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.
The largest airport in the world in terms of square footage is the King Fahd International Airport in Damman, Saudi Arabia. It covers 485 square miles! In terms of number of passengers, Hartsfield-Jackson International Airport in Atlanta, Georgia is the largest/busiest in the world. It served 92 million passengers in 2011 alone.