CHINA: Stench of Air Pollution Soars unabated

Residents of Beijing and many other cities in China were warned to stay inside in mid-January 2013 as the nation faced one of the worst periods of air quality in recent history.

The Chinese government ordered factories to scale back emissions, while hospitals saw spikes of more than 20 to 30 percent in patients complaining of respiratory issues, according to news reports.

At the time that this Jan. 14 image was taken by satellite, ground-based sensors at the U.S. Embassy in Beijing reported PM2.5 measurements of 291 micrograms per cubic meter of air.

Fine, airborne particulate matter (PM) that is smaller than 2.5 microns (about one thirtieth the width of a human hair) is considered dangerous because it is small enough to enter the passages of the human lungs.

Most PM2.5 aerosol particles come from the burning of fossil fuels and biomass (wood fires and agricultural burning). The World Health Organization (WHO) considers PM2.5 to be safe when it is below 25.

Also at the time of the image, the air quality index (AQI) in Beijing was 341. An AQI above 300 is considered hazardous to all humans, not just those with heart or lung ailments. AQI below 50 is considered good.

On January 12, the peak of the current air crisis, AQI was 775 the U.S Embassy Beijing Air Quality Monitor—off the U.S. Environmental Protection Agency scale—and PM2.5 was 886 micrograms per cubic meter.

› View image comparisons with annotations.

Image Credit: NASA/Terra - MODIS

Rodent Defense: Rat daubs fur with poison-arrow plant toxins

The deadly secret of a rat that kills lions and jackals has at last been revealed. 

Unlike some mammals that produce their own toxins, the African crested rat is the first known to protect itself by daubing its fur with poisons from plants. 

The same lethal toxins are used by African tribal hunters to coat their arrow-tips.

Suspecting that Lophiomys imhausi may obtain toxins from chewing on the bark of the poison-arrow plant, acokanthera, Fritz Vollrath of the University of Oxford and his team offered some to a captive animal. 

Over the course of a week, it periodically chewed the bark then smeared its saliva over a section of short hairs that lies along its flank, hidden inside its fur.

Placing the hairs under a microscope revealed that their surface is perforated. Each also contains fibres at its core, allowing it to soak up the toxins and store them.

Vollrath says the findings tally with reports that when attacked, the rat stands its ground, parts its fur to reveal the stripe of poisonous hair, and invites the aggressor to bite its flank. 

Aggressors who do go in for the kill have been seen to shrink back, froth at the mouth and often collapse and die, apparently from heart failure.

The rats are also known to have abnormally thick skins and skulls, which probably evolved so that they could survive attacks until the poison kicks in. They have also – clearly – evolved immunity to the toxins.

Journal reference: Proceedings of the Royal Society B, DOI: 10.1098/rspb.2011.1169

Learning Difficulties: Exposure to Pesticides in Womb

Babies exposed to high levels of pesticides while in the womb may suffer from learning problems, a new study suggests.

The study focused on a chemical called permethrin, one of the pyrethroid pesticides, commonly used in agriculture and to kill termites, fleas and household bugs, says lead author Megan Horton of the Columbia Center for Children's Environmental Health. 

Most of the pregnant women in this New York-based study were exposed by spraying for cockroaches.

Permethrin — among the most commonly detected pesticides in homes — is being used more often today as older organophosphorous pesticides are phased out because of concerns that they harm brain development, says Horton, whose study is being published today in Pediatrics.

Researchers measured 348 pregnant women's exposures by asking them to wear backpack air monitors, Horton says. Researchers followed the women and their children for three years.

Children exposed to the highest pesticide levels before birth were three times as likely to have a mental delay compared to children with lower levels, the study says. 

Children with the highest prenatal exposures also scored about 4 points lower on an intelligence test, the Bayley Mental Developmental Index. That test has a mean score of 100, with most people's scores falling within 15 points of that range.

That's about the same intelligence loss caused by lead, says Philip Landrigan, a pediatrics professor and environmental health expert at New York's Mount Sinai School of Medicine.

Pyrethroid pesticides kill bugs by "being toxic to the developing brain," Landrigan says. The results are "very believable and should be taken seriously," Landrigan says.

Because the study is the first to link permethrin with brain damage, researchers need to conduct additional studies before concluding that the pesticide really harms the brain, says Mary Fox, an assistant professor at John Hopkins' Bloomberg School of Public Health.

Even without definitive data, however, Fox says it makes sense for pregnant women to reduce their exposure to bug sprays and other pesticides.

To control bugs, for example, she suggests fixing water leaks, keeping food tightly covered and, if necessary, spraying outside instead of inside the home.

Addicted to Risk - Naomi Klein TED Video

Red Martian Powder is invasive and may be poisonous to human life

Clingy Red Martian Powder is a real Martian menace for NASA and the Rovers. (Image: NASA/JPL-Caltech)

Mars Rover Stuck

THE Mars rover Spirit, now bogged down in the Red Planet's soil, will need all the power it can muster if NASA scientists manage to get it moving again. So it's timely that researchers are getting a handle on why, the fine powdery dust is so invasive. It has collected on the vehicle's solar panels and stubbornly refuses to be cleared.

Martian Powdery Dust

Although the Astronauts on the Moon landing found the dust there to be very clingy, the Martian powdery dust is particularly invasive. This was noticed more than a decade ago when surprisingly large amounts stuck to the wheels of NASA's Sojourner rover. Static electricity was thought to be to blame, but no one could explain how the particles became charged. Now a team led by Keith Forward of Case Western Reserve University in Cleveland, Ohio, have an answer.

Static Electricity

The team believe that electrons jump back and forth between the dust grains as they collide in the ever-present Martian winds and dust devils, providing a build up of static. Smaller grains would be more likely to retain their extra electrons, giving them a negative charge, while larger grains would be left positively charged. To prove this they electrically charged grains of Hawaiian volcanic ash, chosen for its similarity to Martian dust, by blowing them around in a container (Geophysical Research Letters, DOI: 10.1029/2009gl038589).

Powdery Dust Toxicity

William Farrell of NASA's Goddard Space Flight Center in Maryland says this may help to combat the dust - important if people travel to Mars. "If the dust is toxic and you bring it inside [a human habitat] it could be extraordinarily bad." So, there is a lot more work to be done yet and even if the powdery dust is not toxic, it will be detrimental to human health if it invades the lungs.