Archives for posts with tag: air pollution

From Los Angeles Times:

To understand the latest brouhaha about safe levels of ozone, it helps to understand the difference between science and policy.

First the back story. In 2008, the administrator of the U.S. Environmental Protection Agency, Stephen Johnson, reduced the allowable level of ozone in the air from 84 parts per billion to 75 ppb. Johnson said the change would lead to cleaner air and improve public health.

However, the EPA’s independent advisory panel had recommended that the limit be set even lower, in the range of 60 ppb to 70 ppb. Critics, including scientists, environmental advocates and medical associations, such as the American Thoracic Society, accused Johnson and the George W. Bush administration of prioritizing the economic concerns of polluters over the interests of the general public.

Depending on your point of view, you may see things Johnson’s way or you may side with his critics. But the process worked exactly as it was supposed to, with scientists analyzing the data and policymakers exercising their authority to take other factors into consideration, says Dr. Roger McClellan, a toxicologist and former chairman of the EPA’s Clean Air Scientific Advisory Committee. “They were an advisory panel, not a standard-setting panel,” he says.

Fast-forward to the Obama administration. Lisa Jackson is now the EPA administrator, and she wanted to revisit the ozone standard. She asked the current members of the advisory panel to take another look at the data, and they agreed with the previous panel’s conclusion that lowering the standard to between 60 ppb and 70 ppb range would have beneficial effects on public health. In a 2010 regulatory impact analysis report, the agency estimated that setting the limit at 70 ppb would prevent about 2,200 heart attacks, 23,000 asthma attacks and between 1,500 and 4,300 premature deaths each year; a limit of 60 ppb would avert 5,300 heart attacks, 58,000 asthma attacks and 4,000 to 12,000 premature deaths.

So this month, when President Obama put the kibosh on any reconsideration of the ozone standard, all those who railed before railed again.

The Clean Air Act mandates that the standards for certain pollutants, including ozone, be revisited every five years. So even as the advisory panel was digging into the old reports to answer Jackson’s queries, its members have also started reviewing more recent evidence for 2013, says the current committee chairman, Dr. Jonathan Samet, professor of preventive medicine at USC’s Keck School of Medicine.

Here’s a closer look at the scientific case against ozone.

What is ozone?

Ozone is the main component of smog and is created when certain volatile chemicals emitted from cars and factories react with sunlight. The ozone level in Southern California frequently is higher than the EPA standard, with the South Coast Air Basin out of compliance on 109 days last year, according to the South Coast Air Quality Management District.

How is ozone harmful to health?

Ozone is a gas that you inhale with the surrounding air. It can cause irritation and inflammation of the airways as well as coughing and shortness of breath. These effects depend on the concentration of ozone in the air you’re breathing, how rapidly and deeply you’re breathing and your own sensitivity to the pollutant.

Researchers have documented wide variability in people’s symptoms when they are exposed to controlled levels of ozone. These experiments usually have young, healthy nonsmokers breathing high concentrations of ozone — greater than 80 ppb and sometimes as high as 120 ppb — for six to eight hours. Subjects spend up to half of that time exercising, forcing them to inhale more of the pollutant.

The EPA panel said it was a “scientific certainty” that under these conditions, ozone decreases lung function (as measured by the amount of air a person breathes out when exhaling as hard as possible). The decline, of at least 10%, may sound small, but it is considered “clinically relevant,” according to the American Thoracic Society. Even when ozone levels were only 60 ppb, one study found that two out of 30 healthy subjects had at least a 10% decrease in lung function and six others showed symptoms of respiratory distress. That report was published in 2006 in the journal Inhalation Toxicology.

Who is most at risk?

The problem worsens for certain groups of people, notably children, seniors and those with asthma or other respiratory health issues.

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What are the public health consequences of having too much ozone?

Researchers in real-world settings have correlated ozone-level spikes to increased mortality and greater numbers of emergency room visits for respiratory problems.

For example, Delfino and his colleagues studied more than 23,000 emergency room admissions at 25 Montreal hospitals in the summer of 1993. They found that on days after the ozone level was at or above the average of 36 ppb, the number of older patients with respiratory symptoms who came to the ER jumped by 21%. However, ER visits for patients younger than 64 with respiratory symptoms or for patients with other kinds of health problems did not vary with ozone level. The results were published in the American Journal of Respiratory and Critical Care Medicine.

“Hundreds of similar studies have been done throughout the world,” Delfino says.

More.

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From Leadership:

Why are some people predisposed to being anxious, overweight or asthmatic? Why are some of us prone to heart attacks, diabetes or high blood pressure? You may say it’s our genes. Or our childhood experiences: How we were treated especially during those crucial first three years. Or maybe our well-being stem from lifestyle choices we make as adults, like our diet and how much exercise we get.

But what about your life in the womb? The nutrition you received; the pollutants, medicines and infections you were exposed to; your mother’s health, stress and state of mind while she was pregnant with you – pioneers in the controversial field of fetal origins say these factors shaped you as a baby – and for the rest of your life.

They assert the nine months in the womb permanently influence the wiring of the brain, the functioning of organs such as the heart, liver and pancreas, how prone we are to disease, our appetite and metabolism, our intelligence and temperament.

Much of what a pregnant woman encounters in her daily life – the air she breathes, the food and drink she consumes, the chemicals she’s exposed to, even the emotions she feels – are shared with her fetus. It incorporates these into its own body, making them part of its flesh and blood.

Research on fetal origins, also called the developmental origins of health and disease, is prompting revolutionary shifts in thinking about where human qualities come from and when they develop.

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Two decades ago, a British doctor named David Barker noticed an odd . pattern on a map: The poorest regions  of England and Wales had the highest rates of heart disease. But heart disease was supposed to be due to a sedentary lifestyle and rich food?
After comparing the health of 15,000 adults with their birth weights, he discovered an unexpected link between small birth size, often an indication of poor prenatal nutrition, and heart disease in middle age.

Dr Barker theorized that when a fetus does not get enough nutrition, it diverts nutrients to the brain, while skimping on other parts of its body. This shows up in later life as a weaker heart.

When he presented his findings to colleagues, he was mocked. “Heart disease was supposed to be all about
genetics or adult lifestyle,” says Dr Barker, now 72, and a professor at the University of Southampton in  England and at Oregon Health and Science University. “People scoffed at the idea that it could have anything to do with intrauterine experience.”
For years, the idea was just known as the Barker hypothesis. But in time, it began to win converts. Dr Janet Rich-Edwards, an epidemiologist at Brigham and Women’s Hospital in Boston analysed findings from the Nurses’ Health Study, a long-running investigation of more than 120,000 nurses in the US.

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The good news is that fetal researchers are also finding out that life in the womb can make things go better for your child in later life.

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Take your weight. Two studies by researchers at Harvard Medical School suggest your mother’s weight affects  yours. One study found that the more weight a woman gains during pregnancy, the more likely her child is to be overweight by age three.

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“The bodies of the children conceived after their mothers had weight-loss surgery process fats and carbohydrates in a healthier way than the bodies of their brothers and sisters  who were conceived at a time when their mothers were still overweight,” says John Kral, a professor of surgery and medicine and a co-author of both papers.

“It may be the intrauterine or womb environment is more important than genes or shared eating habits in passing on a tendency to be obese,” says Professor Kral. If that’s so, helping women maintain a healthy weight during pregnancy may be the best hope for stopping obesity before it starts.

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How does air pollution affect a baby in the womb? More than 30 years ago, [Upstream Contributor] Dr. Frederica Perera, the director of the Center for Children’s Environmental Health at Columbia University, was researching air pollution and cancer in adults. “I was looking for control subjects to compare to adults. I wanted individuals completely untouched by pollution,” she says.

She decided to use babies just out of the womb as her controls. So she sent samples of umbilical-cord blood and placental tissue to a laboratory to be analysed. When she got the results back, “I was shocked. These samples already had evidence of contamination.”

More.

From Greenwire:

Tall smokestacks are one reason that emissions from coal-fired power plants are blown across state lines, making it more difficult for downwind states to clean up their air, a new Government Accountability Office study found.

Nationwide, there are now 284 smokestacks in operation that are more than 500 feet tall, the report (pdf) says. About 35 percent of those are in five states along the Ohio River Valley — Ohio, Kentucky, Indiana, Illinois and Pennsylvania.

Power companies build tall stacks to avoid causing air quality problems in the area around coal plants. But the states along the I-95 corridor in the Northeast blame tall smokestacks for their struggles to meet federal air quality goals, claiming that the stacks feed into fast air currents that carry soot- and smog-forming emissions for hundreds of miles.

GAO found that many older coal plants have tall smokestacks and no modern pollution controls. Fifty-six percent of the boilers attached to tall stacks lack scrubbers to control sulfur dioxide (SO2), and 63 percent do not have controls to trap emissions of nitrogen oxides (NOx).

“Stack height is one of several factors that contribute to the interstate transport of air pollution,” the report says. “While the use of pollution controls has increased in recent years at coal power plants, several boilers connected to tall stacks remain uncontrolled.”

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From Discovery Magazine:

“There is no place called away.” It is a statement worthy of 
Gertrude Stein, but University of Washington atmospheric chemist Dan Jaffe says it with conviction: None of the contamination we pump into the air just disappears. It might get diluted, blended, or chemically transformed, but it has to go somewhere. And when it comes to pollutants produced by the booming economies of East Asia, that somewhere often means right here, the mainland of the United States.

Jaffe and a new breed of global air detectives are delivering a sobering message to policy makers everywhere: Carbon dioxide, the predominant driver of global warming, is not the only industrial by-product whose effects can be felt around the world. Prevailing winds across the Pacific are pushing thousands of tons of other contaminants—including mercury, sulfates, ozone, black carbon, and desert dust—over the ocean each year. Some of this atmospheric junk settles into the cold waters of the North Pacific, but much of it eventually merges 
with the global air pollution pool that circumnavigates the planet.

These contaminants are implicated in a long list of health problems, including neurodegenerative disease, cancer, emphysema, and perhaps even pandemics like avian flu. And when wind and weather conditions are right, they reach North America within days. Dust, ozone, and carbon can accumulate in valleys and basins, and mercury can be pulled to earth through atmospheric sinks that deposit it across large swaths of land.

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CleanAirBoard:

“In healthy children, lungs grow as the body develops, but the greatest growth rate is during puberty. From ages 10-14, healthy children see their lungs grow by about 12% each year. By the late teens or early twenties, lungs have essentially stopped growing. The Children’s Health Study shows that during the crucial puberty years, the lungs of a child exposed to high levels of pollution will grow 10% less each year. Over a period of four years, that is a significant deficit in lung function compared with kids growing up in low-pollution neighborhoods.”

Air pollution from diesel vehicles can affect everyone, especially children. Exposure to the toxic particles of diesel exhaust has been linked to cancer, asthma, and other diseases and conditions.

The clip discusses the findings of the Children’s Health Study, which was begun in 1992. The study was conducted by a team of scientists at the University of Southern California and funded by the California Air Resources Board. Scientists looked at 5,500 children from 12 communities in Southern California with differing types and levels of air pollution. The scientists followed children from each of these communities and then compared their respiratory health with the pollution levels in their communities.

The full-length video can be viewed below:

From documentary website:

Can air pollution cause long-lasting effects on children’s respiratory health? In 1992, the California Air Resources Board funded a study to try to answer questions on the long-term health effects of air pollution on children. The video describes the results of the Children’s Health Study, which was conducted by a team of scientists at the University of Southern California. Scientists looked at 5,500 children from 12 communities in Southern California with differing types and levels of air pollution. The scientists followed children from each of these communities and then compared their respiratory health with the pollution levels in their communities.

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