Smog is a type of air pollution. Smog forms when sunlight reacts with chemicals in the atmosphere, creating a haze of tiny particles. These particles can cause health problems when inhaled, and they also make the air look hazy and dirty.
Smog is most common in big cities, where there are lots of cars and factories. But smog can form anywhere there are high levels of pollution in the air. This can happen after a forest fire, for example.
There are two main types of smog: ground-level ozone smog and particulate matter smog. Ground-level ozone smog forms when emissions from cars and other engines react with each other in the presence of sunlight. Particulate matter smog occurs when tiny particles suspended in the air mix together and form a haze. Both types of smog can be harmful to human health.
Ground-level ozone smog is especially harmful to people with asthma or other respiratory conditions. It can cause coughing, wheezing, shortness of breath, and chest pain. It can also worsen bronchitis, emphysema, heart disease, and other chronic respiratory diseases. People with these conditions should avoid exposure to ozone smog as much as possible. If you must be outdoors during an ozone episode, try to stay indoors as much as possible or wear a mask that covers your nose and mouth