HIAW - What is Air Pollution? Lesson

What is Air Pollution

Pollution in the Air

When you think of air pollution what comes to mind?

Let’s take a deeper look into air pollution.

So What is Air Pollution?

Air pollution "is the introduction of particulates, biological molecules, or other harmful materials into Earth's atmosphere, causing disease, death to humans, damage to other living organisms such as food crops, or the natural or built environment.” 

Air pollution may come from anthropogenic (man made) or natural sources. Stratospheric ozone depletion due to air pollution has been recognized as a threat to human health as well as to the Earth's ecosystems. Indoor air pollution and urban air quality are listed as two of the world's worst toxic pollution problems causing the deaths of around 7 million people worldwide. An air pollutant is a substance, solid, liquid, or gas, in the air that can have adverse effects on humans and the ecosystem.

Primary or Secondary

	Primary pollutants are usually produced from a process, such as ash from a volcanic eruption, carbon monoxide gas from motor vehicle exhaust, or the sulfur dioxide released from factories.
	Secondary pollutants are not emitted directly but are formed in the air when primary pollutants react or interact. Ground level ozone is a prominent example of a secondary pollutant.

Some pollutants may be both primary and secondary: they are both emitted directly and formed from other primary pollutants.

History of Air Pollution

Air pollution started to be a problem when early people burned wood for heat and cooking fires in enclosed spaces such as caves and small tents or houses. But problems became more widespread as fossil fuels, such as coal, began to be burned during the Industrial Revolution.

Watch the video below to learn more.

Types of Pollution

As mentioned before, the two types of air pollutants are primary pollutants, which enter the atmosphere directly, and secondary pollutants, which form from a chemical reaction.

Use the image below to learn about these types of pollutants and where they come from. Click on each information circle you find in the image. 

Air Quality

People have euphemisms for smog; sometimes it's fog, sometimes it's haze. It's hard to know sometimes whether the air is full of something natural, like water vapor, or something man-made, like ozone. But in cities like Los Angeles the air is often being marred by air pollution and it is only getting worse. 

Scientist are studying how pollutants are getting into the air and passed on globally.

Watch the video below to learn more.

Terrible air pollution events in Pennsylvania (1948) and London, in which many people died, plus the recognition of the hazards of photochemical smog, led to the passage of the Clean Air Act in 1970 in the United States. The act now regulates 189 pollutants. The six most important pollutants regulated by the Act are ozone, particulate matter, sulfur dioxide, nitrogen dioxide, carbon monoxide, and the heavy metal lead. Other important regulated pollutants include benzene, perchloroethylene, methylene chloride, dioxin, asbestos, toluene, and metals such as cadmium, mercury, chromium, and lead compounds.

The Clean Air Act

What is the result of the Clean Air Act? The United States is much cleaner Visibility is better People are no longer incapacitated by industrial smog However, despite the Act, industry, power plants, and vehicles put 160 million tons of pollutants into the air each year. Some of this smog is invisible and some contributes to the orange or blue haze that affects many cities.

Air quality in a region is not just affected by the amount of pollutants released into the atmosphere in that location but by other geographical and atmospheric factors. Winds can move pollutants into or out of a region and a mountain range can trap pollutants on its leeward side. Inversions commonly trap pollutants within a cool air mass. If the inversion lasts long enough, pollution can reach dangerous levels.

Pollutants remain over a region until they are transported out of the area by wind, diluted by air blown in from another region, transformed into other compounds, or carried to the ground when mixed with rain or snow.

Look at this table; which city was the smoggiest in 2018?

What is Air Pollution Challenge

Before You Go, You Need To Know

The following key points are from this explore section of the lesson. You must know the following information before moving to the next lesson. This is just a summary of the key points.

IMAGES CREATED BY GAVS  OR OPEN SOURCE