Agnes Lobscheid

Grand Challenges for Life-Cycle Assessment of Biofuels

Biofuels are widely touted as viable, albeit not straightforward, alternatives to petroleum-derived fuels. To best determine their utilization, many practitioners turn to life-cycle assessment (LCA) to ascertain the “environmental footprint”. Although parameters such as resource and land use, along with infrastructure, can be incorporated into LCA algorithms, many have noted that the methodological approach still needs careful attention. In this Feature, McKone et al. outline seven grand challenges that need to be engaged and surmounted to provide the best way forward for biofuel use.

Association of Classroom Ventilation with Reduced Illness Absence: A Prospective Study in California Elementary Schools

Abstract Limited evidence associates inadequate classroom ventilation rates (VRs) with increased illness absence (IA). We investigated relationships between VRs and IA in California elementary schools over two school years in 162 3rd–5th‐grade classrooms in 28 schools in three school districts: South Coast (SC), Bay Area (BA), and Central Valley (CV). We estimated relationships between daily IA and VR (estimated from two year daily real‐time carbon dioxide in each classroom) in zero‐inflated negative binomial models. We also compared IA benefits and energy costs of increased VRs. All school districts had median VRs below the 7.1 l/s‐person California standard. For each additional 1 l/s‐person of VR, IA was reduced significantly (p<0.05) in models for combined districts (−1.6%) and for SC (−1.2%), and nonsignificantly for districts providing less data: BA (−1.5%) and CV (−1.0%). Assuming associations were causal and generalizable, increasing classroom VRs from the California average (4 l/s‐person) to the State standard would decrease IA by 3.4%, increase attendance‐linked funding to schools by

Lifecycle greenhouse gas implications of US national scenarios for cellulosic ethanol production

33 million annually, and increase costs by only

Quantifying the co-benefits of energy-efficiency policies: A case study of the cement industry in Shandong Province, China

4 million. Further increasing VRs would provide additional benefits. These findings, while requiring confirmation, suggest that increasing classroom VRs above the State standard would substantially decrease illness absence and produce economic benefits.

Contribution of locally grown foods in cumulative exposure assessments

The Energy Independence and Security Act of 2007 set an annual US national production goal of 39.7 billion l of cellulosic ethanol by 2020. This paper explores the possibility of meeting that target by growing and processing Miscanthus giganteus. We define and assess six production scenarios in which active cropland and/or Conservation Reserve Program land are used to grow to Miscanthus. The crop and biorefinery locations are chosen with consideration of economic, land-use, water management and greenhouse gas (GHG) emissions reduction objectives. Using lifecycle assessment, the net GHG footprint of each scenario is evaluated, providing insight into the climate costs and benefits associated with each scenario’s objectives. Assuming that indirect land-use change is successfully minimized or mitigated, the results suggest two major drivers for overall GHG impact of cellulosic ethanol from Miscanthus: (a) net soil carbon sequestration or emissions during Miscanthus cultivation and (b) GHG offset credits for electricity exported by biorefineries to the grid. Without these factors, the GHG intensity of bioethanol from Miscanthus is calculated to be 11‐13 g CO2-equivalent per MJ of fuel, which is 80‐90% lower than gasoline. Including soil carbon sequestration and the power-offset credit results in net GHG sequestration up to 26 g CO2-equivalent per MJ of fuel.

Intake fractions of primary conserved air pollutants emitted from on-road vehicles in the United States

In 2010, Chinas cement industry accounted for more than half of the worlds total cement production. The cement industry is one of the most energy-intensive and highest carbon dioxide (CO2)-emitting industries, and thus a key industrial contributor to air pollution in China. For example, it is the largest source of particulate matter (PM) emissions in China, accounting for 40% of industrial PM emissions and 27% of total national PM emissions. In this study, we quantify the co-benefits of PM10 and sulfur dioxide (SO2) emission reductions that result from energy-saving measures in the cement industry in Shandong Province, China. We use a modified form of the cost of conserved energy (CCE) equation to incorporate the value of these co-benefits. The results show that more than 40% of the PM and SO2 emission reduction potential of the electricity-saving measures is cost effective even without taking into account the co-benefits for the electricity-saving measures. The results also show that including health benefits from PM10 and/or SO2 emission reductions reduces the CCE of the fuel-saving measures. Two measures that entail changing products (production of blended cement and limestone Portland cement) result in the largest reduction in CCE when co-benefits were included, since these measures can reduce both PM10 and SO2 emissions, whereas the other fuel-saving measures do not reduce PM10.

Exploring relationships between outdoor air particulate-associated polycyclic aromatic hydrocarbon and PM2.5: A case study of benzo(a)pyrene in California metropolitan regions

Both laboratory and field studies confirm the importance of vegetation for scavenging semivolatile organic chemicals (SVOCs) from the atmosphere and a number of exposure studies have found that the dietary pathway is often a significant contributor to cumulative exposure for these chemicals. However, little information exists on the atmospheric source-to-dietary intake linkage for SVOCs. Because of higher SVOC emissions to urban regions, this linkage is particularly important for foods that are grown, distributed and consumed in or near urban regions. The food pathway can also contribute to dietary exposure for populations that are remote from a pollutant source if the pollutants can migrate to agricultural regions and subsequently to the agricultural commodities distributed to that population. We use available data, the characteristic travel distance, and the CalTOX multimedia model framework to assess the contribution of local sources of food to cumulative SVOC intake. Based on published concentration data for foods, our exposure calculations indicate that the potential intake through ingestion can be up to 1000 times that of inhalation for certain persistent SVOCs. We use the population-based intake fraction (iF) to determine how SVOC intake can vary among food commodities and exposure pathways, and to determine the contribution of airborne emitted SVOCs to the diet in the Northern Hemisphere. We focus on three representative multimedia SVOCs-benzo(a)pyrene, fluoranthene, and 2,3,7,8-tetrachlorodibenzo-p-dioxin. The approach presented here provides a useful framework and starting point for source-to-intake assessments for the ambient air-to-dietary exposure pathway.