Evaluation of exposure reduction to indoor air pollution in stove intervention projects in Peru by urinary biomonitoring of polycyclic aromatic hydrocarbon metabolites

Burning biomass fuels such as wood on indoor open-pit stoves is common in developing regions. In such settings, exposure to harmful combustion products such as fine particulate matter (PM(2.5)), carbon monoxide (CO) and polycyclic aromatic hydrocarbons (PAHs) is of concern. We aimed to investigate if the replacement of open pit stoves by improved stoves equipped with a chimney would significantly reduce exposure to PAHs, PM(2.5) and CO. Two stove projects were evaluated in Peru. Program A was part of the Juntos National Program in which households built their own stoves using materials provided. In Program B, Barrick Gold Corporation hired a company to produce and install the stoves locally. A total of 30 and 27 homes participated in Program A and B, respectively. We collected personal and kitchen air samples, as well as morning urine samples from women tasked with cooking in the households before and after the installation of the improved stoves. Median levels of PM(2.5) and CO were significantly reduced in kitchen and personal air samples by 47-74% after the installation of the new stoves, while the median reduction of 10 urinary hydroxylate PAH metabolites (OH-PAHs) was 19%-52%. The observed OH-PAH concentration in this study was comparable or higher than the 95th percentile of the general U.S. population, even after the stove intervention, indicating a high overall exposure in this population.     

The Role of Wetlands for Mitigating Economic Damage from Hurricanes

Coastal communities along the United States coast often experience significant economic damage resulting from the impacts of tropical storms and hurricanes. Research suggests that certain factors that affect economic damages are increasing the vulnerability of coastal communities. Population growth, which increases vulnerability by placing valuable lives and assets in the path of storms, is expected to increase. Climate change has the potential to cause more frequent and intense storms, and coastal wetland loss is contributing to the vulnerability of coastal populations. Wetlands conservation and restoration is often advocated for as a means of reducing the impacts of coastal storms. The relationship between wetlands and storm surge energy is understood relatively well in physical terms, but very little economic analysis has been conducted to estimate the degree to which wetlands reduce economic impacts. Using factor analysis, the relationships among coastal populations, wetlands, storm intensity, and economic damage are explored. The factor analysis suggests that wetland presence is associated with a reduction in economic damages from coastal storms. Factor score analysis suggests that the proportion of damage explained by wetland presence is smaller for more intense storms. These results are consistent with those found in the physical science literature and have potentially large consequences for how wetlands are used in risk reduction.     

The states of public opinion on the environment

State-level public opinion on the environment within the US is examined, using data from the General Social Survey (GSS) from 2000 to 2010. A Multilevel Regression and Post-Stratification (MRP) approach is taken to estimate three different survey items on environmental issues at the US state level. This allows for a comparable understanding of state-level public opinion on environmental issues, which is then connected to economic, environmental, and political conditions, and representation in policy making. The findings indicate the MRP technique is a sophisticated way to make accurate estimations of state-level public opinion, and those estimates provide further insight into the shaping of public opinion and public policy.     

Adsorption of trace metals to plastic resin pellets in the marine environment

Plastic production pellets collected from beaches of south west England contain variable concentrations of trace metals (Cr, Co, Ni, Cu, Zn, Cd and Pb) that, in some cases, exceed concentrations reported for local estuarine sediments. The rates and mechanisms by which metals associate with virgin and beached polyethylene pellets were studied by adding a cocktail of 5 μg L(-1) of trace metals to 10 g L(-1) pellet suspensions in filtered seawater. Kinetic profiles were modelled using a pseudo-first-order equation and yielded response times of less than about 100 h and equilibrium partition coefficients of up to about 225 ml g(-1) that were consistently higher for beached pellets than virgin pellets. Adsorption isotherms conformed to both the Langmuir and Freundlich equations and adsorption capacities were greater for beached pellets than for virgin pellets. Results suggest that plastics may represent an important vehicle for the transport of metals in the marine environment.     

Green pre-concentration techniques during pesticide analysis in food samples

The ever-increasing demand for determining pesticides at low concentration levels in different food matrices requires a preliminary step of pre-concentration which is considered a crucial stage. Recently, the parameter of “greenness” during sample pre-concentration of pesticides in food matrices is as important as selectivity in order to avoid using harmful organic solvents during sample preparation. Developing new green pre-concentration techniques is one of the key subjects. Thus, to reduce the impact on the environment during trace analysis of pesticides in food matrices, new developments in pre-concentration have gone in three separate directions: the search for more environmentally friendly solvents, miniaturization and development of solvent-free pre-concentration techniques. Eco-friendly solvents such as supercritical fluids, ionic liquids and natural deep eutectic solvents have been developed for use as extraction solvents during pre-concentration of pesticides in food matrices. Also, miniaturized pre-concentration techniques such as QuEChERS, dispersive liquid–liquid micro-extraction and hollow-fiber liquid-phase micro-extraction have been used during trace analysis of pesticides in food samples as well as solvent-free techniques such as solid-phase micro-extraction and stir bar sorptive extraction. All these developments which are aimed at ensuring that pesticide pre-concentration in different food matrices is green are critically reviewed in this paper.     

Effectiveness and kinetics of ferrate as a disinfectant for ballast water

This study examined whether ferrate could meet the international standards for successful ballast water treatment, including final concentrations of less than 1 CFU/mL of Enterococci, less than 2.5 CFU/mL of Escherichia coli, and less than 1 CFU/100 mL of Vibrio cholerae. Pure cultures of E. coli, Klebsiella pneumoniae, and V. cholerae, and a mixed culture of Enterococcus faecium and E. faecilis were grown in saline solution to simulate ballast water and were treated with dosages of ferrate ranging from 0.25 to 5.0 mg/L. A ferrate dose of 5 mg/L resulted in complete disinfection of all organisms tested, and smaller dosages were also very effective. Tailing was consistently observed, and the Hom's model (1972) appeared to most accurately represent the action of ferrate on these organisms. Salinity and pH did not adversely affect results, and regrowth was not a problem. Ferrate shows good potential as an effective disinfectant in the treatment of ballast water.     

Impact of clouds and aerosols on ozone production in Southeast Texas

A radiative transfer model and photochemical box model are used to examine the effects of clouds and aerosols on actinic flux and photolysis rates, and the impacts of changes in photolysis rates on ozone production and destruction rates in a polluted urban environment like Houston, Texas. During the TexAQS-II Radical and Aerosol Measurement Project the combined cloud and aerosol effects reduced j(NO₂) photolysis frequencies by nominally 17%, while aerosols reduced j(NO₂) by 3% on six clear sky days. Reductions in actinic flux due to attenuation by clouds and aerosols correspond to reduced net ozone formation rates with a nearly one-to-one relationship. The overall reduction in the net ozone production rate due to reductions in photolysis rates by clouds and aerosols was approximately 8 ppbv h^?1.     

Heterogeneous conversion of nitric acid to nitrous acid on the surface of primary organic aerosol in an urban atmosphere

Nitrous acid (HONO), nitric acid (HNO₃), and organic aerosol were measured simultaneously atop an 18-story tower in Houston, TX during August and September of 2006. HONO and HNO₃ were measured using a mist chamber/ion chromatographic technique, and aerosol size and chemical composition were determined using an Aerodyne quadrupole aerosol mass spectrometer. Observations indicate the potential for a new HONO formation pathway: heterogeneous conversion of HNO₃ on the surface of primary organic aerosol (POA). Significant HONO production was observed, with an average of 0.97 ppbv event^?1 and a maximum increase of 2.2 ppb in 4 h. Nine identified events showed clear HNO₃ depletion and well-correlated increases in both HONO concentration and POA-dominated aerosol surface area (SA). Linear regression analysis results in correlation coefficients (r²) of 0.82 for HONO/SA and 0.92 for HONO/HNO₃. After correction for established HONO formation pathways, molar increases in excess HONO (HONO_excess) and decreases in HNO₃ were nearly balanced, with an average HONO_excess/HNO₃ value of 0.97. Deviations from this mole balance indicate that the residual HNO₃ formed aerosol-phase nitrate. Aerosol mass spectral analysis suggests that the composition of POA could influence HONO production. Several previously identified aerosol-phase PAH compounds were enriched during events, suggesting their potential importance for heterogeneous HONO formation.     

Mercury species measured atop the Moody Tower TRAMP site,Houston, Texas

Atmospheric mercury speciation was monitored within Houston, Texas, USA, August 6–October 14, 2006 as part of the TexAQS Radical and Aerosol Measurement Program (TRAMP). On average, all mercury levels were significantly elevated compared to a rural Gulf of Mexico coastal site. Concentrations varied from very clean to very dirty. Multi-day periods of stagnant or low-wind conditions brought elevated concentrations of all mercury species, whereas multi-day periods of strong winds, particularly southerly winds off the Gulf of Mexico, brought very low values of mercury species. Over the entire mercury measurement period, the daily averages of mercury species showed distinct and consistent relationships with the average planetary boundary layer dynamics, with gaseous elemental and particulate-bound mercury near-surface concentrations enhanced by a shallow nocturnal boundary layer, and reactive gaseous mercury concentration enhanced by midday convective boundary layer air entrainment transporting air aloft to the surface. Mercury concentrations were not significantly correlated with known products of combustion, likely indicating non-combustion mercury sources from the Houston area petrochemical complexes. On the morning of August 31, 2006 an observed emission event at a refinery complex on the Houston Ship Channel resulted in extremely high concentrations of aerosol mass and particulate-bound mercury at the TRAMP measurement site 20 km downwind.