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

两者都是的关键成分，这是一直困扰洛杉矶的原因。

The infrared radiation emitted from a mammalian body has low quantum energy, which makes any photochemical effect on a pigment extremely unlikely.

哺乳动物身体发出的红外辐射有较低的量子能量，这使得对颜料产生任何效应的可能性极小。

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

车辆排放的和空气中的颗粒物影响着许多快速发展的城市，从墨西哥城和圣地亚哥到新德里和德黑兰。