Page 44 - OHS, October 2021

IH: INDOOR AIR QUALITY
More people are paying attention to air quality in the spaces we use for work, school, entertainment and travel, and building owners are looking for ways to create cleaner air to instill occupant confidence.
Effffective monitoring solutions of CO2 levels can be combined with other factors and used as an indication of when conditions may be present that could increase the risk of potential exposure to some viruses.
Based on CO2 measurements and occupancy levels, the intake of outdoor air can be adjusted and increase the flow of air indoors. A target benchmark for good ventilation of CO2 readings should be set below 800 parts per million (ppm).10 This approach requires periodic measurements of the CO2 level, comparison with the benchmark and adjustment decisions based on these and other relevant parameters that vary depending on each individual application.
By monitoring for CO2 levels in enclosed spaces, building occupants can use the information as an indication of when conditions may be present that could increase the risk of potential exposure to some airborne viral transmissions and can use that and other relevant parameters to take any actions they deem appropriate, like increasing ventilation in a space.
t
occupant wellbeing,5 including coughing, shortness of breath or aggravating asthma: eye, nose and throat irritation, headaches and allergic reactions. It can even potentially increase the risk of spreading some airborne viruses.6 Buildings with outdated HVAC and ventilation systems can foster environments where the risk of airborne virus transmission could increase, so deploying strategies to help improve indoor air quality is a key step to healthier places of work, school and leisure.
Maintaining good indoor air quality
Proper ventilation and good air flow can also help to make a more productive environment.7 There is not one solution to solving indoor air quality – it takes a layered approach looking at ventilation, fresh air intake, pressure, humidity, temperature and filtration. When thinking about the ways in which IAQ can be addressed, here are three steps to consider:
Continuously Monitor CO2. When it comes to air quality monitoring, sensing technology is an important tool to identify opportunities for indoor air quality adjustments. IAQ sensors that monitor a building’s environmental state and air quality status offer an effective, automated solution. The concentration of CO2 indoors is one indoor air quality parameter to consider and might indicate when additional fresh air intake is needed. By having a constant check on the concentration of CO2 indoors, it can help when deciding whether to adjust the amount of outdoor air delivered into a space.
In order to keep track of indoor air quality, CO2 monitoring products8 are useful tools as they can provide information that can be used to analyze the quality of air inside enclosed spaces. Research conducted by scientists at the University of Colorado9 has shown that real-time monitoring of indoor ambient air can be an indicator of potential increased risk of some airborne viral transmissions, using different levels of risk-based factors, including for example CO2 concentration levels and the type of human activity in the area. CO2 levels can be used as a reference point for exhaled air and, when coupled with other factors and parameters, can be part of an indicator of the risk of potential exposure to some airborne viral transmissions.
Provide Adequate Ventilation. Proper ventilation of indoor spaces helps maintain a healthier environment. According to studies and guidelines from government agencies including the Centers for Disease Control and Prevention (CDC) and the EPA, proper ventilation and filtration are effective ways to help reduce or remove unwanted particles including pathogens, pollutants and other irritants from the air. Outlined below are some recommended ventilation interventions from the CDC11 that can help improve IAQ.
■ Increase fresh air intake. Adjust mechanical systems to allow for the maximum fresh air intake and for buildings without mechanical controls, open windows and doors to bring outside air indoors, when outdoor conditions allow.
■ Maximize ventilation. Adjust building controls to increase airflow throughout the building.
■ Improve filtration systems. Improve air filtration with MERV13 filters or higher. There are even air filters in development with chemical bonding technology that can capture and inactivate up to 97 percent of the SARS CoV-2 virus that causes COVID-19. Condition-based maintenance software can monitor particulate matter and volatile organic compounds to identify if filters require changing based on need versus a maintenance schedule to avoid costly, unnecessary filter changes.
■ Check current exhaust ventilation systems. For rooms where exhaust fans are used regularly, such as restrooms, kitchens and labs, make sure the fans are fully functional and are turned on any time the space is in use. Additionally, air should flow toward the exhaust intake to support the elimination of any pollutants.
Manage Temperature and Humidity. Air quality strategies should also include steps to manage temperature and humidity. In many cases, the optimal range for humidity is around 40-60 percent, as this is where the communication of viral pathogens is at its lowest.12 It is more difficult to control the spread of potential infections in excessively dry conditions. On the other hand, excessive humidity promotes the growth of dust mites and fungi, which are known to exacerbate respiratory conditions and allergies.
If left unattended, moisture can lead to mold growth, which can, in turn, lead to allergic reactions, such as sneezing, runny nose, red eyes and skin rash. If excess moisture does lead to mold in an indoor
i
it
h
h
a
a
r
rd
d
e
e
r
rt
t
o
o
r
r
e
em
ma
a
i
in
na
a
l
le
er
r
t
t.
.
I
I
n
nd
d
o
oo
or
ra
a
i
i
r
rp
po
o
l
ll
l
u
ut
t
i
io
on
nc
c
a
an
n
a
a
l
ls
s
o
oi
im
m
p
pa
a
c
c
t
t
40 Occupational Health & Safety | OCTOBER 2021
www.ohsonline.com