High resolution Air Quality simulation in the Himalayan valleys, a case study in Bhutan

Abstract. Increases in surface ozone (O3) and fine particulate matter (≤2.5 μm aerodynamic diameter, PM2.5) are associated with excess premature human mortalities. We estimate changes in surface O3 and PM2.5 from pre-industrial (1860) to present (2000) and the global present-day (2000) premature human mortalities associated with these changes. We extend previous work to differentiate the contribution of changes in three factors: emissions of short-lived air pollutants, climate change, and increased methane (CH4) concentrations, to air pollution levels and associated premature mortalities. We use a coupled chemistry-climate model in conjunction with global population distributions in 2000 to estimate exposure attributable to concentration changes since 1860 from each factor. Attributable mortalities are estimated using health impact functions of long-term relative risk estimates for O3 and PM2.5 from the epidemiology literature. We find global mean surface PM2.5 and health-relevant O3 (defined as the maximum 6-month mean of 1-h daily maximum O3 in a year) have increased by 8 ± 0.16 μg m−3 and 30 ± 0.16 ppbv (results reported as annual average ±standard deviation of 10-yr model simulations), respectively, over this industrial period as a result of combined changes in emissions of air pollutants (EMIS), climate (CLIM) and CH4 concentrations (TCH4). EMIS, CLIM and TCH4 cause global population-weighted average PM2.5 (O3) to change by +7.5 ± 0.19 μg m−3 (+25 ± 0.30 ppbv), +0.4 ± 0.17 μg m−3 (+0.5 ± 0.28 ppbv), and 0.04 ± 0.24 μg m−3 (+4.3 ± 0.33 ppbv), respectively. Total global changes in PM2.5 are associated with 1.5 (95% confidence interval, CI, 1.2–1.8) million cardiopulmonary mortalities and 95 (95% CI, 44–144) thousand lung cancer mortalities annually and changes in O3 are associated with 375 (95% CI, 129–592) thousand respiratory mortalities annually. Most air pollution mortality is driven by changes in emissions of short-lived air pollutants and their precursors (95% and 85% of mortalities from PM2.5 and O3 respectively). However, changing climate and increasing CH4 concentrations also contribute to premature mortality associated with air pollution globally (by up to 5% and 15%, respectively). In some regions, the contribution of climate change and increased CH4 together are responsible for more than 20% of the respiratory mortality associated with O3 exposure. We find the interaction between climate change and atmospheric chemistry has influenced atmospheric composition and human mortality associated with industrial air pollution. Our study highlights the benefits to air quality and human health of CH4 mitigation as a component of future air pollution control policy.

Urban residential energy switching in China between 1980 and 2014 prevents 2.2 million premature deaths

Black CarbonThe Dark Horse of Climate Change Drivers F or decades, efforts to slow global warming have mostly aimed to limit heat-trapping emissions of carbon dioxide (CO 2 ).Now scientists are pointing to a different class of warming agents they say also must be targeted to keep global temperatures in check.Dubbed "shortlived climate forcings" (SLCFs), these other emissionsnamely, black carbon particles, methane, hydrofluorocarbons, and tropospheric ozone-are even more powerful than CO 2 in terms of their warming potential.But they persist in the atmosphere for much shorter durations than CO 2 , which can linger airborne for hundreds to thousands of years. 1 Steve Seidel, vice president for policy analysis at the Pew Center on Global Climate Change, says the recent emphasis on SLCFs represents new policy thinking on climate change."We thought the Kyoto Protocol and its follow-on agreements would get us to where we need to be, but that's not working out the way we hoped it would," he says."So, we're broadening the discussion and opening up new pathways for going forward."More than three-quarters of the world's black carbon is thought to come from developing countries, discharged from cookstoves, open burning, and older diesel engines.This data visualization uses data from NASA's GEOS-5 Goddard Chemistry Aerosol and Transport (GOCART) climate model to show atmospheric concentrations of black carbon on 26 September 2009.Aerosol optical thickness ranges nonlinearly from 0.002 (transparent) to 0.02 (purple) to 0.2 (white).Animations of global black soot transport are available at

Source attribution of black carbon affecting regional air quality, premature mortality and glacial deposition in 2000

iiTSE

BackgroundAir pollution in China has raised great concerns due to its adverse effects on air quality, human health, and climate. Emissions of air pollutants (APs) are inherently linked with CO2 emissions through fossil-energy consumption. Knowledge of the characteristics of APs and CO2 emissions and their relationships is fundamentally important in the pursuit of co-benefits in addressing air quality and climate issues in China. However, the linkages and interactions between APs and CO2 in China are not well understood.ResultsHere, we conducted an ensemble study of six bottom-up inventories to identify the underlying drivers of APs and CO2 emissions growth and to explore their linkages in China. The results showed that, during 1980–2015, the power and industry sectors contributed 61–79% to China’s overall emissions of CO2, NOx, and SO2. In addition, the residential and industrial sectors were large emitters (77–85%) of PM10, PM2.5, CO, BC, and OC. The emissions of CH4, N2O and NH3 were dominated by the agriculture sector (46–82%) during 1980–2015, while the share of CH4 emissions in the energy sector increased since 2010. During 1980–2015, APs and greenhouse gases (GHGs) emissions from residential sources generally decreased over time, while the transportation sector increased its impact on recent emissions, particularly for NOx and NMVOC. Since implementation of stringent pollution control measures and accompanying technological improvements in 2013, China has effectively limited pollution emissions (e.g., growth rates of –10% per year for PM and –20% for SO2) and slowed down the increasing trend of carbon emissions from the power and industrial sectors. We also found that areas with high emissions of CO, NOx, NMVOC, and SO2 also emitted large amounts of CO2, which demonstrates the possible common sources of APs and GHGs. Moreover, we found significant correlations between CO2 and APs (e.g., NOx, CO, SO2, and PM) emissions in the top 5% high-emitting grid cells, with more than 60% common grid cells during 2010–2015.ConclusionsWe found significant correlation in spatial and temporal aspects for CO2, and NOx, CO, SO2, and PM emissions in China. We targeted sectorial and spatial APs and GHGs emission hot-spots, which help for management and policy-making of collaborative reductions of them. This comprehensive analysis over 6 datasets improves our understanding of APs and GHGs emissions in China during the period of rapid industrialization from 1980 to 2015. This study helps elucidate the linkages between APs and CO2 from an integrated perspective, and provides insights for future synergistic emissions reduction.

In Brazil, increasing air pollution in urban areas has led to a rise in respiratory diseases among children and the elderly and has also been the main cause of hospital admissions. This study aims to evaluate the air pollution levels in Vitória, capital of Espírito Santo State, Brazil, in comparison to Brazilian legislation and recent World Health Organization (WHO) guidelines, analyzing the spatial distribution of asthma cases treated at local outpatient services. A descriptive epidemiological study was performed with daily records on air pollution and outpatient treatment for respiratory diseases from 2001 to 2003, for children under 6 years of age. A geographic information system (GIS) was used to identify asthma distribution in the municipality. Air pollution levels were relatively low when compared to the Brazilian legislation and WHO guidelines. Only mean PM10 and NO2 exceeded the annual quality standard. The three highest asthma outpatient treatment rates were observed in the districts of São José, Jabou, and Morro do Quadro.

New scientific understanding could increase the cost-effectiveness of local and regional air quality management policies, enhance the acceptance of mitigation measures for long-lived greenhouse gas (GHG) emissions, and reveal win-win portfolios of controls for short-lived substances that yield immediate health and crop benefits while limiting temperature increase in the near term. However, although substantial efforts have been devoted to global analyses of the emissions of carbon dioxide (CO2) and other long-lived GHGs, air pollutant emissions have received only limited attention in the global context. Past and likely future trends in air pollutant emissions evolve rather differently from those of long-lived GHGs, so that superficial extrapolations of GHG trends would lead to misleading conclusions. In many world regions, the evolution of air pollutant emissions has effectively decoupled from economic growth. Since 1990, air pollutant emissions declined (sulfur dioxide, SO2), stabilized (nitrogen oxides, NOx), or increased slightly (black carbon, BC; organic carbon, OC; and ammonia, NH3). This review discusses to what extent structural changes, technological improvements, and dedicated environmental legislation have contributed to these changes. The scenarios of future emissions in the literature span a wide range, mainly owing to different assumptions about future environmental policies. Although the more recent scenarios agree on declining air pollutants up to 2030, avoiding potential rebounds of emissions after 2030 will require additional policy interventions.

Identifies household air pollution (HAP) as a major health risk, especially in poor countries which rely on biomass for cooking. Particulate matter concentration in indoor kitchens that use solid fuels for cooking account for an estimated 370,000 premature deaths globally based on 2014 data. Direct health impacts include chronic obstructive pulmonary disease, lung disease, and cataracts while children face acute lower respiratory infections. Interventions offer cleaner stoves through national stove programs and the development of standards and guidelines to promote only the cleanest devices, emphasizing the optimal use of electricity, natural gas, or LPG. Little benefit comes from converting individual users, so interventions need to target communities to become “smokeless” villages. Successful stove programs typically involve a public subsidy for the poor and because of savings on health care costs, its expense can be justified. Full adoption of a newer technology for clean cooking may not occur until generational change, with the present generation continuing to use the traditional methods despite the benefits to the family of the cleaner technology.

The urban transport sector is one of most significant contributors to greenhouse gas (GHG) and air pollutant (AP) emissions. To achieve co-benefits of GHG and AP emission reductions, a synergistic mitigation approach targeting both climate change and air pollution has gained more attention. In this study, we evaluate mitigation synergy and policy implications for GHGs and nine APs, namely, sulfur dioxide (SO2), nitrogen oxides (NO x ), carbon monoxide (CO), particulate matters (PM10 and PM2.5), black carbon (BC), organic carbon (OC), volatile organic compounds (VOCs) and ammonia (NH3), in the transport sector of Xiamen, China, during the 2013–2060 period using the Low Emissions Analysis Platform model and quantitative analysis methods. Results show that light-duty vehicles, river boats, buses and heavy-duty trucks are significant common sources of GHG and AP emissions. Road sector abatement during 2013–2020 was most prominent, especially for CO, NO X , VOCs and GHGs. In this sector, guide green travel (GGT) and adjust energy structure (AES) are dominant measures for mitigation synergy between GHGs and APs. From 2021 to 2060, emission pathways for GHGs, SO2, CO, VOCs and NH3 under optimize transport structure (OTS), AES and GGT scenarios will decrease markedly. Their emissions will peak soon relative to those under business as usual scenario. Additionally, the potential of mitigation synergy may mainly be attributed to the road and shipping sectors under AES scenario, which is the most effective in reducing PM10, PM2.5, BC and OC emissions; the mitigation potential under the AES scenario for GHGs and other APs is nearly 1–4 times as high as that under OTS and GGT scenarios. Therefore, mitigation synergy, especially in adjusting the energy structure for the transport sector, is essential for achieving the simultaneous goals of the ‘blue sky’ and ‘carbon peaking and neutrality’.

Development of current and future pollutant emissions for Portugal

After almost three decades of intensive research on acidic deposition, it is still an important environmental issue in Europe '- and North America. Furthermore, anthropogenic emissions of the major pollutants involved _ sulfur dioxide (S02) and nitrogen oxides (NO) __ are increasing rapidly as industrialization proceeds and the use of fossil fuels increases in new geographical areas, including parts of eastern and southern Asia, southern Africa, and South America. These pollutants and their transformation products have long atmospheric lifetimes and can be carried by weather systems to distances of up to a few thousand kilometers from their point of emission. This causes acid deposition far from the primary source of pollution, thus making it a regional problem and an international transboundary issue. Considerable advances in the understanding of acidic emissions, transportation, deposition and consequent effects on ecosystems have allowed the development of the concept of “Critical loads, which has become an integral part of international negotiations aimed at controlling emission levels within Europe. Abatement strategies based on the critical load concept resulted in substantial decreases of acidic emissions, which have led to a lower degree of environmental degradation and even recovery in deposition. Some ecosystems in eastern Asia, where a regional acid monitoring network [El-WET) is some ecosystems in eastern Asia, a regional acid already established implementation of some abatement strategies is under consideration. Economic progress in the Caspian region is associated with an increase in the oil and gas production, industrialization and a higher demand for energy and food production. On the basis of previous experiences, such a progress will definitely lead to a considerable increase in emissions of acidifying pollutants. It is important that the environmental impacts of these emissions are estimated and taken into account in the planning process. The impact study is especially very crucial for the highly sensitive ecosystem of the southern Caspian watershed. If less polluting techniques are applied in the region, environmental problems, like those experienced in Europe and North America may be lessened. A rational strategy for limiting the adverse effects of acidifying pollutants should include consideration of critical loads and critical levels. So far, only preliminary estimates of critical loads are available for some parts of the regionand there is a real need for regionalresearch programs in this regard. Experience from policy actions, especially in the European region, could also be very useful for the Caspian states. There is, indeed, an obligation for environmental scientists to promote communication and cooperation with policymaking and decision-making sectors of the Caspian societies hoping that they can have better, if not the best, policy options to prevent further environmen-tal deterioration. References Battarbee, R.W. et al. 1985.Lake acidification in Galloway: A palaeoecologicai test of competing hypotheses. Nature, 314: 350. Brodin, Y. and Kuylenstiema, J 1992. Acidification and critical loads in Nordic countries: A background. Ambic, 2 1, No. 5:332. Cerny, l and Paces, T. (eds) 1995. Acidification in the Black Triangle Region. C.G.S, Prague. Charles, D.F. 1991. Effects of acidic deposition on North American lakes: Palaeolimnological evidence from diatoms and chryophtes. Phil- Trans. R. Soc. London, B327: 403. Cowling, E.B. 1982. A historical resume of progress in scientific and public understanding of acid precipitation and its consequences. Environ. Soi.'l'ech., 16: 1 10A. Elvingson, P. 1996. Evidence of continued decline. Acid News, 5: 6. Erisman, J.W. et al. 1994a. A generalized description of the deposition acidifying pollutants on a small scale in Europe. in: Borrei et al. (eds.), The proc. of EUROTRC symp.'94. Academic, 588p. Galloway, J.N. 1995. Acid deposition: Perspectives in time and space. Water, Air, and Soil Pollution, 85: 15. Galloway, J.N. 2001. Acidification of the World: Natural and Anthropogenic. Water, Air, and Soil pollution, 130: 17. Havas, M. and Rosseland, B.0. 1995. Response of zooplankton, benthos and fish to acidification: An overview. water, Airand Soil Pollution, 85: 5 1. i-lenrikson, A. et al. 1992. Critical loads of acidity: Nordic surface waters. Ambio, 21: 356. Hultberg, H and Grennfelt. P. 1991. Sulphur and sea salt deposition as reflected by throughfall and runoff chemistry in forested catchments. lVL, Bl009, Swedish Environ mental Research institute, Goteborg, Sweden. Lovblad, G. et al. 1992. Deposition of sulfur and nitrogen in the Nordic countries: Present and future Ambio, 2 1, No. 5: 339. Matzner, E. and Murach, D. 1995. Soil changes induced by air pollutant deposition and their implication for forests in Central Europe. Water, Air and Soil Pollution, 85: 63. Oden, S. 1968.The acidification of air and precipitation and its consequences in the natural environment Ecological Committee Bulletin 1, Swedish Natural Science Research Council, Stockholm. Translations Consultants, Ltd. Arlington, USA. Renberg, I. et al. 1991. Recent acidification and biological changes in Lilla Oresjon, southwest Sweden, and the relation to atmospheric pollution and land-use history. Phil, Trans. R. Soc. London, B327: 391. RGAR 1997. Acid deposition in die United Kingdom, 1992-1994. Fourth report of the Review Group on Acid Ram, Department on Environment. Rodhe, H. et al. 1995. Acid Rain 95? Summary Statement from the 5th International conference On Acidic- Deposition Science and Policy. Gothenburg, Sweden, 26 . -30 June 1995: Kluwer Academic. Satake, K. et al. 2001. Acid Rain 2000 — Conference Summary Statement —Looking Back to the past and Thinking of the Future. Water, Air, and Soil Pollution,_130: 1. Streets, D.G. and Waldhoff, S.T. 2000: Present and future emissions of air pollutants in China: S02, No, and CO. Atmospheric Environment, 34: 363. UN ECE 1988. Conclusions and draft recommendations of the workshops on critical levels for forests, crops and materials and on critical loads for sulfur and nitrogen, EB. AlRIR 30, Geneva. UN ECE 1997. Forest condition in Europe. Results of the 1996 crown condition survey, 1997 Technical Report. Brussels, Belgium.

Abstract. Modern-Era Retrospective analysis for Research and Applications v.2 (MERRA-2), Copernicus Atmosphere Monitoring Service Operational Analysis (CAMS-OA), and a high-resolution regional Weather Research and Forecasting model coupled with chemistry (WRF-Chem) were used to evaluate natural and anthropogenic particulate matter (PM) air pollution in the Middle East (ME) during 2015–2016. Two Moderate Resolution Imaging Spectrometer (MODIS) retrievals – combined product Deep Blue and Deep Target (MODIS-DB&DT) and Multi-Angle Implementation of Atmospheric Correction (MAIAC) – and Aerosol Robotic Network (AERONET) aerosol optical depth (AOD) observations as well as in situ PM measurements for 2016 were used for validation of the WRF-Chem output and both assimilation products. MERRA-2 and CAMS-OA assimilate AOD observations. WRF-Chem is a free-running model, but dust emission in WRF-Chem is tuned to fit AOD and aerosol volume size distributions obtained from AERONET. MERRA-2 was used to construct WRF-Chem initial and boundary conditions both for meteorology and chemical and aerosol species. SO2 emissions in WRF-Chem are based on the novel OMI-HTAP SO2 emission dataset. The correlation with the AERONET AOD is highest for MERRA-2 (0.72–0.91), MAIAC (0.63–0.96), and CAMS-OA (0.65–0.87), followed by MODIS-DB&DT (0.56–0.84) and WRF-Chem (0.43–0.85). However, CAMS-OA has a relatively high positive mean bias with respect to AERONET AOD. The spatial distributions of seasonally averaged AODs from WRF-Chem, assimilation products, and MAIAC are well correlated with MODIS-DB&DT AOD product. MAIAC has the highest correlation (R=0.8), followed by MERRA-2 (R=0.66), CAMS-OA (R=0.65), and WRF-Chem (R=0.61). WRF-Chem, MERRA-2, and MAIAC underestimate and CAMS-OA overestimates MODIS-DB&DT AOD. The simulated and observed PM concentrations might differ by a factor of 2 because it is more challenging for the model and the assimilation products to reproduce PM concentration measured within the city. Although aerosol fields in WRF-Chem and assimilation products are entirely consistent, WRF-Chem is preferable for analysis of regional air quality over the ME due to its higher spatial resolution and better SO2 emissions. The WRF-Chem’s PM background concentrations exceed the World Health Organization (WHO) guidelines over the entire ME. Mineral dust is the major contributor to PM (≈75 %–95 %) compared to other aerosol types. Near and downwind from the SO2 emission sources, nondust aerosols (primarily sulfate) contribute up to 30 % to PM2.5. The contribution of sea salt to PM in coastal regions can reach 5 %. The contributions of organic matter, black carbon and organic carbon to PM over the Middle East are insignificant. In the major cities over the Arabian Peninsula, the 90th percentile of PM10 and PM2.5 (particles with diameters less than 10 and 2.5 µm, respectively) daily mean surface concentrations exceed the corresponding Kingdom of Saudi Arabia air quality limits. The contribution of the nondust component to PM2.5 is <25 %, which limits the emission control effect on air quality. The mitigation of the dust effect on air quality requires the development of environment-based approaches like growing tree belts around the cities and enhancing in-city vegetation cover. The WRF-Chem configuration presented in this study could be a prototype of a future air quality forecast system that warns the population against air pollution hazards.

Geographical environment and climate change are basic factors for spatial fluctuations in the global distribution of air pollutants. Against the background of global climate change, further investigation is needed on how meteorological characteristics and complex geographical environment variations can drive spatial air pollution variations. This study analyzed the response of air pollutant emissions to climate change and the potential effects of air pollutant emissions on human health by integrating the air pollutant emission simulation model (GAINS) with 3 versions and CMIP5. The mechanism by which meteorological characteristics and geographical matrices can drive air pollution based on monitoring data at the site-scale was also examined. We found the total global emission of major air pollutants increased 1.32 times during 1970–2010. Air pollutant emissions will increase 2.89% and 4.11% in China and developed countries when the scenario of only maximum technically feasible reductions is performed (V4a) during 2020–2050. However, it will decrease 19.33% and 6.78% respectively by taking the V5a climate scenario into consideration, and precipitation variation will contribute more to such change, especially in China. Locally, the air circulation mode that is dominated by local geographical matrices and meteorological characteristics jointly affect the dilution and diffusion of air pollutants. Therefore, natural conditions, such as climate changes, meteorological characteristics and topography, play an important role in spatial air pollutant emissions and fluctuations, and must be given more attention in the processes of air pollution control policy making.

Human exposures to air pollution can vary sharply in space and time. Carefully designed mobile sampling campaigns are now able to reveal patterns of long-term ambient air pollution concentrations at fine scales (<< 100 m). Here, we report on a campaign where two specially equipped Google Street View cars mapped spatial patterns of air quality in the San Francisco Bay Area between May 2015 and December 2017. Cars were outfitted with reference-grade instruments to measure NO, NO2, black carbon (BC) and ultrafine particle number count at ~ 1 Hz. During a 30-month campaign, measurements occured on most weekdays during daytime hours, resulting in a large dataset: ~10M samples collected during > 4000 h, encompassing 100k km of driving. First, we sampled every road 20-50× within three neighborhoods (~30 km2) in Oakland, CA, during the first year of measurements. We found persistent fine-scale variability in pollution exists within many neighborhoods. In some neighborhoods, prominent ~50-200 m sized hotspots of elevated primary pollutants were ubiquitous, with pollutant levels varying by 5-8× within many city blocks. Next, during 1.5 years of follow-up measurements, we mapped pollutant concentrations in rural, suburban, and dense urban neighborhoods throughout the SF Bay Area. These measurements reveal how within-neighborhood pollution structure is overlaid on top of regional spatial gradients in air quality. Repeated measurements over the 2.5-year period demonstrate persistent spatial variability over time. Patterns of NO, NO2 and BC in Oakland had high correlation (r2 > 0.85) between the first and second years of measurement. Short-term measurement periods (~1-2 months) were sufficient to reproduce overall spatial patterns, albeit with ±30% bias in mean concentrations relative to annual-average conditions. This presentation summarizes how routine mobile air pollution monitoring reveals new information about spatial variability in population exposure to air pollution.