The Effects of Pollution on Health

Air pollution, even at levels generally considered safe by the authorities, the risk of stroke by 34 percent, according to a report in the Beth Israel Deaconess Medical Center (USA). In addition, according to another prospective investigation, conducted by a team from the Medical Center Rush University (USA), chronic exposure to contaminated air particles may accelerate cognitive decline in older adults.

The two studies, published in Archives of Internal Medicine confirms something we already knew, as is the negative impact of air pollution on human health. In Spain, it is estimated that over 80% of Spanish an air worse than the rates of health protection recommended by the World Health Organization (WHO). The consequences of this pollution will result in 16,000 premature deaths a year in Spain. According to the European Environment Agency (EEA), air pollution can reduce the life expectancy of Europeans up to three years.

In the first study we have analyzed the relationship between risk of stroke or stroke and exposure to air pollution on over 1,700 people who had suffered a stroke. The results showed that exposure to air pollution was associated with a significantly increased risk of ischemic stroke when the air quality index of the Environmental Protection Agency (EPA, for its acronym in English) was yellow instead of green. (The Air Quality Index is a simple scale based on a color code that describes the air quality. The range is green, meaning good, to brown, which means air quality conditions dangerous) .

Researchers have focused on PM2.5 particles, which come from a variety of sources (power plants, factories, trucks and cars and burning wood). Are easily absorbed through the lungs and previously had been associated with an increased number of hospital visits for cardiovascular diseases such as heart attacks.

More than 1,700 patients

They analyzed the medical records of more than 1,700 patients admitted to hospital for treatment of stroke. In addition, were able to estimate when the first symptoms of stroke first occurred at the same time, pollution levels to which they had been exposed for nearly 90 percent of the homes of patients suffered a stroke. “We believe, ’says Gregory Wellenius, coordinator of the work, which this study is novel because it has very precise data, both exposure to air pollution as the diagnosis of stroke.”

The study has been able to calculate that the peak of pollution exposure occurs 12-14 hours before the stroke. That information, they say, may be useful to researchers who want to investigate the mechanisms by which PM2.5 cause a stroke.

The information is very detailed report, for example, shows that microscopic particles carbonaceous and nitrogen dioxide, two pollutants associated with traffic, are closely linked to the risk of stroke, suggesting that pollution from cars and trucks can be a serious health problem.

Researchers estimate that the reduction of PM2.5 particle pollution by 20% could have prevented 6,100 of the 184,000 hospitalizations for stroke in the northeast U.S. in 2007. In addition, they stress, with not forget that the study has been done in Boston, a city with relatively clean air, with PM2.5 levels lower than those observed in many other parts of the country and, yet, ” found that within these moderate levels of stroke risk is greater on days with more particles in the air. “