Noah Scovronick

The health implications of fracking.

What is known about the health eff ects of gas extraction by induced hydraulic fracturing of gas-bearing rock— ie, fracking? A workshop held on Nov 15, 2013, at the London School of Hygiene and Tropical Medicine and attended by scientists, public health professionals, and decision makers addressed this question. Fracking is at a very early stage in the UK, with only one shale gas well tested so far. This situation provides an important opportunity to gather information and to conduct studies of health and environmental eff ects before any large-scale development. Scientifi c study of the health eff ects of fracking is in its infancy, but fi ndings suggest that this form of extraction might increase health risks compared with conventional oil and gas wells because of the larger surface footprints of fracking sites; their close proximity to locations where people live, work, and play; and the need to transport and store large volumes of materials. In the USA, where more than 52 000 shale gas wells have been drilled, data suggest that risks of environmental contamination occur at all stages in the development of shale gas extraction. Failure of the structural integrity of the well cement and casing, surface spills and leakage from above-ground storage, emissions from gasprocessing equipment, and the large numbers of heavy transport vehicles involved are the most important factors that contribute to environmental contamination and exposures in the USA. Environmental exposures include outdoor air pollutants (ie, volatile organic compounds, tropospheric ozone, and diesel particulate matter) and pollutants (ie, benzene, hydrocarbons, endocrine-disrupting chemicals, and heavy metals) in both ground and surface water. Known occupational hazards include airborne silica exposure at the well pad. Toxicological data for the chemicals injected into wells (so-called frac fl uid) indicate that many of them have known adverse eff ects on health, with no toxicological data available for some. Assessment of potential risks has been diffi cult in the USA because drilling operators are not required to disclose which chemicals are used, but the UK Government has accepted the recommendation from the Royal Society and Royal Academy of Engineering Working Group on shale gas extraction for full disclosure. Exposure and epidemiological studies—of which there are currently very few—are needed along the entire supply chain of shale gas to characterise and quantify associated health issues. The socioeconomic implications of shale gas development on local communities before, during, and after extraction, and how risks should be communicated, are also impor tant research priorities. In addition to local health and environment threats, an important consideration is the contribution of shale gas extraction to greenhouse-gas emissions and, thus, to climate change. Although there is confl icting evidence about the comparative contribution of lifecycle greenhouse gases of shale gas relative to coal, evidence from the USA indicates that instead of replacing coal, shale gas has rapidly become an additional source of fossil fuel, leading to an increase in cumulative global greenhouse-gas emissions. The degree to which shale gas extraction is developed should be based on comparisons with other energy options, including renewable energy sources, and greater investment in energy effi ciency measures, taking full account of environmental, economic, and health implications. Health impact assessments on fracking can provide evidence-based input at several levels of decision making in the UK’s regulatory framework, including in the formulation of national policy and in local planning processes. Information generated from health impact assessments can allow modifi cations to a project licence to reduce health eff ects. However, key issues for

The impact of housing type on temperature-related mortality in South Africa, 1996-2015.

This paper explores how housing modifies the temperature-mortality relationship in the Eastern and Western Cape provinces of South Africa. We estimate dose-response relationships for residents living in each of the five common types of South African housing by combining linear-threshold models for Cape Town with concurrent data on the citys housing composition and expert estimates of how well different types of housing protect against heat and cold. We then apply temperature data to determine provincial-level dose-response relationships, relative risks, attributable fractions and mortality burdens for heat and cold under seven housing scenarios--three past, three future and a scenario of maximum protection. We find that future mortality burdens would be lower under a policy scenario that prioritizes the replacement of informal housing compared to one that prioritizes the replacement of traditional dwellings. In a maximum protection scenario, where everyone lived in houses characteristic of the wealthy, temperature-related mortality could be reduced by over 50% (approximately 5000 deaths annually) in the two provinces combined. These results have relevance to current housing policy but also reinforce the importance of the built environment in mitigating adverse effects of future climate change.

Reduce short-lived climate pollutants for multiple benefits

Deep cuts in carbon dioxide emissions are urgently needed to prevent dangerous climate change, but they must be complemented by reductions in short-lived climate pollutants (SLCPs), which produce a strong global warming effect but have relatively brief atmospheric lifetimes (figure). SLCPs generally cause more radiative forcing per kg than carbon dioxide, and their mitigation could have a greater effect on climate change in the near term (in some cases almost immediately)—eg, by reducing the melting of snow and ice.

Climate change: how can epidemiology best inform policy?

Evidence that human activity affects global climate has stimulated a broad, important, and urgent research agenda. This agenda includes questions about human health that require the tools of epidemiology. Several publications have reviewed the health dimensions of the climate change research agenda. Our objective here is to map out the specific contributions within that context that epidemiology can make. Beyond proposing a general scheme of such contributions, we do not attempt to be comprehensive, preferring to highlight issues and offer examples that have received less attention.

Air Quality and Health Impacts of Future Ethanol Production and Use in São Paulo State, Brazil

It is often argued that liquid biofuels are cleaner than fossil fuels, and therefore better for human health, however, the evidence on this issue is still unclear. Brazil’s high uptake of ethanol and role as a major producer makes it the most appropriate case study to assess the merits of different biofuel policies. Accordingly, we modeled the impact on air quality and health of two future fuel scenarios in São Paulo State: a business-as-usual scenario where ethanol production and use proceeds according to government predictions and a counterfactual scenario where ethanol is frozen at 2010 levels and future transport fuel demand is met with gasoline. The population-weighted exposure to fine particulate matter (PM2.5) and ozone was 3.0 μg/m3 and 0.3 ppb lower, respectively, in 2020 in the scenario emphasizing gasoline compared with the business-as-usual (ethanol) scenario. The lower exposure to both pollutants in the gasoline scenario would result in the population living 1100 additional life-years in the first year, and if sustained, would increase to 40,000 life-years in year 20 and continue to rise. Without additional measures to limit emissions, increasing the use of ethanol in Brazil could lead to higher air pollution-related population health burdens when compared to policy that prioritizes gasoline.

Four issues in undernutrition-related health impact modeling

Undernutrition modeling makes it possible to evaluate the potential impact of such events as a food-price shock or harvest failure on the prevalence and severity of undernutrition. There are, however, uncertainties in such modeling. In this paper we discuss four methodological issues pertinent to impact estimation: (1) the conventional emphasis on energy intake rather than dietary quality; (2) the importance of the distribution of nutrient intakes; (3) the timing of both the ‘food shock’ and when the response is assessed; and (4) catch-up growth and risk accumulation.

An EcoHealth Forum in London: Young Researchers Fill a Training Gap

Despite an increasing recognition that addressing complex problems requires transdisciplinary research, the shortage of formal training for how to conduct such research is a major bottleneck to future progress. In response to this training gap, a group of early career scientists in London created the London EcoHealth Forum. Now in its second year, the Forum has matured into a small but dedicated group that cultivates thought and learning about ecosystem approaches to health. This paper discusses the key challenges faced while setting up the group and how they were overcome. The paper also outlines the main activity of the group, a seminar series devoted to a specific topic—the overconsumption of meat in London—and suggests that this format may be a useful tool for others who wish to set up a similar organization or teaching program.