About 4 million children worldwide develop asthma each year because of nitrogen dioxide air pollution, according to a study published today by researchers at the George Washington University. The study estimates that 64 percent of these new cases of asthma occur in urban areas. The study is the first to quantify the worldwide burden of new pediatric(儿科的) asthma cases linked to traffic-related nitrogen dioxide by using a method that takes into account high exposures to this pollutant that occur near busy roads, said Susan C. Anenberg, PhD, the senior author of the study.
"Our findings suggest that millions of new cases of pediatric asthma could be prevented in cities around the world by reducing air pollution," said Anenberg. "Improving access to cleaner forms of transportation, like electrified public transport, cycling and walking, would not only bring down NO2 levels, but would also reduce asthma, enhance physical fitness, and cut greenhouse gas emissions. "
Asthma is a disease that makes it hard to breathe when the lung's airways are inflamed. An estimated 235 million people worldwide currently have asthma, which can cause wheezing as well as life-threatening attacks.
The World Health Organization calls air pollution "a major environmental risk to health" and has established Air Quality Guidelines for NO2 and other air pollutants. The researchers estimate that most children lived in areas below the current NO2 guideline. They also found that about 92 percent of the new pediatric asthma cases that were caused by NO2 occurred in areas that already meet the WHO guideline.
"That finding suggests that the WHO guideline for NO2 may need to be re-evaluated to make sure it is sufficiently protective of children's health," said Pattanun Achakulwisut, PhD, lead author of the paper.
Additional research must be done to more persuasively identify the factors leading to asthma within complex traffic emissions. This effort will help to improve the estimates of new asthma cases tied to traffic emissions.
Science can't explain the power of pets, but many studies have shown that the company of pets can help lower blood pressure(血压) and raise chances of recovering from a heart attack, reduce loneliness and spread all-round good cheer.
Any owner will tell you how much joy a pet brings. For some, an animal provides more comfort than a husband/wife. A 2002 study by Karen Allen of the State University of New York measured stress(紧张) levels and blood pressure in people—half of them pet owners—while they performed 5 minutes of mental arithmetic(心算) or held a hand in ice water. Subjects completed the tasks alone, with a husband/wife, a close friend or with a pet. People with pets did it best. Those tested with their animal friends had smaller change in blood pressure and returned most quickly to baseline heart rates. With pets in the room, people also made fewer math mistakes than when doing in front of other companions. It seems people feel more released (放松) around pets, says Allen, who thinks it may be because pets don't judge.
A study reported last fall suggests that having a pet dog not only raises your spirits but may also have an effect on your eating habits. Researchers at Northwestern Memorial Hospital spent a year studying 36 fat people and their equally fat dogs who were put on diet-and-exercise programs; a separate group of 56 people without pets were put on a diet program. On average, people lost about 11 pounds, or 5% of their body weight. Their dogs did even better, losing an average of 12 pounds, more than 15% of their body weight. Dog owners didn't lose any more weight than those without dogs but, say researchers, got more exercise overall—mostly with their dogs—and found it worth doing.
