If drivers switch from gasoline to biofuels, will it lessen the air pollution that shrouds cities around the world? Studies of auto emissions have indicated it might. But the first citywide air quality study of its kind, reported at the meeting, suggests that unless more than 26% of cars make the switch, it will have negligible effect.

doi: http://dx.doi.org/10.1126/science.336.6079.292-c

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At four locations in and around Monterey Bay, California, the researchers, using equipment that slurps up large quantities of air and retains any suspended particles, collected large volumes of fog droplets from June through August 2011. In the 25 samples they analyzed, concentrations of all forms of mercury averaged 10.7 nanograms per liter, and levels of monomethyl mercury averaged 3.4 nanograms per liter, they reported last month in Geophysical Research Letters. The latter concentration, the first such measurement ever reported from fog water, “is about five times the highest concentration ever seen in rainwater,” Weiss-Penzias notes. Using data from previous studies, including those of other teams, the researchers estimated that between 61% and 99% of the monomethyl mercury deposited in coastal ecosystems around Monterey Bay over the course of a year comes from fog.

The new findings don’t offer any ideas for minimizing mercury exposures in coastal environments, Weiss-Penzias says, but they do allow scientists to better understand how mercury may be making its way into those ecosystems. Future experiments, he says, will include measuring mercury levels in creatures at the base of the food chain, such as insects that may be drinking mercury-tainted fog droplets that have condensed on coastal plants.

doi: http://dx.doi.org/10.1029/2011GL050324

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The possible role of ammonia in a future energy infrastructure is discussed. The review is focused on the catalytic decomposition of ammonia as a key step. Other aspects, such as the catalytic removal of ammonia from gasification product gas or direct ammonia fuel cells, are highlighted as well. The more general question of the integration of ammonia in an infrastructure is also covered.

DOI: http://dx.doi.org/10.1039/C2EE02865D

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Following a 2007 Supreme Court ruling, the U.S. Environmental Protection Agency (EPA) today proposed the first Clean Air Act standard for carbon pollution from new power plants. EPA’s proposed standard reflects the ongoing trend in the power sector to build cleaner plants that take advantage of American-made technologies, including new, clean-burning, efficient natural gas generation, which is already the technology of choice for new and planned power plants. At the same time, the rule creates a path forward for new technologies to be deployed at future facilities that will allow companies to burn coal, while emitting less carbon pollution. The rulemaking proposed today only concerns new generating units that will be built in the future, and does not apply to existing units already operating or units that will start construction over the next 12 months.

Prior to developing this standard, EPA engaged in an extensive and open public process to gather the latest information to aid in developing a carbon pollution standard for new power plants. The agency is seeking additional comment and information, including public hearings, and will take that input fully into account as it completes the rulemaking process. EPA’s comment period will be open for 60 days following publication in the Federal Register.

More information: http://epa.gov/carbonpollutionstandard/

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There have been few studies concerning cyanotoxins in desert environments, compared with the multitude of studies of cyanotoxins in aquatic environments. However, cyanobacteria are important primary producers in desert environments, where after seasonal rains they can grow rapidly both stabilising and fertilising arid habitats. Samples of cyanobacteria from wadis – dry, ephemeral river beds – and sabkha – supertidal salt flats – in Qatar were analysed for the presence of microcystins, nodularin, anatoxin-a, cylindrospermopsin and anatoxin-a(S). Microcystins were detected by HPLC-PDA and ELISA at concentrations between 1.5 and 53.7 ng g− 1 dry wt of crust. PCR products for the mycD gene for microcystin biosynthesis were detected after amplification of DNA from desert crust samples at two out of three sample sites. The presence of anatoxin-a(S) was also indicated by acetylcholine esterase inhibition assay. As a function of area of desert crust, microcystin concentrations were between 3 and 56 μg m− 2. Based on the concentration of microcystins detected in crust, with reference to the published inhalation NOAEL and LOAEL values via nasal spray inhalation of purified microcystin-LR in aqueous solution, and the amount of dust potentially inhaled by a person from these dried crusts, the dose of microcystins could exceed a calculated TDI value of 1–2 ng kg− 1 day− 1 for an average adult. The presence of microcystins, and potentially of anatoxin-a(S), in desert crusts has important implications for human health. Further studies are required to monitor desert dust storms for the presence of cyanotoxins. An understanding of the risks of inhaling particles containing cyanotoxins is also warranted.

http://dx.doi.org/10.1016/j.scitotenv.2012.01.053

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After a year-long process of peer review, the DEMS scientists recently turned over to industry and others copies of two major papers they planned to publish in the Journal of the National Cancer Institute. The mining coalition made no official reply, but in mid-February, as the 90-day waiting period began to wane, Henry Chajet, a Washington D.C.-based lawyer and lobbyist for the Mining Awareness Resource Group (MARG), a party in the court cases, sent a letter to at least four science journals warning them that they risked unspecified consequences if they published the study. (For more on Chajet’s letter, and the background of the case, see this post.)Today marks the 91st day after the DEMS scientists submitted to JNCI. With the legal case still ongoing (it’s currently on appeal in a federal court in New Orleans) and the possibility of future complications, DEMS scientists wasted no time publishing either paper (available here and here; NCI and NIOSH also summarized the results here and here).

Daylight at Last for Study of Diesel Lung Cancer Risks – ScienceInsider

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