Factories like this are a major source of air pollution. Click on image for full size (51 Kb) Copyright UCAR

Air pollution changes our planet’s climate, but not all types of air pollution have the same effect. There are many different types of air pollution. Some types cause global warming to speed up. Others cause global warming to slow down by creating a temporary cooling effect for a few days or weeks. Read on the learn more about the pollution that causes Earth to warm and the pollution that causes Earth to cool.

Some air pollutants cause more global warming

Air pollution includes greenhouse gases. One of these is carbon dioxide, a common part of the exhaust from cars and trucks. Greenhouse gases cause global warming by trapping heat from the Sun in the Earth’s atmosphere. Greenhouse gases are a natural part of Earth’s atmosphere, but in the last 150 years or so, the amount in our atmosphere has increased. The increase comes from car exhaust and pollutants released from smokestacks at factories and power plants. The increase in greenhouses gases is the cause of most of the global warming that happened over the past century. Scientists predict that much more warming will likely happen during the next century.

Some air pollutants slow down global warming

Cars, trucks, and smokestacks also release tiny particles into the atmosphere. These tiny particles are called aerosols. They can be made of different things such as mineral dust, sulfates, sea salt, or carbon. Some of these particles get into the atmosphere naturally. They are dust lifted into the atmosphere from deserts, from evaporating droplets from the ocean, released by the smoke from wildfires, and erupting volcanoes. But air pollution released by humans by burning of fossil fuels also adds them to the atmosphere. Aerosols have an impact on climate. While different types of aerosols act differently in the atmosphere, the overall effect of aerosols is cooling.

Greenhouse gases stay in the atmosphere for years and cause warming around the world. Computer models indicate that, worldwide, the tiny aerosols cause about half as much cooling as greenhouse gases cause warming.