Indoor environment in a digital future - Master thesis - s154397 - s153767 (1)

Exposure Limit TVOC [ppb]
1 Excellent no limit 0-65
2 Good no limit 65-220
3 Moderate < 12 months 220-660
4 Poor < 1 month 660-2200
5 Unhealthy hours 2200-5500
Table 2.3: TVOC guidelines from the German Federal Environmental Agency [37]
Other Inorganic Gases
Some of the most common nonindustrial indoor air pollutants amongst inorganic gasses are nitrogen
dioxide (NO2), ozone (O3) and carbon monoxide (CO). There are no specific danish regulations for
these pollutants in office environments, but the Danish Working Authority provides a list of limit values
for air pollution in general. These are presented in Table 2.4. Furthermore, SBi has provided guidelines
for a number of indoor air pollutants including NO2, O3 and CO. The guidelines indicate the effect
that the pollutant might have on the occupant under different levels of the pollutant. These are also
presented in Table 2.4. The American National Ambient Air Quality Standard (NAAQS) also provides
average daily (8 hours working day) limit values for the pollutants in indoor air. However, experts
recommend to maintain levels at 50% or less than the NAAQS [33].
Exposure to O3 can result in shortness of breath, throat and nose irritation for both healthy occupants
and even more so for individuals with preexisting airways diseases ie. asthma. The main sources of
O3 in offices are from outdoor air and air purifiers.
CO exposure can cause fatigue, headache and shortness of breath and even death in severe cases
with high exposures. The main sources of CO in offices are from gas appliances and environmental
tobacco smoke. However, the severity of CO poisoning is dependent on the concentration, time of
exposure, and the general health status of the exposed occupant.
Exposure to NO2 can lead to shortness of breath, coughing and wheezing. The main sources of NO2
in offices are from gas/heating appliances and roadside fumes from outdoor air.
Ozon Carbon Monoxide Nitrogen dioxide
Limit values for air pollution
Danish Working Authority 100 ppb 20 ppm 500 ppb
National Ambient Air Quality Standard 80 ppb 9 ppm 53 ppb
Sbi guidelines
Low/no effect <30 ppb <0.5 ppm <80 ppb
Medium effect 30-50 ppb 0.5-9 ppm 30-300 ppb
High effect >50 ppb >9 ppm >300 ppb
Table 2.4: Limit values for air pollution and guidelines [38] [31]
14 INDOOR ENVIRONMENT IN A DIGITAL FUTURE