2011 November 22 Tuesday
Tailpipe Exhaust Damages Brain Cells

A Wall Street Journal article reports on accumulating evidence that particulates from car and truck exhausts damage brain cells.

As roadways choke on traffic, researchers suspect that the tailpipe exhaust from cars and trucks—especially tiny carbon particles already implicated in heart disease, cancer and respiratory ailments—may also injure brain cells and synapses key to learning and memory.

This is an argument for accelerating the development of batteries for electric vehicles. It is also an argument for working from home or living closer to work to reduce the time you spend breathing vehicle exhaust in your car. Ditto for driving to work very early.

Parenthetically, the amount of smoke I've seen gushing out of a diesel commuter passenger train is disgusting. Are train emissions regulations less strict than truck emissions regulations?

One problem with diesel trucks: they last a long time. So while in recent years emissions regulations for trucks have gotten much tighter we are going to have to wait decades for the older and higher polluting trucks to wear out. Outfitting the older trucks with newer emissions control equipment would be money well spent.

One thing you can do: See if your car has a cabin air filter (note, that PDF is only thru 2007 models and might not be complete) and replace it when dirty. Some filters are easy to replace, others require skill and time. Here's a Prius owners chat on cabin air filter replacement. Note that these filters are not HEPA level. So they are limited but better than nothing.

You can find portable HEPA filters that can plug into ashtray power. If you don't mind basically giving up a seat for an air filter you can get more benefit. But I've read online discussions about the rate of turn-over of cabin air per hour (Air Changes per Hour or ACH) where one participant says the portable HEPA filters can't pump air thru fast enough to keep up in the rate at which air comes in from the outside. But when stuck in traffic the air comes in more slowly and at a lower air quality. Such a filter might work better when it is most needed.

Does any OEM offer a HEPA filter option or some other claim to better air quality thru filtering?

By Randall Parker    2011 November 22 08:39 PM   Entry Permalink | Comments (21)
2009 September 15 Tuesday
Air Pollution Raises Blood Pressure

The quality of the air you breathe plays a role in determining whether you get high blood pressure.

ANN ARBOR, Mich. – It’s well known that measures such as exercise, a healthy diet and not smoking can help reduce high blood pressure, but researchers at the University of Michigan Health System have determined the very air we breathe can be an invisible catalyst to heart disease. Inhaling air pollution over just two hours caused a significant increase in diastolic blood pressure, the lower number on blood pressure readings, according to new U-M research.

People placed in air similar to that near an urban roadway experienced higher blood pressure. This is, parenthetically, an argument against doing long commutes in urban environments. The air you breathe in your car is bad for your health.

Eighty-three people in Ann Arbor and Toronto were involved in testing and breathed air pollution, concentrated by a mobile air quality research facility, that was similar to what would be found in an urban environment near a roadway.

“We looked at their blood vessels and then their responses before and after breathing high levels of air pollution,” explains Robert Bard, M.S., co-author and clinical research manager at U-M.

Ozone gases, a well-known component of air pollution, were not the biggest culprit. Rather, small microscopic particles about a 10th of the diameter of a human hair caused the rise in blood pressure and impaired blood vessel function, tests showed. The blood pressure increase was rapid and occurred within 2 hours, while the impairment in blood vessel function occurred later but lasted as long as 24 hours.

I'd like to know more about indoor air pollution and background air pollution for those who do not necessarily live near a highway. Would a home HEPA filter deliver real health benefits for most people? If you live in a city or near a busy street or freeway the argument for filtering one's air is more compelling.

By Randall Parker    2009 September 15 09:28 PM   Entry Permalink | Comments (5)
2007 July 28 Saturday
Diesel Particulates Plus Cholesterol Equals Inflammation

Diesel particulate pollution works synergistically with cholesterol to increase gene expression for genes involved in inflammation.

Got high cholesterol? You might want to stay away from air pollution.

That's the message of a new UCLA study linking diesel exhaust to atherosclerosis, or hardening of the arteries, which significantly increases one's risk for heart attack and stroke. Published in the July 26 edition of the online journal Genome Biology, the findings are the first to explain how fine particles in air pollution conspire with artery-clogging fats to switch on the genes that cause blood vessel inflammation and lead to cardiovascular disease.

"When you add one plus one, it normally totals two," said principal investigator Dr. André Nel, chief of nanomedicine at the David Geffen School of Medicine at UCLA and a researcher at UCLA's California NanoSystems Institute. "But we found that adding diesel particles to cholesterol fats equals three. Their combination creates a dangerous synergy that wreaks cardiovascular havoc far beyond what's caused by the diesel or cholesterol alone."

At the moment a battle is raging in Sacramento about a regulatory change to require construction companies and other operators of off-road diesel equipment to gradually upgrade or retire diesels that emit lots of particulates and other pollutants. The emissions restrictions for diesel cars are much tougher than the restrictions for off-road equipment. Well, diesel pollutants really are bad for human health and the polluters have been allowed to pollute for far too long.

Cells from human blood vessels were exposed to diesel particulates and

"Diesel particles are coated in chemicals containing free radicals, and the fatty acids in LDL cholesterol generate free radicals during metabolism in the cells," said first author Ke Wei Gong, a UCLA cardiology researcher. "We wanted to measure what happens when these two sources of oxidation come into contact."

The scientists combined the pollutants and oxidized fats and cultured them with cells from the inner lining of human blood vessels. A few hours later, the team extracted DNA from the cells for genetic analysis.

"We saw that the diesel particles and oxidized fats had worked in tandem to activate the genes that promote cellular inflammation — a major risk factor for atherosclerosis," said Dr. Jesus Araujo, UCLA assistant professor of medicine and director of environmental cardiology at the Geffen School of Medicine.

"The interaction left a genetic footprint that reveals how interaction between the particles and cholesterol accelerates the narrowing and blockage of the blood vessels," Araujo noted.

Now you might be saying that cell culture studies often do not reflect what happens in whole organisms. True enough. But these scientists saw similar gene expression changes when they repeated the experiment with live mice.

To duplicate these findings in living cells, the UCLA team exposed mice with high cholesterol to the diesel particles and saw activation of some of the same gene groups in the animals' tissue.

Do not live near highways. Do not live in areas with high levels of air pollution. If you must then consider installing a particulate air filter.

By Randall Parker    2007 July 28 09:30 PM   Entry Permalink | Comments (1)
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