Indoor Air Quality

MOHD TALIB LATIF

School of Environmental and natural Resource SciencesFaculty of Science and TechnologyUniversity Kebangsaan Malaysia

Indoor Air QualityIndoor air quality (IAQ) is a term

referring to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants

Indoor Air PollutionThe National Health and Medical Research

Council (NHMRC- Australia) defines indoor air as air within a building occupied for at least one hour by people of varying states of health. This can include the office, classroom, transport facility, shopping centre, hospital and home.

Indoor air quality can be defined as the totality of attributes of indoor air that affect a person's health and well being.

Sick building syndrome Condition associated with

complaints of discomfort including headache; nausea; dizziness; dermatitis; eye, nose, throat, and respiratory irritation; coughing; difficulty concentrating; sensitivity to odors; muscle pain; and fatigue.

Sick building syndrome

The specific causes of the symptoms are often not known but sometimes are attributed to the effects of a combination of substances or individual susceptibility to low concentrations of contaminants.

The symptoms are associated with periods of occupancy and often disappear after the worker leaves the worksite.

Cause of SBSInadequate ventilation 52%Contamination from inside building

16%   Contamination from outside building

10% Microbial contamination  5% Contamination from building fabric 

4% Unknown sources 13%1

Thermal ComfortPersonal factors (health, psychology,

sociology & situational factors) Air temperature Mean radiant temperature Air movement / velocity (see wind chill

factor) Relative humidity (see also perspiration) Insulative clothing Activity levels.

THE IMPORTANT OF INDOOR AIR QUALITY

Indoor Air Quality Council-USAThe IAQ Council offers certifications in five disciplines

related to indoor air quality:

Indoor Environmental Consulting and InvestigationCouncil-certified Indoor Environmental Consultant

(CIEC) Council-certified Indoor Environmentalist (CIE)

Microbial Consulting and InvestigationCouncil-certified Microbial Consultant (CMC) Council-certified Microbial Investigator (CMI)

Microbial RemediationCouncil-certified Microbial Remediation

Supervisor (CMRS) Council-certified Microbial Remediator (CMR)

Indoor Air Quality AdministrationCouncil-certified Indoor Air Quality Manager

(CIAQM) Council-certified Microbial Claims Adjuster

(CMCA)

Residential Mold InspectionCouncil-certified Residential Mold Inspector

(CRMI)

Sources of Indoor Pollutants

Base on Specific BuildingCombustion activityFurnitureChemicalBuilding materialsFoodWaterSmoking activityOutdoor air pollution

Walkaround Inspection Potential Problem Areas Sample Collection

Contaminant Range Screening Method Validation Method

Bioaerosols 0-1,000 cfu/m3 Viable biological sampler

Carbon dioxide 0-2,000 ppm DT, IR Sampling bag, GC/TCD OSHA ID172

Carbon monoxide

2-50 ppm DT, meter Sampling bag, meter

Formaldehyde 0.04-1 ppm DT Coated XAD-2, GC/NPD OSHA-52

Nitric oxide 0-25 ppm DT TEA tube with oxidizer, DPP OSHA ID190

Nitrogen dioxide

0-5 ppm DT TEA-Molecular Sieve Tube, IC OSHA ID 182

Particulates 0-40,000 particles/cc

Light scattering meter  

Pesticides (See OSHA Chemical Information Manual)

Ozone 0-0.1 ppm DT, Chemiluminescent meter

 

Radon 4-200 pCi/L Radon Cartridge, Electrect

 

VOC's (See OSHA Chemical Information Manual)

GREEN BUILDING INDEX

http://www.greenbuildingindex.org/

Green Building Index (GBI)The Green Building Index (GBI) is Malaysia’s

industry recognised green rating tool for buildings to promote sustainability in the built environment and raise awareness among Developers, Architects, Engineers, Planners, Designers, Contractors and the Public about environmental issues and our responsibility to the future generations

What is DustDust consists of tiny solid particles

carried by air currents. These articles are formed by a disintegration or fracture process, such as grinding, crushing, or impact.

The Mine Safety and Health Administration (MSHA) defines dust as finely divided solids that may become airborne from the original state without any chemical or physical change other than fracture.

Occupational health point of view

Total Dust Inhalable Dust Respirable Dust

Total Dust

Total dust includes all airborne particles, regardless of their size or composition.

Inhalable DustThe EPA describes inhalable dust as that

size fraction of dust which enters the body, but is trapped in the nose, throat, and upper respiratory tract. The median aerodynamic diameter of this dust is about 10 µm.

Respirable DustRespirable dust refers to those dust particles

that are small enough to penetrate the nose and upper respiratory system and deep into the lungs.

Particles that penetrate deep into the respiratory system are generally beyond the body's natural clearance mechanisms of cilia and mucous and are more likely to be retained.

Fine mode

EC5%

Other19%

NH4+

11%

NO3-

4%

OC24%

SO42-

37%

Other OSHA DefinitionInhalable Particulate Mass

Dust particles having a 50% cut-point of 100 µm. These dust particles are hazardous when deposited anywhere in the respiratory tract.

Thoracic Particulate Mass Dust particles having a 50% cut-point of 10 µm. These dust

particles are hazardous when deposited anywhere in the lung airways and gas-exchange regions.

Respirable Particulate Mass Dust particles having a 50% cut-point of 4 µm. These dust

particles are hazardous when deposited anywhere in the gas-exchange regions.

Aerodynamic diameter

Percent

µm passing

(unit density spheres) selector

2.0 90

2.5 75

3.5 50

5.0 25

10.0 0

*MSHA – Mine Safety and Health Administration

INDOOR AIR SAMPLING(DOSH METHOD)

                                                                

Respirable Dust Sampling Head Total Dust Sampling Head

Respirable Dust Total Dust

Asbestos

GuidelineBase on Code of Practice on Indoor Air

Quality (DOSH 2005)

Indoor Air Contaminant

Eight-hour time weighted average airborne concentration

Unit ppm mg/m3

Carbon dioxide 1000

Carbon monoxide 10

Formaldehyde 0.1

Respirable particulate

0.15

Total Volatile organic compounds

3

OSHA (USA) Limit for Air Contaminantshttp://www.osha.gov/pls/oshaweb/

owadisp.show_document?p_table=STANDARDS&p_id=9992

Total dust...........| | ........ | 15 mg/m3| Respirable Fraction..| | ........ | 5 mg/m3 |

Further explanation by Young, J. M. (2008). Journal of Air Quality Atmosphere and Health.

Other Guideline

Agency

ASHAREAmerican Society of Heating, Air conditioning & Refrigeration Engineers, US

NIOSHNational Institute for Occupational Health and Safety, US

SIAQGSingapore Indoor Air Quality Guidelines

WHO World Health Organization

Parameter Air Quality Standard Organization

Carbon Monoxide 35 ppm / 40,000 µgm-3/ as 1 hour average EPA NPAAQS

9 ppm / 10,000 µgm-3/ as 8 hour average SIAQG

Carbon Dioxide Ventilation rate/air exchange rate to achieve carbon dioxidelevel below 1,000 ppm / 1800mg m-3/

ASHRAESIAQG

Total Volatile OrganicCompounds

4 ppm / 5mgm-3/ for total VOCs AIHA

3 ppm SIAQG

Ozone 0.12 ppm / 5µgm-3/ as 1 hour average EPANPAAQS

0.05 ppm / 100 µgm-3/ as 8 hour average WHOASHRAESIAQG

Respirable SuspendedParticulates

150 µgm-3 as 24 hour average50 µgm-3 as annual mean

EPANPAAQS

0.15 mgm-3 as 24 hour average SIAQG

Parameter Air Quality Standard Organization

Formaldehyde 1 ppm OSHA

0.4 ppm for indoor exposure ASHRAE

0.1 ppm / 120µgm-3 SIAQG

Temperature 22°C - 24°C ASHRAE

22.5°C - 25.5°C SIAQG

Relative Humidity 40% - 60% ASHRAE

70% SIAQG

Bacteria 500 CFU/ as a maximum value WHOAIHASIAQG

Air Movement 0.25m/s WHOSIAQG

Singapore

http://app2.nea.gov.sg/data/cmsresource/20090618385702933220.pdf

Lee, S. C., 2002

Hong Kong

Table 1: IAQ Objectives for Office Buildings and Public Places

Parameter Unit

8-hour average a Excellent Class Good Class

Room Temperature C

20 to < 25.5 b < 25.5 b

Relative Humidity %

40 to < 70 c < 70

Air movement m/s < 0.2 < 0.3

Carbon Dioxide (CO2) ppmv

< 800 d < 1,000 e

Carbon Monoxide (CO)

μg/m3 < 2,000 f < 10,000 g ppmv < 1.7 < 8.7

Respirable Suspended Particulates (PM10)

μg/m3 < 20 f < 180 h

Nitrogen Dioxide (NO2)

μg/m3 < 40 g < 150 h ppbv < 21 < 80

Ozone (O3) μg/m3 < 50 f < 120 g ppbv < 25 < 61

Formaldehyde (HCHO)

μg/m3 < 30 f < 100 f, g ppbv < 24 < 81

Total Volatile Organic Compounds (TVOC)

μg/m3

< 200 f < 600 f

ppbv < 87 < 261

Radon (Rn) Bq/m3 < 150 i < 200 f Airborne Bacteria

cfu/m3 < 500 j, k < 1,000 j, k

http://www.iaq.gov.hk/tables.htmlhttp://www.iaq.gov.hk

8 hrs!

EEFECT OF INDOOOR AIR QUALITY

Effect of Indoor Air PollutionSilicosis - Silicosis is a form of

pneumoconiosis caused by the dust of quartz and other silicates. The condition of the lungs is marked by nodular fibrosis (scarring of the lung tissue), resulting in shortness of breath. Silicosis is an irreversible disease; advanced stages are progressive even if the individual is removed from the exposure.

Black Lung - Black lung is a form of pneumoconiosis in which respirable coal dust particles accumulate in the lungs and darken the tissue. This disease is progressive. Although this disease is commonly known as black lung, its official name is coal worker's pneumoconiosis (CWP).

Asbestosis - Asbestosis is a form of pneumoconiosis caused by asbestos fibers. This disease is also irreversible.