China emits more sulfur dioxide than any other country in the world. All this contributes to the 'Asian Brown Cloud” which covers an area as large as Australia, obscuring the sun in some polluted Asian cities
Air pollution from China, India and several other Asian countries has wafted across the Pacific Ocean over the past 25 years, increasing levels of smog in the western US according to recent research. 1
Smog, also know as ground level ozone, is harmful to human health because it can exacerbate asthma attacks and cause difficulty breathing. It also harms sensitive trees and crops.
Since 2000 smog forming emissions have decreased by approximately 50 percent in the US due to Clean Act Air enforcement, pollution controls on large emitters and regulations on cars and trucks.
