The term smog was initially coined during the Fifties when it was used to explain a combination of smoke and fog experienced in London. Metropolitan cities located along the west coast of US were also experiencing a special type of pollution in air. What we tend to generally take as “smog" nowadays is nothing but a mixture of pollutants, primarily created of ground-level ozone. The ozone can be useful or hazardous depending on its location. The ozone located higher than the planet within the stratosphere protects human health and its surroundings. But ground-level ozone causes health problems such as choking, coughing, and stinging eyes related to smog. Smog happens when emissions from business, motorcars, incinerators, open burning and alternative sources accumulate below the compact atmospheric zone. There are two types of smog: summer (the smog initially experienced in America) and winter (the one initially noticed in London).