What Is PM 2.5?

Many recent science pieces and health articles mention PM 2.5. It’s also often mentioned in news coverage of wildfires or other pollution disasters. Scientists and experts say high levels of PM 2.5 can be very harmful to our  health. In this article, we’ll get into more detail on what PM 2.5 is, how it causes health problems, and what we can do to lower our exposure to it.

What Is PM 2.5?

PM 2.5 represents a category of specific pollutant, no larger than 2.5 microns. PM is an acronym for particulate matter. Health organizations put particulate matter into categories set by size, since different-sized particles have different impacts on our health. For example, particles smaller than 10 microns in size (PM 10) can cause health problems to the nose and eyes. Due to their relatively large size, the amount of those PM 10 particles that actually gets into the lungs is less, and therefore, not as dangerous dangerous for the lungs compared to smaller particles, such as PM 2.5.

PM 2.5 or smaller are thought of as hazardous for human health since they can make it through numerous human body’s defenses. The goal of nose hair, mucus, and similar remaining defenses is to stop small particles from getting deeper into the body. PM 2.5 particles are quite tiny though, so they’re able to reach our lungs, get to the alveoli, and eventually, enter the bloodstream.

PM 2.5 can consist of various kinds of particles and chemicals. What makes PM 2.5 particles stand out is that they can be partly liquid, unlike ‘normal’ dust particles that are fully solid. These partly liquid pollutants are otherwise known as aerosols. Aerosols can be found in nature in the form of sea salt, dust, and volcanic ash, while man-made aerosols come from coal combustion, factory and auto emissions, and biomass burning in farms and the countryside.

How Are PM 2.5 Particles Created?

PM 2.5 particles can come from many sources, and that’s the main reason why PM 2.5 is a very complex kind of pollution. Wildfires, power plants, and specific industries emit the particles directly, which is why they’re known as “primary sources.” On the other hand, we also have secondary sources for PM 2.5 particles that are created when different chemicals mix in the air. For example, new particles or compounds, some smaller than 2.5 PM microns in size, are formed when coal power plants or car exhaust chemicals combine with sunlight and water vapor in the air.

There are countless ways in which these particles are made, and of course there’s always a number of other factors to consider such as weather, geographic location, climate, and human activity. That said, it becomes clear that it’s almost impossible to know precisely what compounds are included in the PM 2.5 particles, since the concentrations of those compounds always vary.

It’s important to note that there are also indoor sources of PM 2.5 that may have adverse effects on human health even with a pollution-free outdoor environment. Coal fires, cooking odors, and even candles are some of the most common indoor sources of PM 2.5.

Why Is PM 2.5 Dangerous?

A higher amount of PM 2.5 particles in the atmosphere can cause health issues such as respiratory diseases, respiratory disease symptoms, and cardiovascular problems. What’s even worse, the way PM 2.5 particles interact with the human body can cause serious long-term effects on health. PM 2.5 particles first pass through the nose, and use the airflow in order to get to the end of the respiratory tract (the lungs) and accumulate there. When PM 2.5 particles set up camp in the lungs, they may go on to harm various parts of the body using the air exchange from the lungs to the rest of the body.

Additionally, PM 2.5 particles are highly threatening from a health perspective since they are extremely hard to remove from your body.  For example, PM 10 can be removed from the body through coughing and sneezing, but PM 2.5 particles can’t. This means that the best solution to potential PM 2.5 problems lies in prevention.

Although particulate pollution can harm anyone, some groups are in greater danger than others. Those with lung or heart problems, infants, young children, and the elderly are more prone to serious damage caused by these particles than the rest of the population.

How To Protect Yourself from PM 2.5 Outdoors

The first step for protecting yourself from serious particulate pollution levels outdoors is learning where and when dangerous levels of PM 2.5 occur. Environment agencies such as the Environmental Protection Agency (EPA) or the European Environment Agency (EEA) are dedicated to collecting and processing air quality data from different locations, and preparing air quality maps or air quality forecasts.

Since most people aren’t exactly weather or pollution experts, most of those maps include both particles and gaseous pollutants, and they also provide a basic overview which is easy to understand and use. EPA regulations state that there are several different categories of air quality based on the level of pollution. These categories are determined by the number of micrograms of a particular pollutant type per cubic meter of air (ug/m3). Below you will find the list of air quality levels for PM 2.5:

  • Acceptable/Good: 12ug/m3: Clean and safe air, no restrictions or other measures needed.
  • Moderate: 35 ug/m3: Unless you’re in a sensitive group, this level doesn’t require any outdoor activity restrictions. Those in high-risk groups need to keep an eye on their symptoms and reduce activity if breathing problems occur.
  • Unhealthy for Sensitive Groups: 55.4 ug/m3: People with asthma or other respiratory or cardiovascular problems should reduce their time outside as well as any outdoor activities.
  • Unhealthy: 150.4 ug/m3: With this much PM 25 particles in the air, everyone should reduce time outside, avoid outdoor activity, and keep the windows shut.
  • Very Unhealthy: 250 ug/m3: This level of PM 2.5 pollution is rare, but it happens on occasion, especially during wildfire seasons, or on hot windless days. All outdoor activity should be avoided.
  • Hazardous: 350.4 ug/m3: Luckily, this level of pollution is still very rare. It may occur in cases of major smog or spread-out wildfires. On this level, everyone should stick to protective measures. This especially applies to at-risk groups such as the elderly or people with heart /lung disease. In case your area seems to be reaching hazardous levels of air pollution frequently, you should definitely consider moving to a cleaner city or town.

Main Takeaways

In case air pollution levels in your area appear high, make sure you cut down the time you spend outside and limit outdoor activities. Be extra careful if you have cardiovascular or respiratory problems such as asthma. Track the times of the day when pollution levels decrease, as it’s definitely safer to go outside then.

Another piece of advice when it comes to protection from air pollution is to wear a face mask. Face masks rated to filter out the PM 2.5 particles can cut down the amount of PM 2.5 that you inhale significantly. Keep in mind that the mask should fit snugly on your face, since any potential gaps might increase the chances of PM 2.5 particles entering the body.

A long-term solution when it comes to resolving PM 2.5 particle pollution requires better organization and more time. Civic initiatives and environmental organizations may eventually make a huge change. This might be time and energy consuming, but it’s still for the greater good. Voting for a greener option might also be a part of the solution, but it will take a long time.

How To Protect Yourself from PM 2.5 Indoors

Naturally, in case of high PM 2.5 levels outdoors, you should stay inside for as long as possible. Another tip here is to keep your windows and doors shut and use an air purifier.

Still, the first step won’t be enough to protect you from PM 2.5 particles, since they can form indoors as well. Keep the use of fans to the minimum, since fans can lift dust and other particles from the floor and other surfaces. If vacuum cleaning, make sure to use a vacuum cleaner with a HEPA filter, which controls the amount of dust that gets emitted. Also, try not to burn wood or candles indoors, and remember to always use ventilation when cooking or baking.

Next thing you can do to protect yourself from PM 2.5 pollution at home is to purchase an air purifier. Air purifiers are great for removing tiny, fine particles and also filtering out airborne chemicals from the air.

Final Words

This concludes our comprehensive guide on what PM 2.5 is. Remember that PM 2.5 can be a dangerous group of pollutants, and that the outdoor air quality should be monitored in order for more specific steps to be taken.

We hope you liked the article and found it helpful. In case you still have some questions, feel free to post a comment, and we’ll do our best to provide you with the answer shortly.