Parameters Affecting Indoor Air Quality
Indoor air quality (IAQ) is a term which refers to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants. The quality of air inside the building including gaseous composition, humidity ,temperature and air contaminants.
Parameters affecting Air Quality
Physical Parameters
Chemical Parameters
Biological Parameters
1. Physical Parameters
Physical parameter . means any measurable physical characteristic of a substance including, but not limited to, temperature, electrical conductivity, pH, and specific gravity.
- Indoor Temperature
– Thermal Comfort is important part in IAQ
– Great source for IAQ complaints - Indoor Relative Humidity
– Associated with poor HVAC System
– Low RH leads to many symptoms of SBS
– Irritation to eye and throat
2. Chemical Properties
Chemical parameter means any measurable chemical characteristic of a substance including, but not limited to, pH, nitrogen, oxygen, carbon dioxide, water vapour.
- VOCs
– Volatile Organic Compounds (Benzene, Xylene, Tolueneetc.)
– Typically found in building materials, Cleaners, Solvents, Paintsetc.
– Eye, noise & throat irritation, headache and effects on target organs - Formaldehyde
– Very low Volatile Organic Compounds
– Used inpressed wood products, adhesives etc.
– Recognized as a major contribution in IAQ problems
- CO2
– Measured to access the adequacy of ventilation
– Indicator of inadequate ventilation
– Exposure to high level of Co2 can cause CNS effect - CO
– Inappropriately placed air intake or ventilated hole
– Smoking, vehicular exhaust
– Headache & nausea
– High concentration - Tobacco Smoke
– Frequent causes of complains for building occupants
– Burning of tobacco releases mixture of chemical including CO, NO2, formaldehyde, VOCs, and other gases
– Serious respiratory illnesses - Airborne Particles
– Particle Size typically defined as an aerodynamic diameter
– PM10 -< 10 u
– PM2.5 -< 2.5 u
– Photometer & Optical particle counters
– ASHRAE: PM 10 Limit –0.15 mg/m3 for 24 hours average
3. Biological Parameters
- Bioaerosols
– Airborne Particles -ACGIH
– Released from living organism
– Most concern -Bacterial, Viruses, Allergan’s, Mold, Fungus,
– Size: 0.1 –100 microns
– Bioaerosols –Dangerous Toxins (Mycotoxins) - Microorganism –Mold/Fungus
– Molds is significant role in IAQ
– Mold can grow on virtually any substances
– To prevent mold growth is to control moisture - Bioparticulates
– Animal dander –Allergic to humans.
– Pollen grains –Discharged from weeds, grasses & trees.
– Dust mite –Common cause of asthma & allergy. Survives well in mattresses, carpets, furniture & beddings.
