Outdoor carbon monoxide: risk to millions.In the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. alone, an estimated 3 million individuals--most of them over the age of 65--suffer from congestive heart failure congestive heart failure, inability of the heart to expel sufficient blood to keep pace with the metabolic demands of the body. In the healthy individual the heart can tolerate large increases of workload for a considerable length of time. , the inability of the heart to pump out all of the blood that returns to it. A new study now indicates that even federally permissible levels of carbon monoxide carbon monoxide, chemical compound, CO, a colorless, odorless, tasteless, extremely poisonous gas that is less dense than air under ordinary conditions. It is very slightly soluble in water and burns in air with a characteristic blue flame, producing carbon dioxide; , a common air pollutant, can aggravate this life-threatening condition enough to send its victims to the hospital.
"It was really striking," says Robert D. Morris of the Medical College of Wisconsin in Milwaukee, who led the study. "In every city we looked at, there was an elevation in heart-failure admissions on days that carbon monoxide went up." Moreover, this effect appeared regardless of the extent to which the patients had also been exposed to other major gaseous pollutants--nitrogen dioxide, sulfur dioxide sulfur dioxide, chemical compound, SO2, a colorless gas with a pungent, suffocating odor. It is readily soluble in cold water, sparingly soluble in hot water, and soluble in alcohol, acetic acid, and sulfuric acid. , or even ozone.
Carbon monoxide reduces the blood's ability to carry oxygen. Previous studies have shown that high exposure to the pollutant for a short period lowers the exertion needed to trigger chest pain (angina) in susceptible individuals--the health impact upon which current federal limits are based. However, Morris' team found that the carbon monoxide concentrations linked to the increases in hospital admissions could be lower than those needed to bring on angina.
Morris and his colleagues obtained daily records of meteorological conditions and outdoor gaseous air pollutants in seven U.S. cities--Chicago, Detroit, Houston, Los Angeles, Milwaukee, New York New York, state, United States
New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of , and Philadelphia. They compared the information with 4 years of Medicare data on hospital admissions for heart failure in these cities. Only carbon monoxide readings correlated consistently with hospitalizations, they report in the October American Journal of Public Health The American Journal of Public Health (AJPH) is a peer reviewed monthly journal of the American Public Health Association (APHA). The Journal also regularly publishes authoritative editorials and commentaries and serves as a forum for the analysis of health policy. .
Approximately 11.6 million people live within the 73 U.S. areas that year after year exceed federal carbon monoxide limits (8 parts per million parts per million
mg/kg or ml/l; see ppm. for 9 hours or 35 ppm for 1 hour), notes Dave Ryan, an Environmental Protection Agency Environmental Protection Agency (EPA), independent agency of the U.S. government, with headquarters in Washington, D.C. It was established in 1970 to reduce and control air and water pollution, noise pollution, and radiation and to ensure the safe handling and spokesman. But the problem isn't limited to those areas, because "there appears [to be] no threshold for this effect," Morris notes. Even on days that fell well below EPA's limits, he says, his team charted a 20 to 40 percent increase in heart failure admissions for every 10 ppm increase in the gas.
Overall, between 2 and 11 percent of hospital admissions for congestive heart failure, depending on the city, could be traced to carbon monoxide. Those roughly 3,300 such incidents each year cost an estimated $33 million.
Nationally, the tally could run many times that, says Joel Schwartz of the Harvard School of Public Health The Harvard School of Public Health is (colloquially, HSPH) is one of the professional graduate schools of Harvard University. Located in Longwood Area of the Boston, Massachusetts neighborhood of Mission Hill, next to Harvard Medical School and Cambridge, Massachusetts, in Boston. While this constitutes a minor proportion of heart disease, it's not a minor environmental risk, he points out in an accompanying editorial. Hazardous waste Hazardous waste
Any solid, liquid, or gaseous waste materials that, if improperly managed or disposed of, may pose substantial hazards to human health and the environment. Every industrial country in the world has had problems with managing hazardous wastes. sites and toxic air pollutants that pose "much lower" risks are regulated, he notes.
"As the population ages," Morris adds, "the subset that is vulnerable [to carbon monoxide] will only increase."
Though outdoor carbon monoxide results almost exclusively from motor vehicles, these sources spew other toxic pollutants as well, including dust-sized particles. Recently, Schwartz and Morris reported data from Detroit indicating that these easily breathed particles may be responsible for some share of the city's hospital admissions for congestive heart failure (SN: 7/1/95, p.5). Again, Morris says, "this carbon monoxide effect tended to be independent of the other pollutants [fine particles]."
Morris concludes that any lessening of carbon monoxide pollution will show health benefits. To Schwartz, the new findings on congestive heart failure also suggest that "it is time to reevaluate the basis for regulating carbon monoxide."