November 30, 2004
[This is the print version of story http://www.abc.net.au/news/newsitems/200411/s1254510.htm]
A leading research body says tiny air-borne particles released by burning fossil fuels are reducing the average human life span across Europe and North America by eight months.
Studies showed that inhaled particles are a major cause of heart attacks, one of the world's biggest killers, a scientist from an Austrian-based research body said.
"We always knew that they had an effect on the respiratory system, but now we know that they spark cardiovascular disease by inflaming the heart membranes," said Markus Amann of the International Institute for Applied Systems Analysis (IAASA).
Power stations, road traffic, steel and cement plants and even wood-burning in country areas contribute to the build-up of the particles, he said.
Mr. Amann was speaking in advance of a conference in Geneva of the UN's Economic Commission for Europe (ECE), which is expected to set up an expert team to look at the problem.
The conference also marks the 25th anniversary of a pact on reducing cross-border air pollution, which has helped remove relatively heavy pollutants like sulfur from the atmosphere.
The fossil fuel particles that cause heart attacks, however, are light and can travel 2,000 to 3,000 kilometers on air currents.
Mr. Amann's institute is working with the ECE and the World Health Organization (WHO) to analyze the results of studies across North America, Europe and former Soviet Central Asia on the effects of the particles.
"It is a continental problem on a global scale and it can only be tackled through international cooperation," he said.
December 17, 2003
A study of the long-term effects of air pollution has given scientists reason to believe that it poses a greater risk of death from heart disease than from respiratory ailments.
"We might be able to reduce the underlying processes of some cardiovascular disease just by reducing the exposure to air pollutants. And possibly, there may be ways to mitigate the impacts of air pollution, such as anti-inflammatory medications or other interventions."
The study is published in the latest rapid access issue of Circulation: Journal of the American Heart Association.
The research, which used data on more than half a million people, also poses a theory on the mechanisms responsible for pollution- related heart deaths
— increased inflammation and nervous system changes that affect heart rhythm.The researchers found that about 45 percent of all deaths in the study population were due to cardiovascular diseases — including heart attacks, heart failure and cardiac arrest. Respiratory disease accounted for only 8.2 percent of the deaths.
They also found that air pollution conferred additional risk for smokers as well as nonsmokers.
In a sub-analysis, they found that former smokers had a 26 percent greater risk of death due to cardiovascular diseases and diabetes compared to never smokers. Current smokers had a 94 percent higher risk of death.
"There is no question that active cigarette smoking is a much, much larger risk factor than air pollution," said Pope, an expert in the economic effects of disease. "We don't know precisely how the two relate, but there is some evidence in our study that the mechanisms are similar or complementary."
06/11/2001
High levels of air pollution can trigger heart attacks in at-risk people exposed for even a short time, a study has found.
Researchers who interviewed 772 Boston-area patients about four days after their attacks found that the onset of symptoms correlated with times of high daily air pollution.
Tiny, invisible particles long have been thought to cause long-term cardiovascular diseases. The new study is the first to examine short-term effects on the heart, said senior author Dr. Murray Mittleman, director of cardiovascular epidemiology at Boston’s Beth Israel Deaconess Medical Center.
The study of 489 men and 283 women, conducted from January 1995 to May 1996, defined at-risk people as obese, inactive or those with a history of heart problems.
The results appear in Tuesday’s edition of Circulation, a journal of the American Heart Association.
The pollution particles are called PM-2.5, for particulate matter less than 2.5 micrometers in diameter. They’re emitted by cars, power plants and industry, as well as fireplaces and wood-burning stoves.
Studies in the past five years have linked deaths and hospital admissions to a spike in PM-2.5 levels. In the study, risk for heart attack peaked two hours and 24 hours after patients were exposed to increased levels of the particles.
After two hours, risk increased 48% in the hours when pollution was the worst, compared to the best hours; after 24 hours, risk increased 62%.
The study also examined health risks caused by ozone, a chief ingredient of smog that’s created when air pollutants mix. Ozone has been linked to lung and breathing problems, but researchers in this study found no data linking it to heart attacks, Mittleman said.
The study did not address how the particles trigger heart attacks. Other studies have shown that the particles, small enough to bypass the body’s defenses and get into the lungs and other tissue, cause inflammation and blood clotting. These symptoms may contribute to heart attacks by blocking flow of blood through the heart, some researchers say.
Still other studies have shown that the particles may create electrical reactions that affect the nervous system.
PM-25 particles are light enough to travel long distances and infest air that’s typically clean. Air conditioning systems and high-efficiency air filters help to remove PM-25 particles from indoor air.
"The best advice is to avoid outdoor activity on hot, hazy days", said study co-author Douglas Dockery, professor of environmental epidemiology at Harvard.
Researchers noted that Boston does not have excessive pollution and meets federal air quality standards, so the risk could be even worse in high-pollution cities such as Houston and Los Angeles.
The Environmental Protection Agency’s air quality standards, last updated in 1997, have been challenged in court in part because no one has pinpointed why pollution particles pose a health risk.
The study could be used to encourage the EPA to consider stricter air standards, said Dr. Jonathan Samet, chairman of the department of epidemiology at Johns Hopkins University, who was not involved in the study.
June 3, 2004
By Reuters
WASHINGTON — Air pollution causes heart disease, the American Heart Association said this week. While pollution does not cause as many heart attacks as high blood pressure, for example, it is a serious risk factor, the group said in a statement.
"This is a serious public health problem due to the enormous number of people affected and because exposure to air pollution occurs over an entire lifetime," said Dr. Robert Brook of the University of Michigan in Ann Arbor, who helped write the statement.
Writing in the Association's journal Circulation, Brook and colleagues said this was the first firm conclusion from the group about the long-term effects of chronic exposure to pollution.
Their statement adds authority to a collection of findings that some groups have disputed. They reviewed as many published studies as they could find on links between heart disease and pollution.
Particulate matter pollution (soot) is especially dangerous, they concluded. They also reaffirmed that secondhand smoke causes heart disease.
"A recent report from the American Cancer Society study cohort found that long-term exposure to fine particulate air pollution at levels that occur in North America increased the risk for cardiovascular mortality," Brook said.
Traffic is one of the worst sources, they found. An eight-year study of 5,000 adults showed people who lived near a major road were more likely to die of a cardiovascular problem.
More study was needed to understand how, exactly, pollution caused heart disease, the researchers said.
"We hope that these conclusions will provide further support to the importance of the present-day air quality standards," Brook said.
Source: Reuters