New research links short-term PM2.5 exposure to decreased cognitive ability.

Recent research published in Nature Aging finds that short-term exposure to PM2.5 particles may affect cognitive ability.

The long-term affects of exposure to airborne hazards is well-known however, this recent research suggests that the short-term dangers may be more significant than previously thought.

The study measured cognitive impact using varying levels of PM2.5 and recorded the highest impact on cognitive ability after 21 to 28 days with PM2.5 levels of 8.52 to 10.25 μg per m3.

To provide some relevancy to those levels, view our Air Quality Monitor below to see current μg per m3 levels in your area.

4C Air has developed a new BreSafe nanotechnology and is offering a face mask that provides excellent protection from PM2.5 particles in areas with high exposure. The great benefit to these masks is the amazing breathability they have while also providing a high level of filtration for the wearer.

Click here to view these masks.

The full study is referenced below.


Ryan, J., Owen, A.J. The impact of the climate crisis on brain health. Nat Aging (2021).

How the next generation of face masks is changing PPE.

Nanotechnology is changing the future of PPE and environmental protection.

At the forefront of this technology is 4C Air; a startup out of Silicon Valley founded by two Stanford University professors.

Professor Yi Cui; a world-leading expert in materials science, energy, and environmental technology.  And Professor Steven Chu; a Nobel Prize winner and former US Secretary of Energy (2009-2013). Together, they have developed a patented nanotechnology material that’s poised to disrupt the mask and filtration industry.

The material produced is compromised of microscopic “nanofibers” which are layered to create a surface that can be used to filter extremely small particles PM2.5 and below. 

The implications for this new technology are massive since the nanomedia can be used in near-limitless filtration applications. 

The big benefit to this emerging tech is the extremely high filtration efficiency it achieves while allowing air the move through it-A feat that is difficult for current filtration technology to achieve because of the thickness and the type of material used.  

Why is this game-changing for face masks and respirators? 

Because it solves some of the biggest problems associated with wearing a mask.

What are the biggest problems with face masks and respirators?

There’s a balancing act that mask wearers have faced for years.  The challenge with current mask options for both the average person and healthcare professionals is a balancing between high-filtration and comfort or breathability.

The main purpose of wearing a face mask is simple: provide protection against “things” in the air and sadly, the average cloth mask a person wears, while comfortable, does very little to actually filter airborne hazards.

On the opposite hand, those who wear high effectively filtering face pieces such as N95 respirators often have to deal with several uncomfortable side effects including: 

  • Restriction to breathing
  • Dermatitis due to lack of airflow on area worn
  • Difficulties understanding speech. 

These are just a few. Masks that are very breathable and comfortable are most likely to have poor filtration. 

Increasing filtration efficacy is usually done by increasing the amount of filtration material which makes the mask more dense causing the issues mentioned above.

4C Air is hoping to change this and has created a new type of face mask using nanotechnology that bridges the gap between high levels of filtration and comfort. 

To really appreciated how this new technology will benefit mask wearers, it’s best to look at the pros and cons for different types of masks that are available today.

The Pros and Cons of different mask and respirator categories.

There are several categories of masks available to both healthcare professionals and individuals. Let’s take a look at the different types and how their filtration and breathability and comfort compare.


Cloth & Homemade Masks

Pattern Cloth Face Mask with Flexible Ear Loops


  • Allows for large variety of patterns, colors, styles
  • Protects against large droplets, coughs, sneezes
  • Washable and reusable
  • Can be more eco-friendly (organic/recycled cotton, silk, wool)
  • Comfortable to wear


  • Low filtration efficacy (based on material can range from 1%-60%)
  • Reusability (washing degrades filtration efficacy by wearing down fibers and creating gaps)
  • Can increase dermatitis (moisture gets trapped in material harboring more bacteria)

Cloth Mask Filtration Tip: Layer with another mask to increase filtration and overall protection.  Check out our article on how to potentially increase filtration for various mask materials using static electricity.

Surgical Masks (US Standard ASTM1 - ATSM3)


  • Inexpensive
  • Good Fluid Protection against large droplets, coughs, sneezes
  • Good breathability
  • Comfortable
  • Certified protection grades


  • Poor Seal Fit (results in lower air particle filtration effacacy)
  • Not recommend for PM 2.5 protection
  • One-time usage
  • Mouth contact-creates bacterial buildup in mask

NIOSH Respirators (US Standard N95 -N99)

n95 face mask


  • Excellent fine particle and airborne hazard filtration
  • Certified protection grades


  • Requires Fit Testing 
  • Only recommended for Healthcare providers
  • Can have difficulty breathing
  • Often uncomfortable
  • Can cause skin issues

FPP Respirators (EU Standard FPP1 - FPP3)

FPP EU Standard Masks


  • Great fine particle and airborne hazard filtration
  • Certified protection grades


  • Primarily purchased and used in Europe
  • Can have difficulty breathing
  • Can cause skin issues

KN95 Face Masks (China & Korean Standard GB2626 - 2019)

FPP EU Standard Masks


  • Great fine particle and airborne hazard filtration
  • Certified protection grades


  • Potential fakes 
  • Can have difficulty breathing
  • Can cause skin issues

4C Air Nanotechnology Masks

Nano Masks - KN95 particulate masks for PM 2.5


  • KN95 certified filtration higher
  • Great pm2.5  fine particle and airborne hazard filtration
  • Very breathable
  • Paper thin
  • Large, Medium, & Kid Sizes


  • No medical certification (yet)