Childhood cancers and atmospheric carcinogens.
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STUDY OBJECTIVES: To retest previous findings that childhood cancers are probably initiated by prenatal exposures to combustion process gases and to volatile organic compounds (VOCs); and to identify specific chemical hazards. DESIGN: Birth and death addresses of fatal child cancers in Great Britain between 1966 and 1980, were linked with high local atmospheric emissions of different chemical species. Among migrant children, distances from each address to the nearest emissions "hotspot" were compared. Excesses of outward over inward migrations show an increased prenatal or early infancy risk. SETTING AND SUBJECTS: Maps of emissions of many different substances were published on the internet by the National Atmospheric Emissions Inventory and "hotspots" for 2001 were translated to map coordinates. Child cancer addresses were extracted from an earlier inquiry into the carcinogenic effects of obstetric radiographs; and their postcodes translated to map references. MAIN RESULTS: Significant birth proximity relative risks were found within 1.0 km of hotspots for carbon monoxide, PM10 particles, VOCs, nitrogen oxides, benzene, dioxins, 1,3-butadiene, and benz(a)pyrene. Calculated attributable risks showed that most child cancers and leukaemias are probably initiated by such exposures. CONCLUSIONS: Reported associations of cancer birth places with sites of industrial combustion, VOCs uses, and associated engine exhausts, are confirmed. Newly identified specific hazards include the known carcinogens 1,3-butadiene, dioxins, and benz(a)pyrene. The mother probably inhales these or related materials and passes them to the fetus across the placenta. (+info)
Mortality and greenhouse gas impacts of biomass and petroleum energy futures in Africa.
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We analyzed the mortality impacts and greenhouse gas (GHG) emissions produced by household energy use in Africa. Under a business-as-usual (BAU) scenario, household indoor air pollution will cause an estimated 9.8 million premature deaths by the year 2030. Gradual and rapid transitions to charcoal would delay 1.0 million and 2.8 million deaths, respectively; similar transitions to petroleum fuels would delay 1.3 million and 3.7 million deaths. Cumulative BAU GHG emissions will be 6.7 billion tons of carbon by 2050, which is 5.6% of Africa's total emissions. Large shifts to the use of fossil fuels would reduce GHG emissions by 1 to 10%. Charcoal-intensive future scenarios using current practices increase emissions by 140 to 190%; the increase can be reduced to 5 to 36% using currently available technologies for sustainable production or potentially reduced even more with investment in technological innovation. (+info)
Composition, toxicity, and mutagenicity of particulate and semivolatile emissions from heavy-duty compressed natural gas-powered vehicles.
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Particulate matter (PM) and vapor-phase semivolatile organic compounds (SVOC) were collected from three buses fueled by compressed natural gas. The bus engines included a well-functioning, conventional engine; a "high emitter" engine; and a new technology engine with an oxidation catalyst. Chemical analysis of the emissions showed differences among these samples, with the high emitter sample containing markers of engine oil constituents. PM + SVOC samples were also collected for mutagenicity and toxicity testing. Extraction efficiencies from the collection media were lower than for similarly collected samples from gasoline or diesel vehicles. Responses to the recovered samples were compared on the basis of exhaust volume, to incorporate the emission rates into the potency factors. Mutagenicity was assessed by Salmonella reverse mutation assay. Mutagenicity was greatest for the high emitter sample and lowest for the new technology sample. Metabolic activation reduced mutagenicity in strain TA100, but not TA98. Toxicity, including inflammation, cytotoxicity, and parenchymal changes, was assessed 24 h after intratracheal instillation into rat lungs. Lung responses were generally mild, with little difference between the responses to equivalent volumes of emissions from the normal emitter and the new technology, but greater responses for the high emitter. These emission sample potencies are further compared on the basis of recovered mass with previously reported samples from normal and high-emitter gasoline and diesel vehicles. While mutagenic potencies for the CNG emission samples were similar to the range observed in the gasoline and diesel emission samples, lung toxicity potency factors were generally lower than those for the gasoline and diesel samples. (+info)
Cleaning the air and improving health with hydrogen fuel-cell vehicles.
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Converting all U.S. onroad vehicles to hydrogen fuel-cell vehicles (HFCVs) may improve air quality, health, and climate significantly, whether the hydrogen is produced by steam reforming of natural gas, wind electrolysis, or coal gasification. Most benefits would result from eliminating current vehicle exhaust. Wind and natural gas HFCVs offer the greatest potential health benefits and could save 3700 to 6400 U.S. lives annually. Wind HFCVs should benefit climate most. An all-HFCV fleet would hardly affect tropospheric water vapor concentrations. Conversion to coal HFCVs may improve health but would damage climate more than fossil/electric hybrids. The real cost of hydrogen from wind electrolysis may be below that of U.S. gasoline. (+info)
Lung cancer and indoor pollution from heating and cooking with solid fuels: the IARC international multicentre case-control study in Eastern/Central Europe and the United Kingdom.
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Exposure to fuel from cooking and heating has not been studied in Europe, where lung cancer rates are high and many residents have had a long tradition of burning coal and unprocessed biomass. Study subjects included 2,861 cases and 3,118 controls recruited during 1998-2002 in the Czech Republic, Hungary, Poland, Romania, Russia, Slovakia, and the United Kingdom. The odds ratio of lung cancer associated with solid fuel use was 1.22 (95% confidence interval (CI): 1.04, 1.44) for cooking or heating, 1.37 (95% CI: 0.90, 2.09) for solid fuel only for cooking, and 1.24 (95% CI: 1.05, 1.47) for solid fuels used for both cooking and heating. Risk increased relative to the percentage of time that solid fuel was used for cooking (p(trend) < 0.0001), while no risk increase was detected for solid fuel used for heating. The odds ratio of lung cancer in whole-life users of solid cooking fuel was 1.80 (95% CI: 1.35, 2.40). Switching to nonsolid fuels resulted in a decrease in risk. The odds ratio for the longest duration of time since switching was 0.76 (95% CI: 0.63, 0.92). The data suggest a modest increased risk of lung cancer related to solid-fuel use for cooking rather than heating. (+info)
Evolution of carbon sinks in a changing climate.
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Climate change is expected to influence the capacities of the land and oceans to act as repositories for anthropogenic CO2 and hence provide a feedback to climate change. A series of experiments with the National Center for Atmospheric Research-Climate System Model 1 coupled carbon-climate model shows that carbon sink strengths vary with the rate of fossil fuel emissions, so that carbon storage capacities of the land and oceans decrease and climate warming accelerates with faster CO2 emissions. Furthermore, there is a positive feedback between the carbon and climate systems, so that climate warming acts to increase the airborne fraction of anthropogenic CO2 and amplify the climate change itself. Globally, the amplification is small at the end of the 21st century in this model because of its low transient climate response and the near-cancellation between large regional changes in the hydrologic and ecosystem responses. Analysis of our results in the context of comparable models suggests that destabilization of the tropical land sink is qualitatively robust, although its degree is uncertain. (+info)
Gas cooking and smoking habits and the risk of childhood and adolescent wheeze.
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The authors investigated the risk of wheezing illnesses in relation to contemporaneous pollutant exposures (gas cooking, heating, and smoking) in childhood and adolescence in a cohort of 2,289 United Kingdom subjects. Data from two questionnaires assessing wheezing at ages 7-8 and 15-17 years and one questionnaire on current and past pollutant exposures at age 16-18 years were studied (1987-1996). The 1,868 subjects returning all three questionnaires were divided into three groups representing childhood (10.5%), adolescent (10.9%), and persistent (i.e., both; 16.3%) wheezing and compared with 1,165 controls (62.4%) without wheezing. The estimated risks of childhood wheezing were increased by exposure to any gas in childhood (odds ratio (OR) = 1.47, 95% confidence interval (CI): 1.05, 2.04) and exposure to a gas hob in childhood (OR = 1.56, 95% CI: 1.13, 2.16) and were increased further in those persistently exposed. Risk of persistent wheezing in adolescence was paradoxically reduced by exposure to a gas hob (OR = 0.67, 95% CI: 0.50, 0.91), possibly because of selection avoidance. Contemporaneous exposure to combined smoking by both parents was associated with wheezing in all groups (odds ratios ranged from 1.62 (95% CI: 1.06, 2.46) to 1.93 (95% CI: 1.10, 3.38)). Maternal smoking alone was associated with persistent wheezing and with both childhood (OR = 1.90, 95% CI: 1.06, 3.39) and persistent (OR = 2.18, 95% CI: 1.15, 4.14) wheezing if smoking occurred throughout childhood and adolescence. The authors conclude that exposures to gas cooking and smoking in childhood and adolescence increase the overall risk of wheezing. (+info)
A direct approach to control short term population dynamics in time series studies.
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BACKGROUND: Short term population dynamics is an important issue in several epidemiological studies. Usually, calendar time or dummy variables are used to control indirectly for this confounding. This study tested a direct method. METHODS: The study compared as proxy variables of population dynamics the summer 2003 data of cooking gas consumptions, solid urban waste production, and television access for the municipality of Bologna (Italy). RESULTS: Solid urban waste production and television access data showed similar trends. Considerably different were the >65 year olds estimates with respect to total population based on television access. CONCLUSIONS: Television access data are probably the best indicator in the estimates of population dynamics in large or densely populated areas, especially because of the possibility of stratifications with respect to age. (+info)