As traffic and other sources add more pollutants to the air, the smog gets worse. Ironically, smog is often more severe farther away from the sources of pollution, because the chemical reactions that cause smog take place in the atmosphere while pollutants are drifting on the wind. Smog: Frequently Asked Questions.
There are two major airports if you are flying into the Big Island, Kona International Airport [1] and Hilo International Airport [2]. There are a few non-stop flights from the mainland, mostly from California and Seattle, but it is more common to arrive via Honolulu or Kahului.
(Denver, Colorado - CO, USA) 1  Standing on an enormous site measuring in at more than 50 square miles / 130 square kilometres, Denver International Airport (DEN) is the biggest airport in the whole of the USA and is served by many domestic and international airlines, which in total number just over 20 different passenger airlines.