VOA常速英语:空气污染导致儿童哮喘病例激增

We already know that traffic pollution is a big contributor to climate change, but new research suggests, it’s also a huge driver of health problems around the world. Recent estimates show that air pollution is actually the leading environmental health risk factor globally more than any other environmental cause of disease. According to the World Health Organization, air pollution causes an estimated 3.7 million premature deaths every year, but a new study from George Washington University in Washington DC points to a specific pollutant, nitrogen dioxide NO2, from car emissions as the leading cause of childhood asthma in many cities around the world. Nitrogen dioxide pollution has a really important impact on the number of children worldwide that are being diagnosed with asthma, and in fact the largest impacts were seen in cities where up to almost about 50 percent of new asthma cases among children, in some cities worldwide, were attributable to nitrogen dioxide pollution. And a really troubling element of the research, the cities where all this asthma is happening have levels of NO2 that are within limits considered safe by the World Health Organization.

One of the most surprising findings for us was that actually over 90 percent of annually pediatric asthma incidents occurred in areas that already met the World Health Organization guideline for annual average nitrogen dioxide pollution of 21 parts per billion. It’s not much of a surprise that most of the cities with the highest levels of NO2 pollution are in three countries, China, India and the United States. The solution these researchers say is to continue the fight against climate warming greenhouse gases because the two problems are so closely related. One of the things that we found in our study was that cities that had higher nitrogen dioxide levels also had higher greenhouse gases. And so one thing that can be done would be to avoid burning fossil fuels, and reduce it in any way we can. The researchers say they hope to do more studies to understand which specific chemicals in NO2 pollution trigger asthma, so they can help target those specific sources of emissions.
Kevin Enochs, VOA News.