In the modern world, we spend so much time indoors that the indoor environment is practically our natural environment. So it’s only natural that we’re deeply affected by these interior spaces.
People can thrive in buildings with a healthy environment. But if there are issues with a building’s air, the results can be costly, both financially and in terms of human health.
Fortunately, there’s much that you can do to improve the environment within any four walls, starting with the air you breathe.
IEQ, Indoor Environmental Quality, concerns the impact of everything you feel, see and hear inside a building. Natural daylight access, noise levels and control over room temperature can all make a difference to IEQ.
Where clean air learning comes to life
The response to IEQ University and PDH credits has been remarkable. We are transitioning to a new digital platform to provide an enhanced user experience. Check back soon to enroll in the updated modules.
IEQ 101
1 Credit Hour
Start here to learn or review the essentials of IEQ and Indoor Air Quality (IAQ). Topics include methods for measuring airborne pollutants and controlling IAQ.
IEQ 201
1 Credit Hour
Continue your IEQ journey and learn how to make a greater impact on commercial environments. Discussion includes best practices for IAQ control and an overview of industry guidelines.
IEQ 301
1 Credit Hour
Advance your understanding of IEQ and learn strategies for managing indoor air quality. Concepts include impacts on productivity, ESG and sustainability concerns and recently introduced IAQ technologies.
Click each foundation on the left hand menu to learn more.
*Source: Harvard T.H. Chan School of Public Health
When you’re designing a building or maintaining a space, there are 9 foundations to consider for protecting human health and improving quality of life.*
Addressing shortcomings in these areas is also vital to protecting productivity and controlling energy usage.
When you’re designing a building or maintaining a space, there are nine foundations to consider for protecting human health and improving quality of life.*
Addressing shortcomings in these areas is also vital to protecting productivity and controlling energy usage.
Meet or exceed local guidelines for outdoor air. Filter outdoor and recirculated air with a minimum removal efficiency of 75% for all particle-size fractions including nano.
Choose supplies, furnishings and building materials with low chemical emissions. Check for lead, PCBs and asbestos. Use a vapor barrier. Maintain humidity levels between 30-60%.
Meet minimum thermal comfort standards for temperature and humidity and keep thermal conditions consistent throughout the day. Provide individual level thermal control.
Conduct regular inspections of roofing, plumbing, ceilings and HVAC equipment. When moisture or mold is found, immediately address source and dry or replace contaminated materials.
Use high-efficiency filter vacuums and clean surfaces regularly. Seal entry points, prevent moisture buildup and remove trash. Avoid pesticide use.
Meet fire safety and carbon monoxide monitoring standards. Provide adequate lighting and use video monitoring, interactive patrols and incident reporting. Maintain an emergency action plan.
Meet the U.S. National Drinking Water Standards. Install purification system, if necessary. Ensure residual disinfectant levels are sufficient to control microbes, but not in excess. Prevent stagnation in pipes.
Protect against outdoor noises and control indoor noise, such as mechanical equipment. Provide spaces that minimize background noise to 35dB and a maximum reverberation time of 0.7 seconds.
Provide as much daylight and/or high intensity blue-enriched lighting as possible. Provide direct lines of sight to windows from all workstations. Incorporate nature and nature-inspired design indoors.
Things to consider for good IEQ
Protecting human health and quality of life is the most important consideration in addressing IEQ, yet taking care of those conditions can also have other benefits. Improving an indoor environment may have a positive impact on financial considerations like employee productivity, conservation of natural resources and building resale value.
Select an industry from the menu below to learn more about protecting its unique indoor environment.
Many of us spend so much time indoors that the indoor environment is practically our natural environment, so it’s only natural that we’re affected by the quality of these interior spaces. We can thrive in buildings with a healthy environment, but if there are issues with a building’s IEQ, the results can impact our quality of life in several ways — such as comfort, well-being, long-term health and productivity.
Bringing the elements of IEQ into balance is important to creating a comfortable environment. Indoor air filtration solutions can help control odors and reduce allergens, such as pollen and mold, that can lead to sneezing and watery, itchy eyes. It’s a vital part of improving how people feel.
The environment indoors can affect virtually every aspect of our lives — from sleep quality to mental health. Evidence has emerged of ties between poor air quality and poor mental health. Creating a safe and healthy work environment has also been found to help minimize tensions at work. Selecting the right air filtration solution is one key to protecting the quality of working environments.
Poor IEQ can do more than just make people uncomfortable; in particular, some common indoor air pollutants are linked to immediate and lasting health effects. For example, radon is the second leading cause of lung cancer. Smoke can contain toxins such as lead and formaldehyde. Appropriate filtration and ventilation can help reduce these toxic gases and particulates indoors.
When IEQ falls, productivity can, too. Research found that increased contaminants and lower ventilation rates — at levels common within indoor environments — are associated with slower response times and reduced accuracy on cognitive tests. In schools, ventilation rates and CO2 concentration have been linked to attendance rates. Specific clean air solutions can help address the IAQ in these unique environments.
Many organizations around the world have established trusted standards, guidelines and recommendations for Indoor Air Quality and Indoor Environmental Quality. American Air Filter follows the guidance of these respected entities to provide assurance to our customers.
Click each logo to learn more.
Outdoor air quality can affect indoor air, and it isn’t always predictable. This interactive map from the U.S. EPA allows you to visualize the quality of outdoor air at monitoring stations across the United States, Puerto Rico and the U.S. Virgin Islands.
Tap or click the map to get started.
ASHRAE 241 represents a significant advancement in how we approach indoor air quality and public health in buildings. Released in June 2023, this standard establishes a framework for managing infectious aerosols in indoor spaces, with implementation of new filter requirements beginning January 2025.
At its core, the standard addresses a fundamental question: How can we make indoor spaces safer from airborne disease transmission? The answer lies in a comprehensive approach that considers three interconnected factors. First, it examines the number of people in a space, as occupancy directly affects the potential for disease spread. Second, it considers the amount of fresh outdoor air being introduced into the building. Third, and perhaps most critically, it evaluates the effectiveness of air cleaning systems, particularly focusing on filtration.
The standard introduces an important shift in how we measure filter performance through the MERV-A rating system. This approach is more rigorous than previous standards because it measures filter performance after simulated long-term use, typically equivalent to about six months of operation. This change is particularly significant because not all filters perform the same way over time. Traditional mechanical filters made from glass fiber maintain, and even increase from, their initial performance level, while electrostatically charged media filters (made from synthetic materials) may experience some decrease in efficiency over time.
Building managers and operators have several paths to achieve compliance with ASHRAE 241. They can increase the amount of outdoor air brought into the building, install more effective filtration/air cleaning systems, adjust occupancy levels, or implement a combination of these strategies. The flexibility of this approach allows buildings to choose the most practical and cost-effective solution for their specific situation.
The implementation of this standard marks an important evolution in building management practices. While it isn't currently mandated by regulatory bodies, it provides clear, science-based guidelines for creating healthier indoor environments. This is particularly relevant in our post-pandemic world, where awareness of airborne disease transmission has heightened significantly.
The standard operates during what's called "Infection Risk Management Mode", though it doesn't specify exactly when this mode should be activated. This gives building operators the flexibility to implement these stricter air quality measures when they deem necessary, such as during local disease outbreaks or seasonal illness peaks
One of the most practical aspects of the standard is how it links filtration efficiency to occupancy levels. Buildings using higher-rated filters (particularly those above MERV 11-A) can safely accommodate more occupants. This creates a clear, quantifiable connection between air quality investments and building utilization, helping justify upgrades to filtration systems.
For building operators and facility managers, understanding and implementing ASHRAE 241 represents an opportunity to take a proactive approach to occupant health and safety. While the technical aspects of the standard may seem complex, the goal is straightforward: create indoor environments that better protect people from airborne infections while maintaining practical and efficient building operations.
ASHRAE 241 Calculation Guide Explained
The calculations in ASHRAE 241 might seem complex at first, but they're designed to create a clear relationship between clean air delivery and occupancy safety. The key insight is that you can achieve compliance through multiple approaches: bringing in more outdoor air, improving filtration, or managing occupancy levels.
What makes these calculations particularly practical is that they allow building managers to make informed decisions about tradeoffs. For instance, if increasing outdoor air intake is expensive due to heating/cooling costs, they might choose to invest in better filtration instead. The calculator provided in the standard helps make these decisions more straightforward.
ASHRAE 241 Clean Air Calculations Guide
Core Formula for Minimum Clean Airflow
The fundamental calculation in ASHRAE 241 determines the minimum equivalent clean airflow rate (VECAi) required in a space:
VECAi = ECAi × PZ,IRMM
Where:
Total Clean Airflow Requirement
To meet the standard, the following equation must be satisfied:
(zf × VOT) + VVMS + VACS + VNV ≥ VECAi
Where:
Filter Effectiveness Calculations
The standard uses weighted calculations to determine filter effectiveness:
Practical Example: Hospital Waiting room
Consider an office space with these parameters:
Calculations:
If the standard requires 30 CFM/person, this configuration would pass.
Ways to Improve Clean Air Calculations
To increase equivalent clean air, you can:
For hospitals, these calculations take on heightened importance due to the vulnerability of patients and the increased risk of infectious disease transmission. Let's consider different hospital areas and how the calculations would apply:
In a typical patient room: The standard would require higher clean air rates due to the presence of potentially infectious patients. If we assume a standard private room of 200 sq ft with up to 4 people (patient, two visitors, and a healthcare worker), the calculations would need to account for:
VECAi (Minimum Clean Airflow) would need to be higher than standard commercial spaces:
In more critical areas like:
Operating Rooms:
Emergency Department:
Isolation Rooms:
Emergency Department Waiting Area Calculation Example
Space Parameters
Base Calculations
Improvement Options
If higher clean air rates are needed:
1. Increase Filtration:
2. Increase Outdoor Air:
3. Add Supplemental Air Cleaning:
New per person: 75.8 CFM/person
