka and Gwangju was absent at Hefei, implying that the major sources had different weekly variation patterns. While the TropoNO2VCD generally decreased during the midday hours, it increased exceptionally at urban/suburban locations (Yokosuka, Gwangju, and Hefei) during winter. A global chemical transport model, MIROC-ESM-CHEM (Model for Interdisciplinary Research on Climate–Earth System Model–Chemistry), was validated for the first time with respect to background NO2 column densities during summer at Cape Hedo and Fukue in the clean marine atmosphere.
A 3-D regional chemical transport model, the Nested Air Quality Prediction Model System (NAQPMS), with an on-line tracer tagging module was used to study the source of the near-ground (<1.5 km above ...ground level) ozone at Mt. Tai (36.25° N, 117.10° E, 1534 m a.s.l.) in Central Eastern China (CEC) during the Mount Tai eXperiment 2006 (MTX2006). The model reproduced the temporal and spatial variations of near-ground ozone and other pollutants, and it captured highly polluted and clean cases well. The simulated near-ground ozone level over CEC was 60–85 ppbv (parts per billion by volume), which was higher than values in Japan and over the North Pacific (20–50 ppbv). The simulated tagged tracer data indicated that the regional-scale transport of chemically produced ozone over other areas in CEC contributed to the greatest fraction (49%) of the near-ground mean ozone at Mt. Tai in June; in situ photochemistry contributed only 12%. Due to high anthropogenic and biomass burning emissions that occurred in the southern part of the CEC, the contribution to ground ozone levels from this area played the most important role (32.4 ppbv, 37.9% of total ozone) in the monthly mean ozone concentration at Mt. Tai; values reached 59 ppbv (62%) on 6–7 June 2006. The monthly mean horizontal distribution of chemically produced ozone from various ozone production regions indicated that photochemical reactions controlled the spatial distribution of O3 over CEC. The regional-scale transport of pollutants also played an important role in the spatial and temporal distribution of ozone over CEC. Chemically produced ozone from the southern part of the study region can be transported northeastwardly to the northern rim of CEC; the mean contribution was 5–10 ppbv, and it reached 25 ppbv during high ozone events. Studies of the outflow of CEC ozone and its precursors, as well as their influences and contributions to the ozone level over adjacent regions/countries, revealed that the contribution of CEC ozone to mean ozone mixing ratios over the Korean Peninsula and Japan was 5–15 ppbv, of which about half was due to the direct transport of ozone from CEC and half was produced locally by ozone precursors transported from CEC.
HO2 uptake coefficients for ambient aerosol particles, collected on quartz fiber filter using a high-volume air sampler in China, were measured using an aerosol flow tube coupled with a chemical ...conversion/laser-induced fluorescence technique at 760 Torr and 298 K, with a relative humidity of 75%. Aerosol particles were regenerated with an atomizer using the water extracts from the aerosol particles. Over 10 samples, the measured HO2 uptake coefficients for the aerosol particles at the Mt. Tai site were ranged from 0.13 to 0.34, while those at the Mt. Mang site were in the range of 0.09-0.40. These values are generally larger than those previously reported for single-component particles, suggesting that reactions with the minor components such as metal ions and organics in the particle could contribute to the HO2 uptake. A box model calculation suggested that the heterogeneous loss of HO2 by ambient particles could significantly affect atmospheric HOx concentrations and chemistry.
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