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This paper estimates a global CO2 emissions model using satellite data at 25 km resolution. The model incorporates industrial sources (including power, steel, cement, and refineries), fires, and non-industrial population-related factors associated with household incomes and energy requirements. It also tests the impact of subways in the 192 cities where they operate. We find highly significant effects with the expected signs for all model variables, including subways. In a counterfactual exercise estimating CO2 emissions with and without subways, we find they have reduced population-related CO2 emissions by about 50 % for the 192 cities and about 11 % globally. Extending the analysis to future subways for other cities, we estimate the magnitude and social value of CO2 emissions reductions with conservative assumptions about population and income growth and a range of values for the social cost of carbon and investment costs. Even under pessimistic assumptions for these costs, we find that hundreds of cities realize a significant climate co-benefit, along with benefits from reduced traffic congestion and local air pollution, which have traditionally motivated subway construction. Under more moderate assumptions, we find that, on climate grounds alone, hundreds of cities realize high enough social rates of return to warrant subway construction.

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Plastic waste, with an estimated lifetime of centuries, accounts for the major share of marine litter. Each year, thousands of fish, sea birds, sea turtles, and other marine species are killed by ingesting or becoming entangled with plastic debris. Reducing marine plastic pollution is particularly challenging for developing countries owing to the wide dispersal of plastic waste disposal and scarce public cleanup resources. To costeffectively reduce marine pollution, resources should target "hotspot" areas, where large volumes of plastic litter have a high likelihood of ending up in the ocean. Using new public information, this study develops a hotspot targeting strategy for Accra and Lagos, which are major sources of marine plastic pollution in West Africa. The same global information sources can support hotspot analyses for many other coastal cities that generate marine plastic waste. The methodology combines georeferenced household survey data on plastic use, measures of seasonal variation in marine plastic pollution from satellite imagery, and a model of plastic waste transport to the ocean that uses information on topography, seasonal rainfall, drainage to rivers, and river transport to the ocean. For cleanup, the results for West Africa assign the highest locational priority to areas with heavy plastic-waste disposal along river channels or in steeply sloped locations with high rainfall runoff potential near rivers. They assign the highest temporal priority to just before the onset of the first-semester rainy season, when runoff from the first rains transports large volumes of plastic waste that have accumulated during the dry season.

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Using new satellite data from the European Space Agency's Sentinel-5P system, this article investigates the spatial and temporal dynamics of vehicular traffic congestion, air pollution, and the distributional impacts on vulnerable populations in Dar es Salaam, Tanzania. The metro region's rapid growth in vehicle traffic exceeds road network capacity, generating congestion, transport delays, and air pollution from excess fuel use. Dangerously high pollution levels from tailpipe emissions put the health of vulnerable residents at risk, calling for the need to adopt continuous air-quality monitoring and effective pollution control. Our results highlight significant impacts of seasonal weather and wind-speed factors on the spatial distribution and intensity of air pollution from vehicle emissions, which vary widely by area. In seasons when weather factors maximize pollution, the worst exposure occurs along the wind path of high-traffic roadways. The study identifies priority areas for reducing congestion to yield the greatest exposure reduction for young children and the elderly in poor households. This new research direction, based only on the use of free global information sources with the same coverage for all cities, offers metropolitan areas in developing regions the opportunity to benefit from the rigorous analyses traditionally limited to well-endowed cites in developing countries.

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This paper explores the sources of spatial variation in child wasting and maternal anemia in three Indian states and six Bangladeshi divisions.  Our initial probability models incorporate traditionally-cited variables from Demographic and Health Surveys such as mother's education, mother's age and household wealth, along with seasonal fluctuations and regional fixed effects. The regional fixed effects are highly significant, even after controlling for the traditionally-cited determinants.  We then re-estimate our models, replacing regional fixed effects with measures of four factors that exhibit spatial clustering in the study area: provision of health services, political instability, religious culture, and flood-proneness.  Our re-estimated models show highly significant effects for all four factors, thereby highlighting potential gains from more effective policy interventions at the regional level.  Mothers and children whose socioeconomic status is identical have much better health outcomes in areas where health services are relatively plentiful, political stability prevails, key protein sources are more plentiful, and water is abundant.  Our results also demonstrate a strong association of mother's health status post-partum with long term health outcomes for children.

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Mangroves are an important ecosystem-based protection against cyclonic storm surge. As the surge moves through the mangrove forest, the tree roots, trunks, and leaves obstruct the flow of water. Damage to adjacent coastal lands is attenuated mainly by reducing (i) surge height, which determines the area and depth of inundation and (ii) water flow velocity. But the extent of mangrove protection depends on the density of tree plantings and the diameter of trunks and roots, along with an array of other forest characteristics (e.g., floor shape, bathymetry, spectral features of waves, and tidal stage at which waves enter the forest). Making efficient use of mangroves' protective capacity has been hindered by a lack of location-specific information. This study helps to fill that gap by estimating reduction in storm surge height and water flow velocity from mangroves at selected sites in cyclone-prone, coastal Bangladesh. A hydrodynamic model for the Bay of Bengal, based on the MIKE21FM system, was run multiple times to simulate the surge of cyclone Sidr (2007) at the Barisal coast. Estimates of surge height and water flow velocity were recorded first without mangroves and then with mangroves of various forest widths and planting densities, including specific information on local topography, bathymetry, and Manning's coefficients estimated from species' root and trunk systems. The results show a significant reduction in water flow velocity (29-92%) and a modest reduction in surge height (4-16.5 cm). These findings suggest that healthy mangroves can contribute to significant savings in rehabilitation and maintenance costs by protecting embankments from breaching, toe-erosion, and other damage.

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This paper investigates the possible impacts of climate change on aquatic salinity and mangrove species in the Bangladesh Sundarbans. The impact analysis combines the salinity tolerance ranges of predominant mangrove species with aquatic salinity measures in 27 scenarios of climate change by 2050. The estimates indicate significant overall losses for Heritiera fomes; substantial gains for Excoecaria agallocha; modest changes for Avicennia alba, A. marina, A. officinalis, Ceriops decandra, and Sonneratia apetala; and mixed results for species combinations. Changes in mangrove stocks are likely to change the prospects for forest-based livelihoods. The implications for neighboring communities are assessed by computing changes in high-value mangrove species for the five sub-districts in the Sundarbans. The results of the impact analysis indicate highly varied patterns of gain and loss across the five sub-districts. Overall, however, the results suggest that salinity-induced mangrove migration will have a strongly regressive impact on the value of timber stocks because of the loss of highest value timber species, Heritiera fomes. In addition, the augmented potential for honey production will likely increase conflicts between humans and wildlife in the region.

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Adaptation to climate change includes addressing sea-level rise (SLR) and increased storm surges in many coastal areas. Mangroves can substantially reduce vulnerability of the adjacent coastal land from inundation but SLR poses a threat to the future of mangroves. This paper quantifies coastal protection services of mangroves for 42 developing countries in the current climate, and a future climate change scenario with a 1-m SLR and 10  % intensification of storms. Findings demonstrate that while SLR and increased storm intensity would increase storm surge areas, the greatest impact is from the expected loss of mangroves. Under current climate and mangrove coverage, 3.5 million people and GDP worth roughly US $400 million are at risk. In the future climate change scenario, vulnerable population and GDP at risk would increase by 103 and 233  %. The greatest risk is in East Asia, especially in Indonesia and the Philippines as well as Myanmar.

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This paper estimates location-specific soil salinity in coastal Bangladesh for 2050. The analysis was conducted in two stages: First, changes in soil salinity for the period 2001-2009 were assessed using information recorded at 41 soil monitoring stations by the Soil Research Development Institute. Using these data, a spatial econometric model was estimated linking soil salinity with the salinity of nearby rivers, land elevation, temperature, and rainfall. Second, future soil salinity for 69 coastal sub-districts was projected from climate-induced changes in river salinity and projections of rainfall and temperature based on time trends for 20 Bangladesh Meteorological Department weather stations in the coastal region. The findings indicate that climate change poses a major soil salinization risk in coastal Bangladesh. Across 41 monitoring stations, the annual median projected change in soil salinity is 39 % by 2050. Above the median, 25 % of all stations have projected changes of 51 % or higher.

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This paper seeks to quantify the impact of a1-m sea-level rise on coastal wetlands in 86 developing countries and territories. It is found that approximately 68 % of coastal wetlands in these countries are at risk. A large percentage of this estimated loss is found in Europe and Central Asia, East Asia, and the Pacific, as well as in the Middle East and North Africa. A small number of countries will be severely affected. China and Vietnam(in East Asia and the Pacific), Libya and Egypt (in the Middle East and North Africa), and Romania and Ukraine (in Europe and Central Asia) will bear most losses. In economic terms, the loss of coastal wetlands is likely to exceed $703 million per year in 2000 US dollars.

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Obsolete pesticides have accumulated in almost every developing country or economy in transition over the past several decades. Concerned about the risks these chemicals pose to nearby residents, public health and environmental authorities are eager to reduce health threats by removing and decontaminating stockpile sites. However, there are many sites, cleanup can be costly, and public resources are scarce, so decision makers need to set priorities. Under these conditions, it seems sensible to develop a methodology for prioritizing sites and treating them sequentially, as budgetary resources permit. This paper presents a new methodology that develops a cleanup priority index for 1915 metric tons of obsolete pesticide formulations at 197 stockpile sites in Tunisia. The approach integrates information on populations at risk, their proximity to stockpiles, and the relative toxic hazards of the stockpiles. What emerges from the Tunisia results is a strategy for sequentially addressing all 197 sites to rapidly reduce potential health damage in a cost-effective way.

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With the development of new approaches to transplantation therapy, such as those building upon the potential found in stem cells, it is vital to pursue a clear understanding of transplantation risks. Allogeneic transplantation presents risk for the transmission of disease of various types, including genetic disease. Predisposition to develop cancer is a feature of numerous genetic disorders, and it may be transmissible by transplantation. Some genetic disorders predisposing to cancer are remarkably common, either worldwide or in specific populations, and they could pose significant risk. Hence, to reduce risk to recipients, there is reason to exclude from donation those potential donors (including embryos) harboring certain germ-line mutations. However, the frequent absence of readily identifiable features might confound the effort to exclude those who harbor mutation. Thus, it is also important to consider the magnitude of risk that they represent. For some disorders, life-threatening cancer is highly likely to develop in those individuals born with germ-line mutation, but whether recipients would face the same risk from transplanted mutation is not always evident. Given the diversity of pathways that lead to cancer, there may be diverse factors that impact the likelihood for cancer to develop in the recipient, with some factors decreasing and others increasing the risk. One factor of special concern is the possibility that manipulation of donor cells, prior to transplantation, might introduce additional genetic or epigenetic abnormality, thereby increasing the risk.

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Information on the health impacts of pesticides is quite limited in many developing countries, with many surveys relying solely on farmer self-assessments of their health status. To test the reliability of self-reported data, an acetyl cholinesterase enzyme (AChE) blood test was conducted for 190 rice farmers in the Mekong Delta, Vietnam. Results reveal a high prevalence of pesticide poisoning by organophosphate and carbamate exposure, where over 35% of test subjects experienced acute pesticide poisoning (a reduction of AChE >25%), and 21% chronically poisoned (>66% AChE reduction). Using the medical test results as benchmarks, we find that farmers' self-reported symptoms have very weak associations with actual poisoning. To investigate the possible determinants of pesticide poisoning, a probit model was constructed with pesticide amount, toxicity, training, and the use of protective measures as explanatory variables. The results indicate that although the absolute amount of pesticides used does not increase the probability of poisoning, a 1% increase in the use of highly hazardous pesticides (WHO Ia or Ib) increases the probability of poisoning by 3.9% and an increased use of protective measures decreases the probability of poisoning by 44.3%. We also find significant provincial differences in poisoning incidence after we control for individual factors. The provincial effects highlight the potential importance of negative externalities, and suggest that future research on pesticide-related damage should include information on local water, air and soil contamination.

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In this paper, we investigate individuals' exposure to indoor air pollution. Using new survey data from Bangladesh, average hours spent by members of households in the cooking area, living area and outdoors in a typical day are combined with the estimates of pollution concentration in different locations in order to estimate exposure. We analyse exposure at two levels: differences within households attributable to family roles, and differences across households attributable to income and education. Within households, we relate individuals' exposure to pollution in different locations during their daily round of activities. We find high levels of exposure for children and adolescents of both sexes, with particularly serious exposure for children under 5 years. Among prime-age adults, we find that men have half the exposure of women (whose exposure is similar to that of children and adolescents). We also find that elderly men have significantly lower exposure than elderly women. Across households, we draw on results from a previous paper, which relate pollution variation across households to choices of cooking fuel, cooking locations, construction materials and ventilation practices. We find that these choices are significantly affected by family income and adult education levels (particularly for women). Overall, we find that the poorest, least-educated households have twice the pollution levels of relatively high-income households with highly educated adults. Our findings further suggest that young children and poorly educated women in poor households face pollution exposures that are four times those for men in higher income households organized by more highly educated women. Since infants and young children suffer the worst mortality and morbidity from indoor air pollution, in this paper we consider measures for reducing their exposure. Our recommendations for reducing the exposure of infants and young children are based on a few simple, robust findings. Hourly pollution levels in cooking and living areas are quite similar because cooking smoke diffuses rapidly and nearly completely into living areas. However, outdoor pollution is far lower. At present, young children are only outside for an average of 3 hours per day. For children in a typical household, pollution exposure can be halved by adopting two simple measures: increasing their outdoor time from 3 to 5 or 6 hours per day, and concentrating outdoor time during peak cooking periods.

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