The air we breathe in the environment is full of particles that are so small we can’t see them. Microorganisms like viruses, including the flu virus or the new coronavirus, as well as chemicals, allergens like dust and smoke, and other particles that can be carried in liquids, are there to cause us harm, but are invisible to the naked eye. Chemicals released into the air from the burning of fossil fuels are the main source for air pollution, which can be detrimental to human health.
The acronym PM is a term used to talk about “particulate matter”, referring to these small particles we can’t see with our bare eyes. Different environments have different amounts of PM in them, and certain activities or situations can influence the level of air pollution. For example, smoking, kerosene heaters, cooking, chemical cleaners, diffusion of essential oils, the use of aerosol hairsprays or deodorants, and having windows or doors open into outdoor environments that are severely polluted, can increase the number of PM inside a closed environment.
Even though the list of sources of air pollutants is very varied and extensive, some activities are considered to be the main contributors to air pollution. Some of these include forest fires, power generators, manufacturing of chemicals, vehicles, and emissions from industrial or agricultural sources.
The term PM 2.5 is used as a way to refer to those very small particles that have a specific diameter or size of 2.5 micrometers. To understand how small this is, you have to know that the human eye can perceive particles with a size of 0.1 millimeters. 2.5 micrometers are equivalent to 0.0025 millimeters, which means these particles can only be seen through very powerful microscopes.
What is the importance of these particles, you may ask. Even though the majority of the PMs are harmful to humans, specifically PM 2.5 are the source for concern in experts, since they believe this size is so small that they can not only deeply penetrate the lungs, but they could also enter the bloodstream, which leads to very serious consequences.
PM 2.5 can have very varied negative effects on the body, both long and short term. These effects can be seen with exposure to moderate to hazardous levels of PM 2.5, and some of the most common ones include: irritation of the eyes, throat, and nose, shortness of breath, wheezing and coughing, exacerbation of asthma, severe lung injury and decrease of their function, as well as decreased function of the cardiovascular system. The most severe complications can even lead to death.
Although these particles are harmful to everybody, certain groups of people are more sensitive to them, including kids and the elderly, immunocompromised patients, and those with other medical conditions.
The Air Quality Index (AQI) is a scale that goes from 0 to 500, used to measure the levels of PM in a specific environment. As we mentioned, levels of PM considered moderate can cause harm to human health, with the two main systems affected being the respiratory and the cardiovascular ones. Many websites track the air pollution around the world, like the Berkeley Earth and AQICN ones, where they show real-time maps of PM 2.5 levels around the globe.
Certain masks with removable filters meant to trap PM 2.5 can be used to protect against them. Reusable cloth masks and disposable face masks like the surgical masks are not recommended to protect against particles this small.
Masks used to protect against PM 2.5 come with a cloth pocket where the activated carbon filter is inserted. The filters can also be made out of activated bamboo pulp. Usually made with cotton and sometimes with the addition of foam, these masks can also come with a vent system to increase breathability. Without the filter, these masks can also be used for general protection.
Protection against smog, smoke, dust, automobile exhaust, mist, and chemicals should be achieved by this masks when they’re made with high-quality materials and when the fit for the wearer is perfect. But, enough research about these masks hasn’t been done to prove a definitive protection against these small particles.
The materials these masks are made of is usually cotton, but foam can be added sometimes to help with breathability. When filters are made with activated carbon, they can last up to 1 to 3 days. Some companies claim their filters have a lifespan of several months. Additional features of the mask are adjustable ear straps, or other types of straps.
A lot of people ask if these masks can be used for protection against viruses, particularly the SARS-CoV-2, which is the coronavirus responsible for COVID-19. This virus has a diameter of 50 to 200 nanometers, which is equivalent to 0.05 or 0.2 micrometers, much smaller than 2.5. There isn’t any evidence available that shows masks with PM 2.5 filters are effective for protection against COVID-19.
For virus protection during the pandemic, particularly in healthcare settings, the best face masks with the highest antiviral properties are the N95 masks, also known as the N95 respirators. These are often worn by healthcare providers along with goggles or face shields for eye protection, and KN95 masks can substitute them when they’re not available. Some popular models are the 3M 8210 and the 3M 8511, both 3M N95 masks.
Anyone who uses masks with PM 2.5 filters has to be aware that they may cause some side effects, like irritation of the eyes, breathing difficulty, and dryness of the mouth and nose.
In the United States, several options for PM 2.5 masks are available, including options to buy in bulk and wholesale online. But, in the USA, these masks are not recommended for protection against COVID-19.