Breathe freely: What is PM2.5 and why you should care

Doesn’t it feel good to take a step outside and breathe in deeply? There are many health benefits to taking a whiff of fresh air. Namely, it can build up your energy and increase your lifespan.

But what if the air outside isn’t clean—even toxic? Air pollution is hard to escape, and the lack of visible smog is no indication that the air is healthy.

As the world becomes more populated, our engines are cranking out higher concentrations of harmful pollutants into the air, posing health risks for all. The most dangerous of these pollutants is PM2.5.

What is PM2.5?

PM2.5 is particulate matter with a diameter of 2.5 micrometers and smaller (about 3 percent the diameter of a human hair). These ultrafine particles, which are a result of power plant emissions, vehicle exhaust, residential heating, agricultural burning, forest fires, construction dust, household pollutants and dust storms, are small enough to slip past the respiratory system’s defenses with both short- and long-term health effects.

Acute, short-term effects include:

  •               eye, nose and throat irritation
  •               upper respiratory infections
  •               headaches
  •               nausea
  •               allergic reactions
  •               aggravated asthma and emphysema


It’s also the sixth highest risk factor for death worldwide, and a leading driver of long-term chronic illnesses such as:

  •                  lung cancer
  •                  heart disease
  •                  stroke

Growing populations and the lack of renewable energy sources greatly contribute to increasing levels of PM2.5. Sensitive populations (children, pregnant women, the elderly and those with pre-existing cardiopulmonary problems) should be more cautious of PM2.5 pollution and minimize outdoor PM2.5 exposure.

How can you protect yourself?

Cities and villages across the world are seeing toxic pollutants in the air exceed the average annual values recommended by the World Health Organization’s air quality guidelines. 

Air quality conditions can change rapidly. The Air Quality Index (AQI) ( can tell you how clean or polluted your outdoor air is on a daily basis and provides health messages with advice on how to protect your health.

Here are some precautions to take when air quality is moderate to hazardous:

  • Stay indoors, close all your windows and run your air conditioner if possible
  • Turn on your air purifier
  • Avoid vigorous activity that can make you breathe faster or more deeply
  • If poor air quality persists, consider moving to an unaffected location
  • If you must go outdoors, wear an N95 or higher face mask