野火烟雾加重美国空气污染

We start with a troubling new study out of Stanford University, where researchers found that wildfire smoke is undoing progress toward cleaner air across America.

我们从斯坦福大学一项令人不安的新研究开始报道。斯坦福大学研究人员发现，野火烟雾正在破坏全美在净化空气方面取得的进展。

Air pollution from wildfire smoke can spread for miles like this summer when smoke from Canada drifted into the U.S. turning skies in New York City, yellow.

野火烟雾造成的空气污染可以蔓延数英里，就像今年夏天来自加拿大的烟雾漂散到美国时一样，使纽约市的天空变成了黄色。

And wildfire smoke is a type of particle pollution or PM2.5.

野火烟雾是一种颗粒污染(PM2.5)。

Because the particulates are so tiny, they can sneak past our body's natural defenses and get into our system.

因为这些微粒物质非常微小，它们可以偷偷越过我们身体的自然防御系统，从而进入我们内部的身体系统。

If they get into your lungs and bloodstream, they could trigger asthma attacks or even heart attacks in some people.

如果它们进入身体的肺部和血液，可能会引发哮喘发作，甚至会导致有些人心脏病发作。

And long-term exposure can lead to deadly diseases, taking months or even years off of your life.

长期暴露在颗粒中会导致致命疾病，缩短几个月甚至几年的寿命。

PM2.5 had become less concentrated in recent decades thanks to air quality improvement measures.

由于采取了改善空气质量的措施，PM2.5的浓度在近几十年有所下降。

But this new study shows that progress has been slowed or even reversed in 35 states because of wildfire smoke.

但这项新研究表明，由于野火烟雾，35个州的空气质量改善进展放缓，甚至被逆转。

Here's cnn's Chief Medical Correspondent, Dr. Sanjay Gupta with more.

cnn首席医疗记者桑杰·古普塔博士将带来详细报道。

Look around you, take a breath. What do you notice?

环顾四周，深呼吸。你注意到了什么?

It's hard to imagine, but even air that looks and feels clean could still be harmful.

很难想象，不过，即使是看起来和摸起来干净的空气也可能是有害的。

Air pollution is when anything chemical, physical or biological changes the atmosphere.

当任何化学、物理或生物物质改变大气时，就产生了空气污染。

And the main culprit of air pollution has long been fossil fuels, but wildfires like the ones that we've been seeing a lot of lately are increasingly impacting our air quality.

空气污染的罪魁祸首一直是化石燃料，但像我们最近看到的很多野火正在越来越多地影响着我们的空气质量。

In fact, as things stand now, according to the World Health Organization, nearly all of us breathe air that is polluted.

事实上，根据世界卫生组织的数据，照目前情况看，我们几乎所有人都呼吸着被污染的空气。

What you might notice again, even if the air seems OK, our symptoms like eye, nose or throat irritation, wheezing, coughing, headaches, fatigue, dizziness.

你可能会再次注意到，即使空气看起来很好，但我们还会出现一些症状，如眼睛发炎、鼻炎或咽炎，还会出现气喘、咳嗽、头痛、疲劳、头晕的症状。

And one type of air pollution called particle pollution or PM2.5 can be especially dangerous.

一种被称为颗粒污染(PM2.5)的空气污染可能尤其危险。

And that's because of how tiny the particles are.

这是因为这些颗粒物质非常小。

These particles can be 1/20th, the width of a human hair, which means they can travel past your body's usual defenses.

这些颗粒物质的直径可能是人类头发宽度的1/20，这意味着它们可以越过身体通常的防御系统。

Now, I know you hear this and a lot of this might worry you, but there are also ways that you can protect yourself.

现在，我知道你听到了这些信息，其中很多信息可能会让你担心，但也有一些方法可以保护自己。

First of all, just like you might check the weather before you leave the house, you should also check your air quality.

首先，就像可能会在出门前查看天气一样，你也应该查看一下空气质量。