Scientific Studies Support New Look at Air Quality Standards

EPA is right to revise small-particle pollution standards 

Published: Friday, June 29, 2012, 5:00 AM

By Tami Davis Biddle and Thomas Y. Au

When we look back on photos, film and other imagery from the mid-20th century, we are often struck by the prevalence of cigarettes. Americans smoked; many smoked heavily. Smoking cigarettes was not only considered acceptable, it was considered appealing, attractive and cool. Then we learned better.

Scientific studies began to pile up more and more evidence, from the 1960s through the 1980s, indicating that smoking was directly linked to all kinds of negative health outcomes, most notably cancer. Public information, including government-led campaigns, helped us see the light.

In the second decade of the 21st century a similar ground-swell of awareness is developing about the air around us. This groundswell, too, has developed gradually and is just now beginning to gain a head of steam. Once again it pertains directly to our health, and once again it pertains directly to the air we put into our bodies. This time, however, the focus is on air pollution and “fine particulate matter,” which is invisible and small enough to penetrate readily into human body tissue.

From the 1990s, scientific evidence has been piling up regarding the wide array of negative health effects of air pollution. And that evidence has pointed a particularly telling finger toward fine particulate matter, or PM 2.5 for short. It is well-established that exposure to air pollution increases the incidence of respiratory illness, including bronchitis and asthma.

Recent studies, including one run by the Columbia Center for Children’s Environmental Health, have drawn direct links as well between high levels of combustion-generated pollutants and high rates of infant mortality, low birth weight and cancer. In recent years, a direct link has been established between air pollution and cardiovascular illness. This link has been confirmed repeatedly in studies by scientists around the world. This problem is of concern in central Pennsylvania, where small-particle pollution is high.

If all this wasn’t enough to give us pause, researchers have begun to find strong linkages between PM 2.5 and two other dreaded health problems: stroke and cognitive degeneration. A recent study run by Gregory Wellenius of the Brown University Center for Environmental Health and Technology revealed that on days when concentrations of traffic pollutants go up, so, too, does the risk of stroke.

The increased stroke risk was highest within 12 to 14 hours of exposure to PM 2.5 and was most strongly associated with traffic-related pollution. Regarding the latter finding, the authors noted that “Experimental studies in humans and animals have shown that exposure to concentrated ambient PM 2.5 can induce increases in blood pressure and heart rate and reductions in heart rate variability within this time frame.”

What is perhaps most striking about this study is that PM 2.5 exposure increases the risk of ischemic stroke at levels below those currently considered safe under U.S. regulations. This observation prompted Dr. Rajiv Bhatia of the San Francisco Department of Public Health to suggest that ambient air quality standards should be reviewed. Bhatia argued that improved human control of PM 2.5 is “technically feasible, but will require increased efforts to assess exposure at the community level, more stringent and creative regulatory initiatives, and political support.”

In a study with equally daunting ramifications, Jennifer Weuve of the Rush University Medical Center in Chicago found women with higher levels of long-term exposure to course and fine particulate matter (PM 2.5) had significantly faster declines in cognition than those with less exposure to pollutants. Weuve and her colleagues found evidence that fine particulate can penetrate the brain through the nasal passages. Her study followed 19,409 women in the U.S. between ages 70 and 81 for about a decade, looking at cognitive changes every two years.

All of these studies have significant ramifications for national health policy and regulatory policy in the United States, suggesting stronger efforts to control fine-particle pollution might be needed to protect the general population. These studies should be in the forefront of the public debate as the Environmental Protection Agency considers whether to raise the standards for fine particulate.

Tami Davis Biddle and Thomas Y. Au are members of the Clean Air Board of central Pennsylvania. 

Nano Pollution and Health (Video)

Nano Pollution and Health

February 21, 2008 — Scientists find that air pollution is even worse for you than previously thought. As this ScienCentral News video explains, new research shows how tiny particles from vehicle emissions can cause heart disease and other problems.

Sponsored by the National Science Foundation.

EPA Standards and Better Health: Tami Biddle, CAB

January 24, 2010 – EPA Standards and Better Health

By Tami Biddle, CAB Executive Board Member

Earlier this month the Environmental Protection Agency proposed regulations that would further tighten restrictions on smog. A composite of the word “smoke” and “fog,” the term smog has been used for years to describe the polluted air that often hangs over congested areas with high levels of traffic and industry. Smog contains several substances detrimental to human health. These include, in particular, ozone, nitrogen dioxide, and fine particulate matter known as PM 2.5. In recent decades our understanding of the very serious health risks of air pollution has grown more sophisticated and more detailed as scientific studies documenting these risks have been undertaken around the world.

A study by the World Health Organization, published in the summer of 2004, concluded that air pollution increased “the risk of cardiopulmonary disease and a reduction in life expectancy of a year or more for people living in European cities.” The researchers indicated that these effects could occur “at very low concentrations that were previously considered safe.” Overall, they stated that “the evidence is sufficient to strongly recommend further policy action to reduce levels of air pollutants, including particulates, nitrogen dioxide and ozone.” Recent research has continued to bear out these alarming findings.

A study just published in the American Journal of Respiratory and Critical Care Medicine (AJRCCM), for instance, found that ambient levels of nitrogen dioxide and fine particulate matter, PM 2.5, “were independently associated with pneumonia hospitalization in older adults.” Two other recent AJRCCM articles, one based on a study in the Czech Republic and one based on a study in Mexico City, found that young children were especially susceptible to air pollution-related illness.

A study published in the December 2009 issue of the journal, Chest , is of particular concern to those who have asthma. The researchers found that higher levels of certain air pollutants, in particular ozone and nitrogen dioxide, reduced the effectiveness of inhalers used by asthma patients.

In recent studies P.M. 2.5, which is small enough to embed itself deep into body tissues, has been particularly linked to heart disease. A 2009 study published in the journal Environmental Health Perspectives, titled “The Effect of Fine and Coarse Particulate Air Pollution on Mortality: A National Analysis,” concluded that there was “an increased risk of mortality for all and specific causes associated with PM 2.5.” Findings like these are the reason why the Clean Air Board of Central PA is so concerned about PM 2.5 levels in our region.

Overall, the evidence is clear – and worrisome. In the same way that scientists warned us, over time, of the profound hazards of cigarette smoking, they are now warning us about the profound hazards of air pollution. In the face of such evidence, it is time for our regulatory agencies and legislators to act. The recent proposed tightening of smog regulations by the EPA is fully warranted, and reveals a government agency functioning as it should. The cost of implementing the new standards will be more than made up for by increases in worker productivity, and reductions in existing health care costs. The EPA’s action should be welcomed by citizens of Central Pennsylvania, where air quality is among the poorest in the nation. It is now time for Pennsylvanians to do their part, helping the EPA to bring cleaner air to our region. A failure to accept the implications of this evidence would be a failure to accept responsibility for our future, and for the health of our children and our elderly in particular.

Resources and References:

B. Neupane, et al, “Long Term Exposure to Ambient Air Pollution and Risk of Hospitalization with Community-acquired Pneumonia in Older Adults,” American Journal of Respiratory and Critical Care Medicine , 181, 47-53, 2010

I. Hertz-Picciotto, et al, “Early Childhood Lower Respiratory Illness and Air Pollution,” AJRCCM , 115 (10), 1510-1518, 2007

R. Rohas-Martinez, “Lung Function Growth in Children with Long-Term Exposure to Air

Pollutants in Mexico City,” AJRCCM 176, 377-384, 2007

http://ajrccm.atsjournals.org

Environmental Health Perspectives : http :// ehp . niehs . nih . gov 07/24/02 04:21 L.

Hernandez-Cadena, F. Holguin, et al, “Increased Levels of Outdoor Air Pollutants Are Associated With Reduced Bronchodilation in Children With Asthma,” Chest , December 2009 136 : 1529 – 3

World Health Organization Report, “Health Aspects of Air Pollution,” June 2004 http://www.euro.who.int/ document/E83080.pdf

Zanobetti A, Schwartz J, “The Effect of Fine and Coarse Particulate Air Pollution on Mortality: A National Analysis ” Environmental Health Perspectives 117:898-903. 2009

“National Cost of Air Pollution” (ICAP) study released by the Canadian Medical Association, summarized by Medical News Today in an article called “Illness Cost of Air Pollution Underscores Need for Lung Health Action Plan: The Lung Association,” 14 August 2008.

http://medicalnewstoday.com

Particulate Air Pollution Affects Heart, Research Finds: Science Daily

Particulate Air Pollution Affects Heart, Research Finds

ScienceDaily (May 20, 2010) — Breathing polluted air increases stress on the heart’s regulation capacity, up to six hours after inhalation of combustion-related small particles called PM2.5, according to Penn State College of Medicine researchers.

Stress on the heart from exposure to high levels of PM2.5 may contribute to cardiovascular disease, said Duanping Liao, professor of public health sciences.

The body’s ability to properly regulate heartbeat so the heart can pump the appropriate amounts of blood into the circulation system relies on the stability of the heart’s electrical activity, called electrophysiology.

“Air pollution is associated with cardiopulmonary mortality and morbidity, and it is generally accepted that impaired heart electrophysiology is one of the underlying mechanisms,” said Fan He, master’s program graduate, Department of Public Health Sciences, Penn State College of Medicine. “This impairment is exhibited through fluctuations in the heart rate from beat to beat over an established period of time, known as heart rate variability. It is also exhibited through a longer period for the electric activity to return to the baseline, known as ventricular repolarization.

“The time course, how long it would take from exposure to cardiac response, has not been systematically investigated,” said He. “We conducted this study to investigate the relationship between particle matter and heart electrophysiology impairment, especially the time course.”

The researchers published their results in recent issues of the Journal of Exposure Science and Environmental Epidemiology and in Environmental Health Perspectives.

Liao’s team of researchers studied 106 people from central Pennsylvania, mostly in the Harrisburg metropolitan area. Nonsmokers over the age of 45 without severe cardiac problems wore air-quality and heart-rate monitors for 24 hours. The devices recorded data in one-minute intervals.

Results indicate that heart electrophysiology was affected up to six hours after elevated PM2.5 exposure. These adverse effects may trigger the onset of acute cardiac events and over time may result in increased risk of chronic heart disease.

PM2.5 refers to particles up to 2.5 micrometers in size. Their primary sources are diesel engine and coal combustion outdoors; and oil, gas or wood combustion for cooking and heating indoors. PM2.5 levels are regulated by the U.S. Environmental Protection Agency.

Restricting PM2.5: A Sure Way to Improve America’s Health: Tami Biddle, CAB

Restricting PM2.5: A Sure Way to Improve America’s Health (952 KB)

by Tami Biddle

Clean Air Board of Central Pennsylvania

October 2008

The Health Risks of Diesel Idling: Tami Biddle, Clean Air Board

The Health Risks of Diesel Idling (30 KB)

by Tami Biddle

Clean Air Board of Central Pennsylvania

October 2008

In recent years scientists have begun to understand a great deal about the effects of a type of air pollution referred to as “particulate matter.”  One type that is especially worrisome is called PM 2.5, meaning matter that is 2.5 micrometers or smaller in size.  This means, roughly, about one-thirtieth the size of a human hair.  The reason that PM 2.5 is dangerous is because the particles are small enough to penetrate into the deepest part of the lungs. And this, in turn, means that they are directly linked to asthma, bronchitis, and chronic respiratory illness.  Scientists have also linked PM 2.5 to low birth weight babies, heart disease, some cancers, and premature deaths in elderly people.

Children are more vulnerable to the health risks of PM 2.5 because their immune and respiratory systems are still developing. Also, children breathe up to 50 percent more air per pound of body weight than adults.  The breathing of fine particles by children is believed to cause both acute and chronic respiratory problems such as asthma.  Forty percent of all US asthma cases are in children, yet children make up only 25 percent of the US population.[1]

The sources of PM 2.5 include fuel combustion from automobiles, power plants, wood burning, and industrial processes.  But a major contributor to PM 2.5 levels is diesel powered vehicles such as trucks and buses. These fine particles are also formed in the atmosphere when gases such as sulfur dioxide, nitrogen oxides — all of which are also products of fuel combustion — are transformed in the air by chemical reactions.  Fine particles are attracted to water, thus contributing to acid rain.  Acid rain affects all things biological, and can have direct effects on human health.  For all these reasons, the Environmental Protection Agency (EPA) has taken an initiative to monitor and address fine particles in the atmosphere.

The seriousness of the heath risks posed by PM 2.5, and the special impact of particulate matter on children, has prompted many communities to start to address the problem in multiple ways.  One of the most important has been to encourage the limitation of idling by school buses.  Each year, over 21,000 school buses transport 1.5 million children to schools in Pennsylvania.[2] Restricting diesel idling would improve the health of Pennsylvania’s children, and the health of the drivers who transport them each day.


[1] Environmental Protection Agency   http://www.epa.gov/region4/sesd/pm25/p2.htm

[2] Clean Air Council   http://www.cleanair.org

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