Indoor Air Quality

Question 1

What are the factors affecting Indoor Air Quality (IAQ)?

Answer 1

1. Nature of ambient air
2. Infiltration rate or AER
3. Materials present
4. Activities (e.g cafe)

Question 2

What are some types of indoor air pollutants?

Answer 2

1. Pollutant gases (Ozone, NO2, SO2)
2. Particulate Matter (PM2.5, PM10)

Question 3

Where do Nitrogen Oxides come from?

Answer 3

1. High temperature combustion processes
2. Oxidation of nitrogen in air or fuel

Question 4

What is the source of NOx and what does it involve?

Answer 4

1. Road traffic
2. Power stations
3. Heating plants
4. Industrial Processes

Involves: NOx: NO and NO2

Question 5

What are some health effects of NO2?

Answer 5

1. Irritation of lungs
2. Lower resistance to respiratory infections (influenza)
3. In children: increased incidence of acute respiratory illness

Question 6

Factors: What is meant by nature of ambient air?

Answer 6

Outdoors around the building.
Exchanges takes place, indoor influence by outdoor air.

Question 7

What are some properties of Ozone?

Answer 7

1. Produced through photochemical process using UV radiation
2. Can only be produced outdoors
3. Indoor generation of ozone by:
   a) copying machines
   b) electrostatic precipitators
4. Ambient levels = 5 - 15 μg/m3
5. I/O usually smaller than 1

Question 8

Factors: What does the infiltration rate or AER depend on?

Answer 8

1. Site and design of building:
   a) tightly sealed
   b) insulated
   c) open design

Question 9

Factors: How do materials/polymers affect IAQ?

Answer 9

1. Produce formaldehyde (HCHO)
2. Cont. Supply HCHO
3. Sources of VOCs

Question 10

Where do VOCs come from in indoor air?

Answer 10

1. emitted from construction materials:
   a) wood composites
   b) insulating foams
   c) floor tiles
   d) carpet
   e) adhesives

Question 11

What VOCs are emitted from construction materials?

Answer 11

1. Aromatic & Aliphatic
2. VOCs (acetic & formic)
3. Formaldehyde
4. Chlorinated compounds
5. Acetone
6. Chloroform

Question 12

From what consumer products do VOCs come from?

Answer 12

1. Latex paint
2. cleaning agents
3. household solvents
4. detergents
5. waxes

Question 13

What does latex paint contain?

Answer 13

a) toluene
b) ethylbenzene
c) 2-propanol
d) butanone

Question 14

Where is formaldehyde present and under what concentrations?

Answer 14

10 - 200 μgm-3
1. resins (plywood)
2. wall papers
3. plastics
4. foams (as insulating materials)

Question 15

What activities occur within a building?

Answer 15

1. Combustion for heating and cooking
2. Cleaning:
   a) mechanical
   b) cleaning aids

Question 16

What gases are emitted from activities in a building and how?

Answer 16

1. CO2 - combustion of carbon-based fuels
2. CO
3. NO:
   a) wood or other biomass
   b) from N2 from combustion (eg burning of natural gas)

Question 17

What effect does hydroperoxy radical have on NO?

Answer 17

1. Contributes to oxidation of NO
2. Occurs due to break down of formaldehyde (UV-A from fluorescent lamps

Question 18

What is the outdoor and indoor concentration of HCHO?

Answer 18

Outdoor: <10 ppb
Indoor: 100 - 500 ppb

Question 19

What are the reactions occurring for the formation of .OH from HCHO?

Answer 19

1. HCHO -> HCO. + H.
2. H. + O2 -> HOO.
3. HCO. + O2 -> HOO. + CO2
4. HOO. + NO -> .OH + NO2

Question 20

What is the equation to calculate expected indoor concentration and what are the three scenarios?

Answer 20

Ri = keCi - keCo

1. Steady state: Ci = Co + Ri/ke
2. Outdoor conc. negligible: Ci = Ri/ke
3. No chemical produced indoors: Ci = Co