Indoor Air Quality — A Collection of Introductions
Over the past year, I’ve written 9 introduction posts on different aspects of indoor air quality. This post collects them all:
Indoor Air Quality General Introduction
Ventilation
CO2
Filtration
Upper room UV
Far-UV
UV Light Against Diseases
Humidity
Air Distribution
Indoor Air Quality General Introduction
Indoor air quality is simply about ensuring the concentration of pollutants is maintained at acceptable levels. This post deals with:
- What the main pollutants are
- Harm caused by air pollutants
- How to prevent them from entering the space
- Technologies to remove pollutants
- Systems to remove pollutants
- What standards exist to control pollutant levels
- How to monitor and regulate pollutants
Ventilation
Ventilation generally refers to supplying outdoor air to a space. It is the main tool used to control indoor air quality. This post discusses:
- Why ventilation is needed
- Different types of ventilation
- Different ventilation equipment
- Measuring and checking ventilation
- Solving ventilation problems
- Improving ventilation
CO2 Monitoring
Many air pollutants can be monitored, but carbon dioxide is the most useful. This post discusses:
- What is CO2
- Why monitoring CO2 is important
- What levels are safe, acceptable, good for IAQ, and good for airborne disease mitigation
- Using CO2 to assess risk of airborne transmission
- Alternatives to monitoring CO2
- How to use a CO2 monitor
Filtration
Filtration is the second most commonly used method to improve indoor air quality after ventilation. It can remove particulate matter which the most harmful pollutant and includes airborne diseases. This post discusses:
- What is filtration
- Filter properties
- HEPA filters
- MERV filters
- Portable air cleaners
- Advantages and disadvantages of filtration
Upper Room UV
Going back 80 years, shining UV light above everyone’s head was a method used to reduce measles transmission. It is one of the most effective tools to mitigate airborne disease transmission available today, but still rarely used. This post discusses:
- How it works
- History of upper room UV
- Types of fixtures
- Dosing
- Placement
- Safety
- Where and how to buy
- Installation and maintenance
Far UV
Far UV is a new use of a type of UV light which can be shone in occupied rooms. It has the potential to be the most effective tool possible against airborne diseases. This post discusses:
- What is far-UV
- What is special about far UV
- How effective is it
- How is it created
- Where can you buy it
- Personal far UV
- Safe use
- Ozone concerns
- Why we don’t have it everywhere
UV Light Against Diseases
Upper room UV and far UV are the two most promising technologies using UV to mitigate airborne disease transmission. However, there are many different ways UV can be used, some are effective, some are ineffective and some are dangerous. This post discusses them:
- How is UV light created
- Surface cleaning
- Use in air handling units
- UV in a box
- Upper room UV
- Far UV
- UV photocatalytic oxidation
Humidity
Humidity levels in the air are linked to airborne disease transmission risk, but are primarily a comfort issue. Both high and low humidity can have bad effects. This post discusses:
- What is humidity
- The psychrometric chart
- Health effects of humidity
- Dangers of high humidity
- Humidity standards
- Types of humidifiers
Air Distribution
Air distribution is a neglected aspect of indoor air quality. We generally focus on air supplied to a room, but ignore how the air moves throughout the room. Poor air distribution can reduce the effectiveness of air cleaning methods by as much as 50%. It is critical to understand the role of air distribution on indoor air quality. This post discusses:
- What is air distribution
- Causes of poor air distribution
- Calculating air distribution
- Diagnosing air distribution problems
- Improving air distribution
- Short range airborne disease transmission
- HEPA filters and blowing the virus around
- Personal HEPA filters
- Plexiglass barriers
