Bioaerosols exposure and potential impact on human health is a growing concern.
Bioaerosols are assemblies of particles of variable biological origin (bacterial, viral, or fungal) suspended in the air and capable of initiating an infectious process in a susceptible host.
As illustrated in figure 1, tests show that filter materials are very efficient at removing small particles (<0.1 of um diameter) from air streams because electrostatic charge and Brownian motion trap these fine particles within the matrix of the fabric. Larger particles (>1.0μm in diameter) such as bacteria or fungi are also efficiently removed by mechanical filtration.
However, filtration media are generally poor at removing particles in the range from 0.1μm to 0.5μm in diameter, which are small enough to escape the forces of mechanical filtration yet are large enough to avoid being entrapped by electrostatic or Brownian motion.
This “weakness window” unfortunately corresponds to the mean size of many viruses.
In order to be protected you need to use the right mask that is designed to protect the wearer from the environmental pathogens.
Many people, mistaken think that using surgical mask, will be protected. This not true.
Surgical masks are designed to protect the environment from the wearer, not the way around.
Usually Surgical masks are also meet the Medical Device class 1 standards.
In Europe the standard for medical devices is EN14683: 2006
On the other hand, Respiratory Mask are designed to protect the wearer from the environmental airborne pathogens. This masks belong in the Personal Protected Equipment category.
If you need to be protected from pathogens in the environment, bioaerosols or not, you need to use Respiratory Masks, not Surgical Masks.
Different regions in the world use different standards that describe the requirements that need to be met, in order for a mask to be certified and labeled as PPE.
For Example in N. America, the NIOSH determin the requirements and the respirator masks are label as N95, N98, N99 depending the filtration they provide.
In Europe there is the European standard EN149 2002 +A1:2009 that determins the requirments and the masks are labeled FFP1, FFP2, FFP3.
In Australia are labeled P1, P2, P3 and in Japan DS1, DS2, DS3.
Some manufactures, produce masks that meet the requirements for both PPE and Medical Device Surgical masks.
A comparison between NIOSH and European Standard masks was performed from the University of Oxford, in behalf of the British Occupational Hygiene Society. You can read the article in the following pdf.
Comparison of Nanoparticle Filtration Performance of NIOSH vs CE
