This word appeared on today's NHK news. It was not used alone, but came with a unique combination, 光化学(こうかがく)スモッグ. It is a very new word to me, and dictionaries tell me that this a translation to the term "photochemical smog", a type of pollution reported from some 60 years ago, and now became to occur in Japan. Obviously it is a new environmental challenge to people today, and it may have to involve a great effort for international cooperation to overcome it in the future.
Come to the language, this is certainly a easy term to people who understand English. It is such a short word, and the pronunciations both are very similar. However, we certainly can not expect that all Japanese natives have such knowledge. As for the concept of smog, we have wonderful expressions in Japanese, including 霧(きり) or 煙霧(えんむ). What is the point to introduce a new term here to confuse us?