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Researchers have known since the 1970s that breathing in dirty air can be bad for your heart and lungs. Over the past decade, however, they have started to understand just how bad it is for your brain, too. Evidence shows air pollution has a negative impact on cognitive abilities for children and adults, and may even contribute to depression.

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What is Air Pollution?

There wasn’t much known about the chemical nature of air pollution, so in the late 1940s, U.S. scientists started developing air pollution monitoring devices to see what was in our air. Experts started to understand what we were breathing in and this research began to lay the groundwork for the U.S. government to establish the Clean Air Act in 1970. The federal program was put into place to monitor and control air pollution, as well as research techniques and come up with solutions and recommendations to combat it.

Air pollution occurs when particles enter the air that are bad for human, animal, and plant health. Much of it is particulate matter (PM) or particle pollution which is a mix of solid particles and liquid droplets in the air. PM is made up of hundreds of different sized chemicals and is emitted from things like power and manufacturing plants, vehicles, construction sites, fires, and smokestacks. Things like dirt, dust, smoke, or soot are large and dark enough that we can see them. Other things that contribute to particulate matter are so small you can only see them with a microscope.

Since particulate matter is small, it’s easy to inhale. The smaller the particle size, the deeper it goes into our bodies and the bigger the problems it can cause. The larger pieces may stay inside our nostrils, while fine particulate matter may end up deep in our lungs or bloodstream or travel through the olfactory nerve into our brains. And for scientists, fine particulate matter is of greater concern. They have realized it can cause serious heart and lung problems and increase a person’s risk of early death. But now they’re also starting to realize that it affects our cognitive ability.

How Does Air Pollution Affect Our Brains?

Over the past decade, more attention has been given to the relationship between air pollution and our brains. And you don’t have to be exposed to it for long periods of time for it to have an effect on your brain’s performance.

Scientists aren’t sure why or how air pollution affects our cognitive ability; they just know there’s a link. The biggest issue may be with heavy metals. When particles from metal reach your brain, it mistakes them for a pathogen and releases chemicals to kill them. The chemicals can build up and cause inflammation. Chronic inflammation in the brain is a factor in killing cells in the central nervous system. It’s also a factor in the development of dementia and Alzheimer’s Disease.

In the past decade or so, several studies have been done on the connection and the effect. One such study showed older women who had been exposed to high levels of fine particulate matter had greater cognitive decline than other women their age. Another study on men showed a decline in cognitive abilities for those who had a higher exposure to black carbon which is produced by diesel exhaust. And a separate group of researchers who exposed mice to fine particulate matter five times a week, eight hours a day to mimic large city pollution found the rodents had a harder time finding their way out of a maze. It also changed the brain structure of the animals.

How Does Air Pollution Affect Our Children and Grandchildren?

Poor air quality can also have a harmful effect on our children and grandchildren. Children breathe in more air per unit of body weight than adults. Add that to the fact their immune systems and lungs are still growing and it makes them prime candidates to be negatively impacted by dirty air. It’s been linked to asthma and other respiratory problems in children. Now, there’s growing evidence it can cause cognitive issues, as well. 

In 2008, researchers released the results of a study that was conducted on more than 200 Boston children. They were followed from birth to around ten years of age. The study showed the children who were exposed to higher levels of black carbon scored worse on memory tests and verbal and non-verbal IQ tests.

Researchers in New York found that children exposed to high levels of urban air pollutants had more attention problems, as well as symptoms of depression and anxiety.

What is Being Done to Combat Air Pollution?

Since the 1970s, U.S. lawmakers have taken air pollution more seriously. The Clean Air Act of 1970 began the federal government’s efforts to reduce and control air pollution in the United States. The legislation allowed federal and state authorities to regulate and determine safe limits for six major air pollutants. Every five years, the Environmental Protection Agency (EPA) reviews the standards for particulate matter to determine if they should be changed based on new scientific data.

Work to reduce carbon monoxide, vehicle emissions, fossil fuel use, and particulate matter have all resulted in healthier air in America. The federal government has partnered with large corporations to reduce air pollution and create technology that helps combat it. But air pollution is believed to be the cause of tens of thousands of deaths in the U.S. every year, so there’s still work to do.

What Can I Do About Air Pollution?

Even though air pollution is a global problem that we must address at the highest levels of government, there are still things you can do every day to reduce your exposure.

Check the Air Quality Where You Live

The government has a website and app called Air Now. You can download it to your smartphone and check the air quality for your zip code every day. If it’s out of normal range, then you will want to stay indoors as much as possible to avoid exposure.

Get Your Exercise but Not in High Traffic Areas

If you enjoy walking or running outside, try avoiding paths that have a lot of traffic. Or at least exercise at times of day when traffic isn’t as heavy. It will cut down on your exposure to vehicle emissions.

Consider Going Electric

Many mowers, blowers, weed trimmers, and cars run on electricity now. Using them will cut down on emissions you inhale from gas-powered models.

Invest in an Air Purifier

The quality of the air inside your home is something you can control. Air purifiers will pull the harmful particles out of the air and force cleaner, purer air back out. Most air purifiers run with a HEPA filter which can eliminate up to 99.97% of the smallest pollutants floating around inside.

Avoid Smoke

If you’re a smoker, then consider quitting – for your health and the health of everyone around you. The contaminants in cigarette and cigar smoke are bad for you. If you aren’t a smoker, then don’t let anyone smoke in your home or car, and don’t frequent bars that permit it.

Limit Outdoor Fires

Outdoor fires can certainly be nice and cozy, but they also send pollution into the air. If you do have an outdoor fire, keep it small and burn only dry wood.

Get Involved

Plenty of cities and states have their own clean air initiatives and they can always use volunteers. Find a group that interests you and help out. When more people work together, greater change happens.


Dozens of studies have been done on air pollution and the problems it can cause for our heart and lungs, and now scientists are beginning to focus on how it impacts our brain function. More research will need to be done, but there seems to be a fairly strong correlation between exposure to dirty air and a decline in cognitive function. It’s important to protect yourself by avoiding heavy pollution areas when you can and making personal choices at home that will improve the quality of the air you breathe.

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