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Camfil Air Filter Experts Explain PM 2.5 and New Research from Harvard T.H. Chan School of Public Health Highlights the Importance of Indoor Air Quality and Proper Ventilation.

By September 23, 2021 No Comments
10–12 minutes to read

A new study published on September 9 in the journal Environmental Research Letters has revealed a link between short-term exposure to fine particulate matter and acute decreases in cognitive function. The research was led by the Harvard T.H. Chan School of Public Health. 

The study, which took place over the course of one year, consisted of 300 office employees across six different countries (China, India, Mexico, Thailand, the United Kingdom, and the United States), with participants ranging in age from 18 to 65. The participants in the study worked at least three days per week in the office and were assigned a permanent work station, which was equipped with an environmental sensor to collect real-time measurements of PM2.5 and CO2. Each participant also had an app custom-designed for the study installed on their phone to test cognitive abilities. 

The data collected showed that higher concentrations of PM2.5 and lower ventilation rates correlated with slower response times and reduced accuracy on a series of cognitive tests. Importantly, the research team observed that cognitive function was impaired at concentrations of PM2.5 and COz that are common in indoor environments such as office buildings. 

This study is yet more evidence that indoor air pollution threatens not only the health but the productivity of office employees. 

What is PM2.5? 

Particulate matter, or PM, is defined as any solid or liquid particles that are light enough to remain suspended in the air. Particulate matter is assigned size classifications based on their diameter in microns — PM10, PM2.5, PM1. 

PM2.5, which is sometimes referred to as fine particulate matter, is 2.5 microns in diameter or less and can cause serious long-term health damage when inhaled. Particle pollution can come from a variety of sources, including car exhaust from traffic and wildfire smoke. Additionally, some of the respiratory droplets that are responsible for spreading the COVID-19 virus could be classified as PM2.5. 

In addition to decreased cognitive function, PM2.5 has been linked to increased symptoms of conditions such as seasonal allergies, COPD, and asthma. 

Where Does Indoor Air Pollution Come From? 

Indoor air can be up to 50 times as polluted as outdoor air. In addition to particulate matter, gaseous pollutants can exist at high concentrations indoors. Gaseous pollutants, such as ground-level ozone, are also known to have health effects, including dizziness, nausea, and shortness of breath. 

Indoor air pollution in office buildings comes from multiple sources, which may include: 

  • Outdoor sources. Outdoor sources of air pollution usually enter the building through  HVAC systems with inadequate air filters, doors, windows, and on people’s clothes. In poorly ventilated buildings, this pollution becomes trapped once it has entered, leading to a build-up of high concentrations of pollution indoors over time. Buildings close to high-traffic roads or in dense urban areas are particularly vulnerable to poor indoor air quality as a result of outdoor sources, such as car exhaust fumes.
  • Cleaning chemicals and air fresheners. Cleaning chemicals that are allowed to accumulate in the air due to poor ventilation can be a major contributor to poor indoor air quality. Similarly, air fresheners can linger in the air and worsen indoor air quality. This issue is of particular salience due to the increased frequency and intensity of cleaning and sanitation procedures in offices to combat the spread of COVID-19. 
  • Furniture and furnishings. Cheap, mass-manufactured furniture is a common source of VOC (volatile organic compound) off-gassing. Volatile organic compounds such as formaldehyde can cause adverse health effects. Printers, copier machines, and other office equipment that use large quantities of ink also emit VOCs. 
  • Building inhabitants. Additionally, a commonly overlooked source of indoor air pollution is the building’s inhabitants themselves, who can bring in pollen, pet dander, dust, and other particulate matter on their clothing. Human skin cells are also a large contributor to the buildup of dust, with the average person dropping approximately 40,000 skin cells every single minute. Respiration also adds moisture to the air, and respiratory droplets can carry dangerous pathogens, including the SARS-CoV-2 virus. 

How to Improve Indoor Air Quality for Better Cognitive Function Among Office Employees

The U.S. Environmental Protection Agency (EPA) recommends three steps for commercial facilities managers to improve indoor air quality: identify pollution sources, improve ventilation, and implement air filtration. An air filtration expert can guide you through this process and help find the best combination of solutions to fit your building’s needs and budget. 

What Are recommendations from Camfil’s air quality experts? 

30/30 Dual 9 Panel Air Filter 

Camfil’s 30/30 Dual 9 is specifically engineered to increase particle capture efficiency, lower energy consumption, and last longer than any pleated panel filter before it. As the longest-lasting pleated filter on the market, the Dual 9 is guaranteed to maintain its rated efficiency throughout the filter lifetime of nine to twelve months. 

What is Camfil’s City M Air Purifier? 

The City M air purifier includes both a HEPA filter and an activated carbon filter to remove particulate and gaseous pollutants from the air. The City M air purifier consumes 50% less energy than units of similar size, and operates independently of a building’s HVAC system, making it a good option for any space This in-room air purifier is very quiet, making it ideal for use in offices and other public building spaces. 

Read more about the City M here

What is CamCleaner CC500 Air Purifier?

The CamCleaner CC500 air purifier was originally designed early in the pandemic for hospitals that needed to create negatively pressurized isolation areas. The unit was also engineered to serve as a standalone air purifier for offices, schools, and other public buildings. The CC500’s MERV-9/9A prefilter extends the life of the 99.995% HEPA filter, leading to lower overall running and maintenance costs.

About Camfil Clean Air Solutions

For more than half a century, Camfil has been helping people breathe cleaner air. As a leading manufacturer of premium clean air solutions, we provide commercial and industrial systems for air filtration and air pollution control that improve worker and equipment productivity, minimize energy use, and benefit human health and the environment. We firmly believe that the best solutions for our customers are the best solutions for our planet, too. That’s why every step of the way – from design to delivery and across the product life cycle – we consider the impact of what we do on people and on the world around us. Through a fresh approach to problem-solving, innovative design, precise process control, and a strong customer focus we aim to conserve more, use less and find better ways – so we can all breathe easier.


The Camfil Group is headquartered in Stockholm, Sweden, and has 33​ manufacturing sites, six R&D centers, local sales offices in 30 countries, and about 4,80​0 employees and growing. We proudly serve and support customers in a wide variety of industries and in communities across the world. To discover how Camfil Canada can help you to protect people, processes and the environment, visit us at