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A long-term historical emission inventory of air and climate pollutants in East, Southeast, and South Asia during 1950–2015 was developed as the Regional Emission inventory in ASia version 3 (REASv3). REASv3 provides details of emissions from major anthropogenic sources for each country and its sub-regions and also provides monthly gridded data with 0.25∘ × 0.25∘ resolution. The average total emissions in Asia during 1950–1955 and during 2010–2015 (growth rates in these 60 years estimated from the two averages) are as follows: SO2: 3.2 Tg, 42.4 Tg (13.1); NOx: 1.6 Tg, 47.3 Tg (29.1); CO: 56.1 Tg, 303 Tg (5.4); non-methane volatile organic compounds: 7.0 Tg, 57.8 Tg (8.3); NH3: 8.0 Tg, 31.3 Tg (3.9); CO2: 1.1 Pg, 18.6 Pg (16.5) (CO2 excluding biofuel combustion 0.3 Pg, 16.8 Pg (48.6)); PM10: 5.9 Tg, 30.2 Tg (5.1); PM2.5: 4.6 Tg, 21.3 Tg (4.6); black carbon: 0.69 Tg, 3.2 Tg (4.7); and organic carbon: 2.5 Tg, 6.6 Tg (2.7). Clearly, all the air pollutant emissions in Asia increased significantly during these 6 decades, but situations were different among countries and regions. Due to China's rapid economic growth in recent years, its relative contribution to emissions in Asia has been the largest. However, most pollutant species reached their peaks by 2015, and the growth rates of other species were found to be reduced or almost zero. On the other hand, air pollutant emissions from India showed an almost continuous increasing trend. As a result, the relative ratio of emissions of India to that of Asia has increased recently. The trend observed in Japan was different from the rest of Asia. In Japan, emissions increased rapidly during the 1950s–1970s, which reflected the economic situation of the period; however, most emissions decreased from their peak values, which were approximately 40 years ago, due to the introduction of control measures for air pollution. Similar features were found in the Republic of Korea and Taiwan. In the case of other Asian countries, air pollutant emissions generally showed an increase along with economic growth and motorization. Trends and spatial distribution of air pollutants in Asia are becoming complicated. Data sets of REASv3, including table of emissions by countries and sub-regions for major sectors and fuel types, and monthly gridded data with 0.25∘ × 0.25∘ resolution for major source categories are available through the following URL: https://www.nies.go.jp/REAS/index.html (last access: 31 October 2020).

This study presents the results of the ERTDF S-12 project for searching an optimum reduction scenario of the short-lived climate pollutants (SLCPs) to simultaneously mitigate the global warming and environmental problems. The study utilized REAS emission inventory, Asia-Pacific Integrated Model-Enduse (AIM/Enduse), MIROC6 climate model, NICAM non-hydrostatic atmospheric model, and models for estimating environmental damages to health, agriculture, and flood risks. Results of various scenario search indicate that it is difficult to attain simultaneous reduction of global warming and environmental damages, unless a significant reduction of CO2 is combined with carefully designed SLCP reductions for CH4, SO2, black carbon (BC), NOx, CO, and VOCs. In this scenario design, it is important to take into account the impact of small BC reduction to the surface air temperature and complex atmospheric chemical interactions such as negative feedback between CH4 and NOx reduction. We identified two scenarios, i.e., B2a and B1c scenarios which combine the 2D-scenario with SLCP mitigation measures using End-of-Pipe (EoP) and new mitigation technologies, as promising to simultaneously mitigate the temperature rise by about 0.33 °C by 2050 and air pollution in most of the globe for reducing damages in health, agriculture, and flood risk. In Asia and other heavy air pollution areas, health-care measures have to be enhanced in order to suppress the mortality increase due to high temperature in hot spot areas caused by a significant cut of particulate matter. For this situation, the B1b scenario is better to reduce hot spot areas and high-temperature damage to the public health.

The MIX inventory is developed for the years 2008 and 2010 to support the Model Inter-Comparison Study for Asia (MICS-Asia) and the Task Force on Hemispheric Transport of Air Pollution (TF HTAP) by a mosaic of up-to-date regional emission inventories. Emissions are estimated for all major anthropogenic sources in 29 countries and regions in Asia. We conducted detailed comparisons of different regional emission inventories and incorporated the best available ones for each region into the mosaic inventory at a uniform spatial and temporal resolution. Emissions are aggregated to five anthropogenic sectors: power, industry, residential, transportation, and agriculture. We estimate the total Asian emissions of 10 species in 2010 as follows: 51.3 Tg SO2, 52.1 Tg NOx, 336.6 Tg CO, 67.0 Tg NMVOC (non-methane volatile organic compounds), 28.8 Tg NH3, 31.7 Tg PM10, 22.7 Tg PM2.5, 3.5 Tg BC, 8.3 Tg OC, and 17.3 Pg CO2. Emissions from China and India dominate the emissions of Asia for most of the species. We also estimated Asian emissions in 2006 using the same methodology of MIX. The relative change rates of Asian emissions for the period of 2006–2010 are estimated as follows: −8.1 % for SO2, +19.2 % for NOx, +3.9 % for CO, +15.5 % for NMVOC, +1.7 % for NH3, −3.4 % for PM10, −1.6 % for PM2.5, +5.5 % for BC, +1.8 % for OC, and +19.9 % for CO2. Model-ready speciated NMVOC emissions for SAPRC-99 and CB05 mechanisms were developed following a profile-assignment approach. Monthly gridded emissions at a spatial resolution of 0.25° × 0.25° are developed and can be accessed from http://www.meicmodel.org/dataset-mix.

Air pollutants such as tropospheric ozone and PM2.5 travel through large areas. The damage factors (DFs) presented by existing researches in life cycle impact assessment do not take into consideration transboundary movement. A previous study used a global chemistry transport model (CTM), to develop health damage factors for ten different regions around the world by considering the transboundary movement of PM2.5. Under the same assessment procedure, this research is designed to calculate the ozone DFs by region and to find the effects of wide range movement on the DFs. The DFs by regions are defined as changes in disability-adjusted life years (DALYs) derived from changes in tropospheric ozone concentration around the world which is induced by an increase in emissions of the unit amount of nitrogen oxides (NOx) and non-methane volatile organic compounds (NMVOC). DFs for ten regions are calculated as follows. Firstly, the concentration change of worldwide ozone caused by a change in emission of a substance from one region is estimated with a global scale CTM for both NOx and NMVOC. Secondly, DALY changes on the world due to a change in concentration of ozone are estimated by using population data and epidemiological concentration-response functions for mortality and morbidity. Finally, the above calculations are done for all targeted ten regions. DFs of NOx and NMVOC for ten regions were calculated as 0.3–4.2 × 10−5 DALY/kg and 0.2–5.6 × 10−6 DALY/kg, respectively. It was found DFs might be underestimated around 10 to 70 % by region if the transboundary movement is not taken into consideration. In many regions in the northern hemisphere, about 60 % of damage occurs outside the emission area, which is larger than that of southern hemispheric regions due to a larger population exposed to downwind places. In regions of China and India, however, the influence on other regions accounted for only 10 % because these regions involve larger influences in the source region. The impact of NO titration effect can be seen in cold seasons in many regions, but it was found that the effect is remarkable on an annual average only in Europe, a cold region with large emissions. The human health DFs of NOx and NMVOC considering effects of transboundary movement of tropospheric ozone are estimated for ten regions by using a global CTM. As a future work, it is important to show the interannual sensitivity of the DFs through chronological assessments.

This chapter provides an analysis of the urban pollution and potential for co-benefits in India, making a comparison with other South Asian countries. Most of the South Asian countries are at the stage of developing or emerging economies, and India is the fastest growing economy among them. The Indian subcontinent is comprised of hundreds of densely populated large and medium size cities including five megacities (each with a population of more than 10 million). Constantly increasing energy-intensive urban activities in burgeoning cities and biomass burning in rural areas of India are responsible for a large share in the unacceptably high emissions of health-endangering and environment-polluting gaseous and particulate pollutants. The air pollution problem in India and the rest of the South Asia came into the spotlight by the South Asian haze called the Atmospheric Brown Cloud (ABC), which is said to be responsible for annually 100,000s premature deaths in the South Asian region (Lelieveld et al. 2001). Given the increasing trend of energy use and emissions in Indian cities, the present study is a step to make governments and people aware of the extent and intensity of the ambient as well as the indoor air pollution problem. The analysis presented in this study is expected to help initiate appropriate policy measures and suitable action plans to limit emissions and adopt ways based on the co-benefits approach that promote sustainable development.

A better understanding of land cover/land use changes (LCLUC) and their interactions with the atmospheric environment is essential for the sustainable management of natural resources, environmental protection, air quality, agricultural planning and food security. The 15 papers published in this focus issue showcase a variety of studies relating to drivers and impacts of LCLUC and air pollution in different South/Southeast Asian (S/SEA) countries. This synthesis article, in addition to giving context to the articles in this focus issue, also reviews the broad linkages between population, LCLUC and air pollution. Additionally, we identify knowledge gaps and research priorities that are essential in addressing air pollution issues in the region. We conclude that for effective pollution mitigation in S/SEA countries, quantifying drivers, sources and impacts of pollution need a thorough data analysis through ground-based instrumentation, models and integrated research approaches. We also stress the need for the development of sustainable technologies and strengthening the scientific and resource management communities through capacity building and training activities to address air pollution issues in S/SEA countries.

Air pollution is widely understood to be capable of exacerbating asthma symptoms. Here we examined the association between traffic-related air pollution and development of asthma in school children. Subjects were 10,069 school children in their first through third years of compulsory education (6-9-year old). The main outcome was incidence of asthma as determined from the questionnaire. Follow-up surveys were conducted every year up to 4 years after the end of the study. To evaluate individual level of exposure to traffic-related air pollution, we used a simulation model that accounted for exposure level both at home and at school. As surrogates of traffic-related air pollution, the estimation target was the annual average individual exposure of automobile exhaust-originating nitrogen oxides (NOx) and elemental carbon (EC). Confounding factors were adjusted using a discrete-time logistic regression model. We found a positive association between exposure to EC and incidence of asthma. The odds ratio (OR) (95% confidence interval) for asthma incidence was 1.07 (1.01-1.14) for each 0.1 μg/m(3) EC and 1.01 (0.99-1.03) for each 1 p.p.b. NOx. Traffic-related air pollution is associated with development of asthma in school children.

In winter 2013, extreme air pollution by fine particulate matter (PM 2.5 ) in China attracted much public attention. In order to simulate the PM 2.5 pollution, the Community Multiscale Air Quality model driven by the Weather Research and Forecasting model was applied to East Asia in a period from 1 January 2013 to 5 February 2013. The model generally reproduced PM 2.5 concentration in China with emission data in the year 2006. Therefore, the extreme PM 2.5 pollution seems to be mainly attributed to meteorological (weak wind and stable) conditions rather than emission increases in the past several years. The model well simulated temporal and spatial variations in PM 2.5 concentrations in Japan as well as China, indicating that the model well captured characteristics of the PM 2.5 pollutions in both areas on the windward and leeward sides in East Asia in the study period. In addition, contribution rates of four anthropogenic emission sectors (power generation, industrial, residential and transportation) in China to PM 2.5 concentration were estimated by conducting zero-out emission sensitivity runs. Among the four sectors, the residential sector had the highest contribution to PM 2.5 concentration. Therefore, the extreme PM 2.5 pollution may be also attributed to large emissions from combustion for heating in cold regions in China.

We analyzed the source–receptor relationships for particulate polycyclic aromatic hydrocarbon (PAH) concentrations in northeastern Asia using an aerosol chemical transport model. The model successfully simulated the observed concentrations. In Beijing (China) benzo[a]pyren (BaP) concentrations are due to emissions from its own domain. In Noto, Oki and Tsushima (Japan), transboundary transport from northern China (>40°N, 40–60%) and central China (30–40°N, 10–40%) largely influences BaP concentrations from winter to spring, whereas the relative contribution from central China is dominant (90%) in Hedo. In the summer, the contribution from Japanese domestic sources increases (40–80%) at the 4 sites. Contributions from Japan and Russia are additional source of BaP over the northwestern Pacific Ocean in summer. The contribution rates for the concentrations from each domain are different among PAH species depending on their particulate phase oxidation rates. Reaction with O3 on particulate surfaces may be an important component of the PAH oxidation processes.

Objectives: There has been little study on the effect of traffic-related air pollution on the incidence and persistence of asthma in preschool children. We evaluated the association of exposure to traffic-related air pollution with the incidence/persistence of asthma during the first 3 years of life using a population-based study. Methods: A baseline survey was conducted in 1 1/2-year-old children (n=63 266). A follow-up survey at 3 years of age (n=43 343) identified new-onset asthma cases (n=853) and persistence of asthma (n=214). In the prevalence/persistence study, the outdoor concentrations of nitrogen oxides (NOx) and elemental carbon (EC) at home during the first 1 1/2 years of life were estimated by a dispersion model. In the nested case-control study, which regarded incidence of asthma as cases, the personal exposure levels were estimated by dispersion model including time-activity pattern. Results: There was no statistically significant association between the incidence of asthma between age 1 1/2 and 3 years and personal exposure levels to NOx nor EC. However, the persistence of asthmatic symptoms (between 1 1/2 and 3 years) was significantly associated with outdoor concentrations of NOx. ORs for the persistence of asthmatic symptoms were 6.02 (95% CI 1.51 to 23.92) for the comparison between the upper 5th and lower 25th centiles of NOx. Conclusions: While no statistically significant association was observed for the incidence of asthma, the persistence of asthmatic symptoms in preschool children was significantly associated with traffic-related air pollution. This supports its importance as a risk factor in childhood airway disease.

We evaluate the performance of reduced-scale wind-tunnel experiments that simulate vehicle-induced pollutant diffusion in urban roadside area. From Japanese urban areas, we selected four sites that cover a wide range of road structures, building density, and roadside features. At each site, four field stations were installed to monitor concentration of air pollutants including nitrogen oxides (NOx). In the wind-tunnel experiments, ethane was emitted from along the major roads, and its concentration was compared with the background-subtracted field values. For annual average of NOx in the year 2006, we found that an appropriately normalized concentration agreed fairly well between wind-tunnel and field measurements. The wind-tunnel concentration distribution measured at a high spatial resolution revealed that roadside features such as tall buildings, noise barriers, and trees have considerable effect on the concentration on the downwind or upwind side of the roads. The high-resolution results are expected to serve as a useful database for evaluating numerical air pollution models.

We studied trends in Asian air pollution in recent decades using air-quality monitoring station data, satellite retrieval data (GOME NO2), and regional-scale chemical transport model (CTM) simulation. A newly developed annual Asian-scale emission inventory (REAS) from 1980-2003 was used in observation data analysis and CTM. Analyses of recent trends in annual emissions in China by REAS and satellite GOME NO2 show an 8-10% increase after 2000 suggesting the impact of long-range transport of secondary air pollutants in regions and countries downwind. Detailed analyses of O3 observation data in Japan suggest an annual averaged O3 concentration increase of 2% yr-1 due to this long-range transport. We extended our regional air quality study targeting 2020. REAS provides three emission scenarios for China: the reference case (REF), the policy success case (PSC), and the policy failure case (PFC). Projected REF emissions for 2020 show O3 concentrations rising to 75 to 90 ppbv in June and 75 to 85 ppbv in August over the North China Plain. Projected PFC emissions bring an increase of monthly averaged O3 with greater than 20 ppbv (1 ppbv yr-1 growth) in the North China Plain. Surface O3 under the PFC scenario is enhanced by 6 to 8 ppbv over the Korean Peninsula and by 2 to 6 ppbv in Japan from 2000 to 2020 despite the reduction of NOx in Japan. This may become a critical level in air quality in Asia.

There is substantial difference in the coal consumption data in China during 1996–2003 among the three official energy statistics; the province-by-province data in the China Energy Statistics Yearbook (PBP-CESY), the energy balance tables by International Energy Agency (IEA2004) [2004, Energy Statistics of Non-OECD Countries. IEA, Paris], and the country-total data in the China Energy Statistics Yearbook (CT-CESY). Verification of these data was made by GOME satellite observational data for tropospheric NO2 column density in Northern China Plain reported by Irie et al. [2005, Evaluation of long-termtropospheric NO2 data obtained by GOME over East Asia in 1996–2002. Geophysical Research Letter 32(11), L11810, doi: 10.1029/2005GL022770] and Richter et al. [2005, Increase in tropospheric nitrogen dioxide over China observed from space. Nature 437, 129–130]. The NO2 column increase from 1996 to 2002 averaged for the two reports is about 50%, whereas the NOx emission increases based on the PBP-CESY and IEA2004 are 25% and 15%, respectively, and that for CT-CESY is even lower. The discrepancy of the increasing trends between the satellite data and the PBP-CESY emission inventory could be within the uncertainty level with a reservation that the increase in total fuel consumption in PBP-CESY may still be underestimated particularly after the year of 1999. The increasing rates of NOx emissions during 1996–2002 calculated by using the IEA2004 and CT-CESY statistics are apparently underestimated beyond the uncertainty level of the satellite observation, and they are recommended not to be used for emission inventory studies in China during the period.

To assess the contribution of biomass burning to the emissions of atmospheric trace species in China, we estimated various biomass-burning activities using statistical data, survey data, expert estimates and a satellite data set. Fuel wood and crop residue burned as fuel and in the field are the major sources of biomass burning in China, accounting for nearly 90% of the total biomass burning on dry weight base. Field burning of crop residue estimated from satellite burned area is less than 1% of that estimated from ground survey data; because of this and because biofuel is burned indoor, the majority of biomass burning in China is not seeable from satellite. Statistical data showed that the occurrence of forest fire in China has decreased dramatically since the 1980s; however, the forest fire area detected by satellites in 2000 was 13 times that shown by statistics. Grassland fires are a minor source of biomass burning in China. We estimated carbon monoxide (CO) emission from open biomass burning (field burning of crop residue and forest and grassland fires) to be 16.5 Tg in 2000, with a 90% uncertainty range of 3.4–34 Tg. Uncertainties in CO emission factors, especially for field burning of crop residue, contributed much more to the variance than those in the activity data. This suggests the importance of narrowing the uncertainty range of emission factors.

Vertical profiles of springtime ozone (O3) over the Osaka metropolitan area in Japan were investigated by means of aircraft-based observations in March 2001 (Period I) and March 2003 (Period II). The observations in Period I were carried out during an episode of high O3 concentration under stagnant meteorological conditions, whereas in Period II, pollution levels were low and the weather was cloudy with strong winds. The elevated O3 concentration in the surface mixing layer in Period I was a result of local photochemical production as well as trans-boundary air pollution transported from East Asia. In contrast, the O3 concentration in Period II was very low, corresponding to the O3 level of ‘clean continental’ air masses from the northern Asian continent. On the basis of the vertical O3 profiles observed in Period I, we estimated the contributions of local photochemical production and trans-boundary air pollution to the O3 within the mixing layer, local photochemical production contributed −3% to 33% and trans-boundary air pollution contributed 8%–27%. We found that the trans-boundary air pollution made a notable contribution to the springtime O3 in the Osaka metropolitan area, its contribution being comparable to that of local photochemical production.

Ozone (O 3 ) concentrations in East Asia were simulated using the Community Multi-scale Air Quality model and their reproducibility was confirmed by comparing with observation data at Japanese monitoring sites. The model can reproduce the seasonal variation of surface O 3 over Japan. In particular, for the southern parts of Japan, simulated surface O 3 concentrations are strongly correlated with observations. Surface O 3 distribution over East Asia varies dynamically from season to season according to the meteorological condition. In May and June, 2-month average O 3 concentrations in the boundary layer are highest, 55–70 ppbv over East China and Japan at 35–40°N. We estimated the seasonal variation of the contribution of chemically produced O 3 by east Asian regional emissions. In the summertime, the contribution of the regional Asian emissions to O 3 concentrations is around 40–70% over most of China, and the highest is 60–70% ( 3 concentrations over East Asia are strongly influenced by the chemical production by regional emissions during summer season. However, the inflow from outside of this model domain also contributes substantial O 3 concentration over East Asia and its contribution is predominant in winter and early spring. The seasonal change of O 3 concentrations over Japan is characterized by two peaks in spring and autumn and summer minimum. The spring peak event in 2002 consists of split peaks: the first peak in Mar–Apr is mainly influenced by the inflow from outside of this model domain, the second spring peak between May and June is mainly influenced by chemically produced O 3 by regional emissions. During the summer season, O 3 concentrations are the lowest over year because of the weak Asian outflow and northward penetration of the marine air mass.

Ammonia, nitrous oxide, and methane emission from animal farming of South, Southeast, and East Asia, in 2000, was estimated at about 4.7 Tg NH3–N, 0.51 Tg N2O–N, and 29.9 Tg CH4, respectively, using the FAO database and countries’ statistic databases as activity data, and emission factors taking account of regional characteristics. Most of these atmospheric components, up to 60–80%, were produced in China and India. Pakistan, Bangladesh, and Indonesia, which were large source countries next to China and India, contributed more than a few percent of total emission ofeach atmospheric component. The largest emission livestock were cattle whose contribution was considerably high in South, Southeast, and East Asia; more than one-fourth of ammonia and nitrous oxide emissions: more than halfofmethane emission. The other major livestock for nitrous oxide and ammonia emissions were pigs. For methane emission, buffaloes were second source livestock. To provide spatial distributions of these gases, the emissions ofcounty and district level were allocated into each 0.5 1 grid by means ofthe weighting by high-resolution land cover datasets. The regions with considerable high emissions ofall components were able to be found at the Ganges delta and the Yellow River basin. The spatial distributions for ammonia and nitrous oxide emissions were similar but had a substantial difference from methane distribution. r 2004 Elsevier Ltd. All rights reserved.

No observed data have been found in the Fukushima Prefecture (FP) for the time-series of atmospheric radionuclides concentrations just after the Fukushima Daiichi Nuclear Power Plant (FD1NPP) accident. Accordingly, current estimates of internal radiation doses from inhalation, and atmospheric radionuclide concentrations by atmospheric transport models are highly uncertain. Here, we present a new method for retrieving the hourly atmospheric (137)Cs concentrations by measuring the radioactivity of suspended particulate matter (SPM) collected on filter tapes in SPM monitors which were operated even after the accident. This new dataset focused on the period of March 12-23, 2011 just after the accident, when massive radioactive materials were released from the FD1NPP to the atmosphere. Overall, 40 sites of the more than 400 sites in the air quality monitoring stations in eastern Japan were studied. For the first time, we show the spatio-temporal variation of atmospheric (137)Cs concentrations in the FP and the Tokyo Metropolitan Area (TMA) located more than 170 km southwest of the FD1NPP. The comprehensive dataset revealed how the polluted air masses were transported to the FP and TMA, and can be used to re-evaluate internal exposure, time-series radionuclides release rates, and atmospheric transport models.

In this study, the top-down NOx emissions estimated from satellite observations of NO2 vertical column densities over North Korea from 1996 to 2009 were analyzed. Also, a bottom-up NOx emission inventory from REAS 1.1 from 1980 to 2005 was analyzed with several statistics. REAS 1.1 was in good agreement with the top-down approach for both trend and amount. The characteristics of NOx emissions in North Korea were quite different from other developed countries including South Korea. In North Korea, emissions from industry sector was the highest followed by transportation sector in the 1980s. However, after 1990, the NOx emissions from other sector, mainly agriculture, became the 2nd highest. Also, no emission centers such as urban areas or industrial areas were distinctively observed. Finally, the monthly NOx emissions were high during the warm season.

The relationship between emission intensity of (nitrogen oxides) (NO x ), NC non-methane hydrocarbons (NMHC) and O 3 concentration covering the Kanto area (Tokyo and surrounding prefectures) were investigated based on data analysis and model simulation. The observed trend in NO x concentration increased and the NMHC/NO x ratio and NMHC concentration decreased from 1978 to 1990. These emission changes will act to change the place where the maximum ozone is observed in the Kanto area. The fact is that the location of the daily maximum oxidant concentration has moved further from the emission areas. To clarify the temporal and areal distribution of photochemical air pollution in the Kanto area, the Urban Airshed Model (UAM) was applied. Assuming 25% decrease in NMHC and 50% increase in NO x emission intensities, simulation result showed almost the same maximum O 3 value compared with the base-case simulation for 1981. On the other hand, the time when the maximum value appeared changed from 1400JST to 1600JST. Higher concentrations of oxidants were usually observed near the shore in the morning, and moved inland following sea breeze penetration. Under these meteorological conditions, the time shift obtained by the UAM simulation corresponds to the observed areal shift of the daily maximum O 3 concentration.

High concentrations of nitrogen dioxide are frequently observed in the Osaka area in the spring. To clarify the mechanism of springtime air pollution formation, a series of three-dimensional field observations was conducted in April 1993 covering Osaka and the surrounding area. During the aircraft observations of 19–21 April 1993, high concentrations of photochemical air pollution were observed over the Osaka area under a stagnant meteorological condition. The maximum observed ozone concentration was more than 150 ppb. The vertical distribution of ozone was uniform up to 2400 m in the daytime. At Mt. Ikoma (600 m), the ozone level was almost constant during the afternoons of 19–20 April 1993, ranging from 80 to 100 ppb, and the presence of aged secondary pollutants was detected in the nighttime. The upper ozone concentration above 3000 m was approximately 60 ppb. The observational results, near the surface and aloft, indicate the importance of photochemically produced ozone and transported backgr...

We are witnessing a crucial change in how we quantify and understand emissions of greenhouse gases and air pollutants, with an increasing demand for science-based transparent emissions information produced by robust community efforts. Today’s scientific capabilities, with near-real-time in-situ and remote sensing observations combined with forward and inverse models and a better understanding of the controlling processes, are contributing to this transformation and providing newapproaches to derive, verify, and forecast emissions (Tong et al., 2011; Frost et al., 2012) and to quantify their impacts on the environment (e.g., Bond et al., 2013). At the same time, the needs for emissions information and the demands for their accuracy and consistency have grown. Changing economies, demographics, agricultural practices, and energy sources, along with mandates to evaluate emissions mitigation efforts, demonstrate compliance with legislation, and verify treaties, are leading to new challenges in emissions understanding. To quote NOAA Senior Technical Scientist David Fahey, “We are in the Century of Accountability. Emissions information is critical not only for environmental science and decision-making, but also as an instrument of foreign policy and international diplomacy.” Emissions quantification represents a key step in explaining observed variability and trends in atmospheric composition and in attributing these observed changes to their causes. Accurate emissions data are necessary to identify feasible controls that reduce adverse impacts associated with air quality and climate and to track the success of implemented policies. To progress further, the international community must improve the understanding of drivers and contributing factors to emissions, and it must strengthen connections among and within different scientific disciplines that characterize our environment and entities that protect the environment and influence further emissions. The Global Emissions InitiAtive, GEIA (http://www.geiacenter. org/), is a center for emissions information exchange and competence building created in 1990 in response to the need for high quality global emissions data (Graedel et al., 1993). While the past two decades have seen considerable progress in developing, improving and assessing emission estimates, emissions continue to be a major contributor to overall uncertainty in atmospheric model simulations. Moving forward, GEIA aims to help build emissions knowledge in a rapidly evolving society by: 1) enhancing understanding, quantification, and analysis of emissions processes; 2) improving access to emissions information; and 3) strengthening the community of emissions groups involved in research, assessment, operations, regulation and policy.

Photochemical air pollution is still a serious environmental issue in Tokyo and Osaka areas. To clarify the past trend and present status of photochemical air pollution, the annual trends of daily maximum oxidant concentration covering Kanto (Tokyo and surrounding prefectures) and Kansai (Osaka and surrounding prefectures) areas were analyzed. Trends in the photochemical air pollution and NOx and VOC precursors showed identical characteristics both in Tokyo and Osaka areas. Trends in volatile organic hydrocarbons and NOx were analyzed; NOx is incresing and NMHC/NOx ratio is decreasing in the long term over both Kanto and Kansai areas, indicating an increase in ozone forming potential and a decrease in photochemical reactivity, which may be responsible for the air pollution patterns observed in the Tokyo and Osaka areas. The location of the daily maximum oxidant concentration has moved further from the emission areas.

The high concentration of NO2 in the Tokyo Metropolitan area was investigated by means of air quality monitoring station data analysis and two numerical models: a photochemical box model and a photochemical grid model. Based on monitoring data, the typical variation with time of NO, NO2 and O3 for days with high NO2 concentrations is presented. The application of the photochemical box and photochemical grid models successfully reproduced these variations when using typical emission intensities for NOx and NMHC from the Tokyo downtown area. Model results revealed that the high concentrations of NO2 in winter (exceeding the Japan environmental quality standard) mainly result from photochemical oxidation of NO to NO2.

We developed an exposure estimation model for an epidemiological study on the effect of traffic-related air pollutants on respiratory diseases. The model estimates annual average outdoor concentration of nitrogen oxides (NOx) and elemental carbon (EC). The model is composed of three nested plume dispersion type submodels treating different spatial scales from a few meters to tens of kilometers. The emissions from road traffic was estimated at high spatial resolution along the paths of roads taking into account the effects of individual building shape and traffic signals to secure accuracy near trunk roads where most of the subjects of the epidemiological study resided. Model performance was confirmed by field measurements at permanent local government stations and purpose-built temporary stations; the latter supplemented roadside monitoring points and provided EC concentrations, which are not measured routinely. We infer that EC emissions were underestimated by using the available database because there were significant contributions to EC concentrations from sources that did not emit much NOx. An adjustment concentration yielded good agreement between model estimates and field measurements.

The emission, concentration levels, and transboundary transport of particulate polycyclic aromatic hydrocarbons (PAHs) in Northeast Asia were investigated using particulate PAH measurements, the newly developed emission inventory (Regional Emission inventory in ASia for Persistent Organic Pollutants version, REAS-POP), and the chemical transport model (Regional Air Quality Model ver2 for POPs version, RAQM2-POP). The simulated concentrations of the nine particulate PAHs agreed well with the measured concentrations, and the results firmly established the efficacy of REAS/RAQM2-POP. It was found that the PAH concentrations in Beijing (China, source region), which were emitted predominantly from domestic coal, domestic biofuel, and other transformations of coal (including coke production), were approximately 2 orders of magnitude greater than those monitored at Noto (Japan, leeward region). In Noto, the PAH concentrations showed seasonal variations; the PAH concentrations were high from winter to spring due to contributions from domestic coal, domestic biofuel, and other transformations of coal, and low in summer. In summer, these contribution were decrease, instead, other sources, such as the on-road mobile source, were relatively increased compared with those in winter. These seasonal variations were due to seasonal variations in emissions from China, as well as transboundary transport across the Asian continent associated with meteorological conditions.

[1] We examine springtime ozone trends at nine remote locations in Japan during the last decade. The observed decadal ozone trends are relatively small at surface sites but are substantially larger at a mountainous site. We use a regional chemistry-transport model to explore the observed changes and how changes in Asian anthropogenic emissions have contributed to the observed increasing trends. The model with yearly-dependent regional emissions successfully reproduces the levels, variability, and interannual variations of ozone at all the surface sites. It predicts increasing trends at the mountainous site, suggesting that increasing Asian anthropogenic emissions account for about half the observed increase. However, the discrepancy between the observation and model results after 2003 (the time of largest emission increase) suggests significant underestimation of the actual growth of the Asian anthropogenic emissions and/or incompleteness in the modeling of pollution export from continental Asia.

Published on Web 11/16/2015 In the original version of TABLE 1, TABLE 2, and Appendix A in this article, there were some incorrect expressions. The corrected expressions are listed in the following table; Erratum to: A Database of Hourly Atmospheric Concentrations of Radiocesium (134Cs and 137Cs) in Suspended Particulate Matter Collected in March 2011 at 99 Air Pollution Monitoring Stations in Eastern Japan

Chiba prefecture is located in the eastern side of Tokyo Metropolitan Area(TMA), and it is adjacent to the city of Tokyo. In this area, air pollution is a serious environmental issue, which is caused by the pollutants emitted within and around the area. In order to prevent air pollution, a new Air Pollution Monitoring and Management System was introduced by the Chiba prefectural government in April, 1996. This system consists of real-time ambient air quality and source monitoring, data processing system and an air quality forecasting system. Almost 130 air monitoring stations transmit hourly air quality and wind data to the system center. Sixty-five major industries also transmit hourly emission intensity and related source data. The advanced air quality forecasting system can predict future ambient levels of photochemical oxidant(Ox) and nitrogen dioxide(NO2) up to 48-hours based on the predicted meteorological conditions. Photochemical air pollution warnings are issued when the hourly values of Ox exceed 120ppb and the adverse meteorological conditions are predicted to sustain these levels. When air pollution forecasting warning is issued based on the results obtained from the forecasting system, the emergency information are sent rapidly to the municipalities and to operating factories in order to mitigate the effects of high air pollution.

Several different inventories of global and regional anthropogenic and biomass burning emissions are assessed for the 1980-2010 period. The species considered in this study are carbon monoxide, nitrogen oxides, sulfur dioxide and black carbon. The inventories considered include the ACCMIP historical emissions developed in support of the simulations for the IPCC AR5 assessment. Emissions for 2005 and 2010 from the Representative Concentration Pathways (RCPs) are also included. Large discrepancies between the global and regional emissions are identified, which shows that there is still no consensus on the best estimates for surface emissions of atmospheric compounds. At the global scale, anthropogenic emissions of CO, NOx and SO2 show the best agreement for most years, although agreement does not necessarily mean that uncertainty is low. The agreement is low for BC emissions, particularly in the period prior to 2000. The best consensus is for NOx emissions for all periods and all regions, except for China, where emissions in 1980 and 1990 need to be better defined. Emissions of CO need better quantification in the USA and India for all periods; in Central Europe, the evolution of emissions during the past two decades needs to be better determined. The agreement between the different SO2 emissions datasets is rather good for the USA, but better quantification is needed elsewhere, particularly for Central Europe, India and China. The comparisons performed in this study show that the use of RCP8. 5 for the extension of the ACCMIP inventory beyond 2000 is reasonable, until more global or regional estimates become available. Concerning biomass burning emissions, most inventories agree within 50-80%, depending on the year and season. The large differences between biomass burning inventories are due to differences in the estimates of burned areas from the different available products, as well as in the amount of biomass burned. © 2011 Springer Science+Business Media B.V.