You'd see a cloud of photochemical smog covering the planet.

你会看到一团学烟雾笼罩着地球。

Both industrial and photochemical smog combine manmade pollution with local weather and geography.

业烟雾和学烟雾都将人为污染与当地天气和地理因素结合在一起。

Both are key ingredients in photochemical smog, which is what had been plaguing LA.

两者都是学烟雾关键成分，这是一直困扰洛杉矶原因。

Photochemical smog is strongest in urban areas with calm winds and dry, warm, sunny weather.

学烟雾在市地区最强， 风平缓，天气干燥、温暖、阳明媚。

Secondary pollutants found in photochemical smog can damage and weaken crops and decrease yield, making them more susceptible to insects.

学烟雾中发现二次污染物会破坏和削弱农作物并降低产量，使它们更容易受到昆虫侵害。

Photochemical smog and airborne particles from vehicle emissions affect many rapidly developing cities, from Mexico City and Santiago to New Delhi and Tehran.

车辆排放学烟雾和空气中颗粒物影响着许多快速发展市，从墨西哥和圣地亚哥到新德里和德黑兰。

And while some ozone in the upper atmosphere helps shield us from ultraviolet rays, on the ground, this gas can form alongside secondary particles and create photochemical smog.

它们会发生反应，形成臭氧。虽然高层大气中臭氧能帮我们阻挡紫外线，在地面，这类气体可能会和衍生性粒子一起形成，产生学烟雾。

First, we must verify the detection of phosphine itself, and then later, we would have to confirm that this gas is coming from life and not from some unexpected geological or photochemical process.

首先，我们必须验证磷氢本身检测，然后我们必须确认这种气体来自生命，而不是来自一些意想不到地质或学过程。