Introduction
When speaking of seasonal allergies many people—those without seasonal allergies—believe it to be largely limited to springtime. However, seasonal allergies are a four-season human health issue. Recent studies have shown that seasonal allergies cost employers $600 per employee due to absenteeism and lost productivity. While this may seem like a small figure, when compared to other chronic health conditions such as stress, depression, and anxiety it is higher. According to other scientific studies, seasonal allergies were the most widely reported health condition in the workplace with 55% of employees reporting symptoms. This same study also found that for those who did report allergy symptoms reported having them over 50 days per year on average resulting in 3-1/2 sick days taken per year. It has been estimated that the cost associated with absenteeism and lost productivity due to seasonal allergies for employers to be $5 million annually.
As the studies referenced above attest, particulate matter in the air degrades the indoor environment. These airborne particles exacerbate respiratory problems such as seasonal allergies as well as asthma, emphysema and chronic lung disease. Air filtration reduces the exposure of building occupants to these airborne contaminants. But, how do you do it? The answer is more MERV.
Filters: More MERV
One way to offset the negative impacts on human health issues affecting building owners such as seasonal allergies is to install and maintain air filters capable of effectively removing the tiny particles that are the source of the problem. The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) establishes the test procedure for evaluating the performance of air-cleaning devices as a function of particle size. The standard—ASHRAE 52.2-1999: Method of Testing General Ventilation Air-Cleaning Devices for Removal Efficiency by Particle Size—addresses two performance characteristics: 1) the ability of the device to remove particles from the air stream, and 2) its resistance to air flow. Rather than providing consumers with a bunch of technical terms, ASHRAE simplifies these performance characteristics using a single metric known as the Minimum Efficiency Reporting Value, or MERV. Simply put, the higher the MERV value—MERV efficiency categories range from 1 to 16—the more effective the airborne particle removal.
In the past, improved filtration necessarily meant an increased pressure drop across the filter, and, thus increased energy consumption. Today’s filter designs, however, include superior materials to what was used in the past resulting in your HVAC system being able to deliver cleaner air and no additional operational cost. The newer, typically synthetic, materials being used in today’s filters also resist moisture which can lead to bacteria growth and have a greater ability to keep a captured particulate than the materials of filters past.
Maintenance and System Applications
As with any technology or equipment, it is critically important to establish and implement a regular maintenance and replacement schedule of filters. Also, it is important to keep in mind your system’s filter requirements and designed pressure drop. Facility managers are strongly encouraged to check their systems requirements to determine what the best and most cost effective filter type is.
Conclusions
As Americans, we spend 90% of our time indoors thus the indoor environment of buildings plays a critical role in human health of everybody. While indoor environmental quality is a broad discipline, there are some relatively simple things that facility managers can and should consider to improve the health and productivity of their building’s occupants. For facility managers, considering replacing your air filters with ones having a higher MERV is, well, nothing to sneeze at. If done properly it can significantly reduce the airborne particulates within the building while improving employee productivity and lost time due to sick days.
LEED-EB credit 5.1—Indoor Chemical and Pollutant Source Control: The primary goal is to reduce particulates in air distribution to improve the indoor environment as indoor air pollutants are known to have a significant negative influence on human health.
Links
U.S. Green Building Council© (www.usgbc.org)
The USGBC’s LEED for Existing Buildings program (LEED-EB) specifically addresses air filtration in LEED-EB Credit 5.1 – Indoor Chemical and Pollutant Source Control.
ASHRAE (www.ashrae.org)
Establishes the test procedure for evaluating the performance of air-cleaning devices as a function of particle size.
U.S. Environmental Protection Agency, Indoor Air Quality Division (www.epa.gov/iaq)
This site offers information about a whole range of indoor air quality issues including products, human and environmental health effects, and laws and regulations.
