Content uploaded by Rusli Nordin
Author content
All content in this area was uploaded by Rusli Nordin
Content may be subject to copyright.
Assessment of indoor air quality and heat stress exposure in an automotive assembly plant 343
Assessment of indoor air quality and heat stress exposure in an
automotive assembly plant
Aziah Daud, Edimansyah Abdin, Azwan Aziz, Lin Naing and Rusli Nordin
X
Assessment of indoor air quality
and heat stress exposure in an
automotive assembly plant
Aziah Daud1, Edimansyah Abdin2*, Azwan Aziz1,
Lin Naing3 and Rusli Nordin4
1. Division of Occupational Medicine, Department of Community Medicine, School of
Medical Sciences, Health Campus, Universiti Sains Malaysia, Kelantan,
16150 Malaysia
2. (Correspondence author) Institute of Mental Health, Buangkok Green Medical Park,
10 Buangkok View,
Singapore 539747
3. Institute of Medicine, National University of Brunei Darussalam, Jalan Tungku Link,
Gadong BE 1410, Brunei Darussalam
4. Clinical School Johor Bahru, Tan Sri Jeffrey Cheah School of Medicine and Health
Sciences, Monash University, Johor Bahru, Johor, 80100 Malaysia
1. Introduction
Indoor air quality and heat exposure have become an important occupational health and
safety concern in the workplace. The indoor environment is important not only because of
the amount of time spent inside buildings but because there are indoor sources of pollution,
including, heating and cooking appliances, open fires, building and insulation materials,
furniture, fabrics and furnishings, glues, cleaning products, other consumer products, and
various biological sources, such as house dust mites, fungi, and bacteria. There is also the
inflow of polluted outdoor air through windows, evaporation of substances from water,
and, in some locations, infiltration of radon and other gases into the building from the
underlying soil and bedrock (Harrison, 2002).
Indoor air quality is the result of an intricate series of interactions involving many indoor
and outdoor ventilation, microbiological, toxicological, and physical systems (Jones, 2002).
Exposure to indoor toxicants can potentially lead to a variety of adverse health outcomes
(Bascom et al., 1995). The likelihood that an individual will become ill from the presence of a
contaminant depends upon factors such as the individual's sensitivity to that contaminant,
the contaminant concentration, the current state of their psychological and physical health
and the duration and frequency of exposure (Seltzer, 1997). Indoor air pollutants have the
potential to cause transient morbidity, disability, disease, and even death in extreme cases
16
Air Quality344
(Berglund et al., 1992). Recent research into these health outcomes has involved human,
animal, and in vitro studies (Maroni et al., 1995).
Heat stress is readily associated with high environmental temperatures and humidity. Many
work environments expose workers to extremely hot and humid conditions. Heat-related
illness is a problem for many types of workers: metal smelters, outdoor construction and
law enforcement workers, plastics manufacturing workers, landscaping and recreation
maintenance personnel, staff in warehouses without air conditioning, cooks and kitchen
workers, and athletes. A number of human factors contribute to a worker’s susceptibility to
heat stress, such as medical conditions, increasing age, overall level of fitness, presence of
other metabolically stressful illnesses, the use of certain medications, dehydration, alcohol
intake, and individual ability to acclimatize to extreme temperatures. Environmental factors
that can contribute to heat stress besides high ambient temperature are low convection
currents, high humidity, low evaporative loss, and high insulation levels around the body
(Ramphal, 2000).
Heat is a form of energy. It can be generated either endogenous or exogenous process
(Simon, 1994). Heat stress from safety and health point of view is physical hazards which
can cause health effects direct or indirect into certain industrial workers. Workers are
potentially exposed to heat will facing heat stress symptoms if they are not protected.
Environmental factors such as ambient temperature, relative humidity, radiant heat,
conduction and air velocity plays a major roles contribute to heat stress problems (OSHA,
1999).
2. Important of the Study
The automotive assembly plant in the automotive industry is well known to be a stressful
working environment. The automotive assembly plant is usually configured as three
successive shops in which the body is constructed, painted, and then assembled together
with all component parts into a finished vehicle (Figure 1). KvarnstrÖm (1997) reported that
an automotive assembly-line work is often perform in a workplace environment with
physical problems, such as noise, vibrations and dangerous machines that can be important
stress factors.
Fig. 1. Three stages of car manufacturing process
The automotive assembly plant is one of the main contributors to different types of
pollutants. For instance, waste from plastics, aluminum, cooper, rags, sandpapers, solvents
BODYSHOP PAINT SHOP ASSEMBLY
and paints can be generated. In particular, automotive painting processes generates, among
other issues, VOC emissions as paint solvents. Automotive painting and coating products
are formulated by using resins, pigments, volatile organic solvents, and chemical additives.
Unfortunately, the automotive coatings process ranks at the top of the emission volume
hierarchy. For this reason, knowing the pollution sources and their characteristics in this
sector is important for a proper prevention. Several initiatives have been developed
worldwide to promote occupational health and safety, and environmental protection
through regulations, code of practices, and guidelines for prevention (Esquer et al, 2009).
In an automotive assembly plant, exposure to indoor air pollutants and heat are probably
one of the most dangerous health hazards for the workers. Workers involved in auto body
repair are potentially exposed to a multitude of air contaminants. During structural repair,
activities such as sanding, grinding, and welding generate aerosols that are released into the
worker’s breathing zone. If the surface of the car being repaired contains toxic metals, such
as lead, cadmium, or chromium, exposure to these metals, is possible. Workers who paint
cars can be exposed to organic solvents, hardeners that may contain isocyanate resins and
pigments that may contain toxic components (NIOSH, 1993).
In Malaysia, IAQ has been recognized by the Department of Occupational Safety and Health
(DOSH) as a critical issue (DOSH, 2006). In order to ensure all workers are protected from
indoor air pollutants, the department has set forth a code of practice entitled “Code of
Practice on Indoor Quality” (DOSH, 2005). This code of practice is applied to all industries
in Malaysia including the automotive industry. One of the aims of the code was to establish
a set of maximum exposure limits for common indoor air contaminants, such as carbon
monoxide, carbon dioxide and respirable particulates (DOSH, 2005).
In Malaysia, although indoor air pollutants and heat exposure pose a risk to the worker’s
health, few studies have been conducted in this industry. This is a serious omission because
the automotive industry is a key player in the manufacturing sector, a high income
generating industry and a government-linked company in Malaysia. In 2004, Malaysia was
the largest producer of passenger cars in the Association of Southeast Asian Nations
(ASEAN), accounting for 24.4% of the total ASEAN motor vehicle production. For
commercial vehicles, Malaysia was the third largest producer, accounting for 11.0% of the
total ASEAN production (Prime Minister’s Department, 2005). Therefore, the aim of this
study was to determine the concentration of five common IAQ contaminants [carbon
dioxide (CO2), carbon monoxide (CO), respirable particulate matter (PM10), temperature
and relative humidity (RH)] and pattern of heat stress in the paint shop and body shop
sections of an automotive assembly plant in Malaysia.
3. Materials and Methods
3.1 Study design
A cross-sectional study of the two sections (paint and body shops) was conducted in 2005 at
an automotive industry plant located in Rawang, Selangor. During the assessment, workers
in paint shop section who were involved in study were worked in body preparation of car
before sending the body car into the primer booth (drying oven). They started their work
Assessment of indoor air quality and heat stress exposure in an automotive assembly plant 345
(Berglund et al., 1992). Recent research into these health outcomes has involved human,
animal, and in vitro studies (Maroni et al., 1995).
Heat stress is readily associated with high environmental temperatures and humidity. Many
work environments expose workers to extremely hot and humid conditions. Heat-related
illness is a problem for many types of workers: metal smelters, outdoor construction and
law enforcement workers, plastics manufacturing workers, landscaping and recreation
maintenance personnel, staff in warehouses without air conditioning, cooks and kitchen
workers, and athletes. A number of human factors contribute to a worker’s susceptibility to
heat stress, such as medical conditions, increasing age, overall level of fitness, presence of
other metabolically stressful illnesses, the use of certain medications, dehydration, alcohol
intake, and individual ability to acclimatize to extreme temperatures. Environmental factors
that can contribute to heat stress besides high ambient temperature are low convection
currents, high humidity, low evaporative loss, and high insulation levels around the body
(Ramphal, 2000).
Heat is a form of energy. It can be generated either endogenous or exogenous process
(Simon, 1994). Heat stress from safety and health point of view is physical hazards which
can cause health effects direct or indirect into certain industrial workers. Workers are
potentially exposed to heat will facing heat stress symptoms if they are not protected.
Environmental factors such as ambient temperature, relative humidity, radiant heat,
conduction and air velocity plays a major roles contribute to heat stress problems (OSHA,
1999).
2. Important of the Study
The automotive assembly plant in the automotive industry is well known to be a stressful
working environment. The automotive assembly plant is usually configured as three
successive shops in which the body is constructed, painted, and then assembled together
with all component parts into a finished vehicle (Figure 1). KvarnstrÖm (1997) reported that
an automotive assembly-line work is often perform in a workplace environment with
physical problems, such as noise, vibrations and dangerous machines that can be important
stress factors.
Fig. 1. Three stages of car manufacturing process
The automotive assembly plant is one of the main contributors to different types of
pollutants. For instance, waste from plastics, aluminum, cooper, rags, sandpapers, solvents
BODYSHOP PAINT SHOP ASSEMBLY
and paints can be generated. In particular, automotive painting processes generates, among
other issues, VOC emissions as paint solvents. Automotive painting and coating products
are formulated by using resins, pigments, volatile organic solvents, and chemical additives.
Unfortunately, the automotive coatings process ranks at the top of the emission volume
hierarchy. For this reason, knowing the pollution sources and their characteristics in this
sector is important for a proper prevention. Several initiatives have been developed
worldwide to promote occupational health and safety, and environmental protection
through regulations, code of practices, and guidelines for prevention (Esquer et al, 2009).
In an automotive assembly plant, exposure to indoor air pollutants and heat are probably
one of the most dangerous health hazards for the workers. Workers involved in auto body
repair are potentially exposed to a multitude of air contaminants. During structural repair,
activities such as sanding, grinding, and welding generate aerosols that are released into the
worker’s breathing zone. If the surface of the car being repaired contains toxic metals, such
as lead, cadmium, or chromium, exposure to these metals, is possible. Workers who paint
cars can be exposed to organic solvents, hardeners that may contain isocyanate resins and
pigments that may contain toxic components (NIOSH, 1993).
In Malaysia, IAQ has been recognized by the Department of Occupational Safety and Health
(DOSH) as a critical issue (DOSH, 2006). In order to ensure all workers are protected from
indoor air pollutants, the department has set forth a code of practice entitled “Code of
Practice on Indoor Quality” (DOSH, 2005). This code of practice is applied to all industries
in Malaysia including the automotive industry. One of the aims of the code was to establish
a set of maximum exposure limits for common indoor air contaminants, such as carbon
monoxide, carbon dioxide and respirable particulates (DOSH, 2005).
In Malaysia, although indoor air pollutants and heat exposure pose a risk to the worker’s
health, few studies have been conducted in this industry. This is a serious omission because
the automotive industry is a key player in the manufacturing sector, a high income
generating industry and a government-linked company in Malaysia. In 2004, Malaysia was
the largest producer of passenger cars in the Association of Southeast Asian Nations
(ASEAN), accounting for 24.4% of the total ASEAN motor vehicle production. For
commercial vehicles, Malaysia was the third largest producer, accounting for 11.0% of the
total ASEAN production (Prime Minister’s Department, 2005). Therefore, the aim of this
study was to determine the concentration of five common IAQ contaminants [carbon
dioxide (CO2), carbon monoxide (CO), respirable particulate matter (PM10), temperature
and relative humidity (RH)] and pattern of heat stress in the paint shop and body shop
sections of an automotive assembly plant in Malaysia.
3. Materials and Methods
3.1 Study design
A cross-sectional study of the two sections (paint and body shops) was conducted in 2005 at
an automotive industry plant located in Rawang, Selangor. During the assessment, workers
in paint shop section who were involved in study were worked in body preparation of car
before sending the body car into the primer booth (drying oven). They started their work
Air Quality346
from 8.00 a.m to 6.00 p.m. They had their morning break at 10.30 a.m to 10.45 a.m, lunch
break at 1.00 p.m to 2.00 p.m and evening break at 4.30 p.m to 4.14 p.m. Workers in body
shop section worked as welder (welding a car components using electronic spot gun
welder). Their work times were almost the same as workers in paint shop section.
3.2 Indoor air quality (IAQ) monitoring
After walk-through surveys of the sites, data collection of IAQ was done using direct-
reading instruments [the Q-TRAK™ Plus IAQ Monitor (TSI Inc, 2003a) and the DUST-
TRAK™ aerosol monitor (TSI Inc, 2003b)] during an eight hour work shift from 9:30 AM to
5:30 PM during painting and sanding operations. The instruments were located in both
sections (body and paint sections). The Q-TRAK™ Plus IAQ Monitor (TSI Inc, 2003a) was
used to record the CO, CO2, temperature and RH levels using a survey mode at one second
intervals. This mode was used to display the real-time readings of all parameters
simultaneously. Before sampling, the Q-TRAK™ Plus IAQ Monitor was calibrated for CO2
and CO by running a span gas with a known concentration and a zero gas through the
monitor by the local TSI distributor. The span gas concentrations for CO2 and CO were
1,000 ppm and 35 ppm, respectively. If measurements were not within specifications, the
instrument was recalibrated. The Q-TRAK™ Plus IAQ Monitor (TSI Inc, 2003a) uses a non-
dispersive infrared sensor for measuring CO2 concentration, an electrochemical sensor for
measuring CO concentration, a thermistor for measuring temperature, and a thin-film
capacitive element for measuring relative humidity (Ramachandran et al, 2002). A
DUSTTRAK ™ aerosol monitor (TSI Inc, 2003b) was used to measure PM10. The
DUSTTRAK ™ aerosol monitor measures PM10 at one minute intervals at a flow-rate of 1.7
l/minute. Before sampling, pre- and post-zero checks of the DUST-TRAK aerosol monitor
were carried out. The DUST-TRAK aerosol monitor is an optical instrument that detects
particles in the air matrix by optical scattering, using the optical diameter instead of the
aerodynamic diameter (Guo et al, 2004). The data was analyzed using TrakProTM v3.41
software.
3.3 Heat stress monitoring
In this study, heat stress monitor (Model: QUESTempo34 Thermal Environment Monitor,
Quest Technologies, USA) was used to measure the heat stress data. This data logging area
heat stress monitor measures four parameter: ambient or dry temperature (DB), natural wet
bulb temperature (WB), globe temperature (GB), and relative humidity (RH). The details of
definition and calculation of WBGT were published elsewhere (NIOSH 1986). This study
was used WBGT indoor (WBGTindoor) index as results. Both of sections were in enclosure
setting. Heat stress monitor was placed at the nearest position to the workers without
interrupted their movements and job tasking. This machine was set at 1.1 meter height in
stand position and supported by the standard photographic tripod. Tripod mounting is
recommended to get the unit away from anything that might block radiant heat or airflow.
Wet bulb reservoir is filled with distilled water. After adding water and placing the unit, all
parameter were stabilizing in surrounding area for 10 minutes. The machine was calibrated
before and after the measurements using calibration sensor module. After all procedure
done, measurement started and the machine recorded automatically in data logger. Heat
measurements took eight hours with interval one hour recorded all four parameter. All
setting was followed NIOSH (1986) standards. Eight hours exposure is a standard where
calculation based time-weighted average WBGT (TWA-WBGTindoor) with the equation
below:
n21
n n 2 2 11
t..........tt
t xWBGT .......... t x WBGT t x WBGT
(1)
where:
WBGT1 x t1 + WBGT2 x t2 + ……. + WBGTn x tn = WBGT values per hour
t1 + t2 + …. + tn = duration of exposure per hour
Heat monitoring started at 10.00 a.m and end-up at 5.00 p.m. The results of heat
measurements were printed directly from the machine and all parameter were analyzed.
The workplace which had WBGT indoor more than 28oC (>28 oC) was considered hot and
WBGT indoor less than 27.9 oC (≤27.9 oC) were considered normal (Granadillos, 1998).
3.4 Workload and work-rest regime evaluation
As described earlier, WBGT index can predict the severity of heat exposure. It is also can
showed suggested allowable work-rest regime for given workload. The American
Conference of Governmental Industrial Hygienists (ACGIH, U.S) published a standard
time-limited values (TLVs) for WBGT indices (ACGIH, 1992).
For the purpose of the study, workers who worked in paint shop section were considered in
acclimatized workers and workers in body shop section were considered in unacclimatized
workers. Acclimatized workers means the workers were exposure gradually to the hot
environment for 14 days or more (NIOSH, 1986) where else unacclimatized were verse versa
. Over all, workers in the paint shop and body shop sections were in moderate workload
and worked in 75% work / 25% rest in work-rest regime scales according to ACGIH
standards (ACGIH, 2001). Below is the table of Screening Criteria for Heat Stress Exposure
by ACGIH.
Work demand Light Moderate Heavy Very heavy
100% work 25.9 oC 27.5 oC 26.0 oC
75% work
25% rest
30.5 oC 28.5 oC 27.5 oC
50% work
50% rest
31.5 oC 29.5 oC 28.5 oC 27.5 oC
25% work
75% rest
32.5 oC 31.0 oC 30.0 oC 29.5 oC
Table 1. Screening criteria for heat stress exposure of acclimatized person
Assessment of indoor air quality and heat stress exposure in an automotive assembly plant 347
from 8.00 a.m to 6.00 p.m. They had their morning break at 10.30 a.m to 10.45 a.m, lunch
break at 1.00 p.m to 2.00 p.m and evening break at 4.30 p.m to 4.14 p.m. Workers in body
shop section worked as welder (welding a car components using electronic spot gun
welder). Their work times were almost the same as workers in paint shop section.
3.2 Indoor air quality (IAQ) monitoring
After walk-through surveys of the sites, data collection of IAQ was done using direct-
reading instruments [the Q-TRAK™ Plus IAQ Monitor (TSI Inc, 2003a) and the DUST-
TRAK™ aerosol monitor (TSI Inc, 2003b)] during an eight hour work shift from 9:30 AM to
5:30 PM during painting and sanding operations. The instruments were located in both
sections (body and paint sections). The Q-TRAK™ Plus IAQ Monitor (TSI Inc, 2003a) was
used to record the CO, CO2, temperature and RH levels using a survey mode at one second
intervals. This mode was used to display the real-time readings of all parameters
simultaneously. Before sampling, the Q-TRAK™ Plus IAQ Monitor was calibrated for CO2
and CO by running a span gas with a known concentration and a zero gas through the
monitor by the local TSI distributor. The span gas concentrations for CO2 and CO were
1,000 ppm and 35 ppm, respectively. If measurements were not within specifications, the
instrument was recalibrated. The Q-TRAK™ Plus IAQ Monitor (TSI Inc, 2003a) uses a non-
dispersive infrared sensor for measuring CO2 concentration, an electrochemical sensor for
measuring CO concentration, a thermistor for measuring temperature, and a thin-film
capacitive element for measuring relative humidity (Ramachandran et al, 2002). A
DUSTTRAK ™ aerosol monitor (TSI Inc, 2003b) was used to measure PM10. The
DUSTTRAK ™ aerosol monitor measures PM10 at one minute intervals at a flow-rate of 1.7
l/minute. Before sampling, pre- and post-zero checks of the DUST-TRAK aerosol monitor
were carried out. The DUST-TRAK aerosol monitor is an optical instrument that detects
particles in the air matrix by optical scattering, using the optical diameter instead of the
aerodynamic diameter (Guo et al, 2004). The data was analyzed using TrakProTM v3.41
software.
3.3 Heat stress monitoring
In this study, heat stress monitor (Model: QUESTempo34 Thermal Environment Monitor,
Quest Technologies, USA) was used to measure the heat stress data. This data logging area
heat stress monitor measures four parameter: ambient or dry temperature (DB), natural wet
bulb temperature (WB), globe temperature (GB), and relative humidity (RH). The details of
definition and calculation of WBGT were published elsewhere (NIOSH 1986). This study
was used WBGT indoor (WBGTindoor) index as results. Both of sections were in enclosure
setting. Heat stress monitor was placed at the nearest position to the workers without
interrupted their movements and job tasking. This machine was set at 1.1 meter height in
stand position and supported by the standard photographic tripod. Tripod mounting is
recommended to get the unit away from anything that might block radiant heat or airflow.
Wet bulb reservoir is filled with distilled water. After adding water and placing the unit, all
parameter were stabilizing in surrounding area for 10 minutes. The machine was calibrated
before and after the measurements using calibration sensor module. After all procedure
done, measurement started and the machine recorded automatically in data logger. Heat
measurements took eight hours with interval one hour recorded all four parameter. All
setting was followed NIOSH (1986) standards. Eight hours exposure is a standard where
calculation based time-weighted average WBGT (TWA-WBGTindoor) with the equation
below:
n21
n n 2 2 11
t..........tt
t xWBGT .......... t x WBGT t x WBGT
(1)
where:
WBGT1 x t1 + WBGT2 x t2 + ……. + WBGTn x tn = WBGT values per hour
t1 + t2 + …. + tn = duration of exposure per hour
Heat monitoring started at 10.00 a.m and end-up at 5.00 p.m. The results of heat
measurements were printed directly from the machine and all parameter were analyzed.
The workplace which had WBGT indoor more than 28oC (>28 oC) was considered hot and
WBGT indoor less than 27.9 oC (≤27.9 oC) were considered normal (Granadillos, 1998).
3.4 Workload and work-rest regime evaluation
As described earlier, WBGT index can predict the severity of heat exposure. It is also can
showed suggested allowable work-rest regime for given workload. The American
Conference of Governmental Industrial Hygienists (ACGIH, U.S) published a standard
time-limited values (TLVs) for WBGT indices (ACGIH, 1992).
For the purpose of the study, workers who worked in paint shop section were considered in
acclimatized workers and workers in body shop section were considered in unacclimatized
workers. Acclimatized workers means the workers were exposure gradually to the hot
environment for 14 days or more (NIOSH, 1986) where else unacclimatized were verse versa
. Over all, workers in the paint shop and body shop sections were in moderate workload
and worked in 75% work / 25% rest in work-rest regime scales according to ACGIH
standards (ACGIH, 2001). Below is the table of Screening Criteria for Heat Stress Exposure
by ACGIH.
Work demand Light Moderate Heavy Very heavy
100% work 25.9 oC 27.5 oC 26.0 oC
75% work
25% rest
30.5 oC 28.5 oC 27.5 oC
50% work
50% rest
31.5 oC 29.5 oC 28.5 oC 27.5 oC
25% work
75% rest
32.5 oC 31.0 oC 30.0 oC 29.5 oC
Table 1. Screening criteria for heat stress exposure of acclimatized person
Air Quality348
Work demand Light Moderate Heavy Very heavy
100% work 27.5 oC 25.0 oC 22.5 oC
75% work
25% rest
29.0 oC 26.5 oC 24.5 oC
50% work
50% rest
30.0 oC 28.0 oC 26.5 oC 25.0 oC
25% work
75% rest
31.0 oC 29.0 oC 28.0 oC 26.5 oC
Table 2. Screening criteria for heat stress exposure of unacclimatized person
4. Results
Parameters
DOSH
Standard*
in 8-TWA
Paint Shop Section Body Shop Section
Mean SD Min Max Mean SD Min Max
Temperature
(oc) 20-26 32.5
1.2 29.3
33.9
29.7
1.0
27.8 30.8
RH (%) 40-60 65.5
2.3 62.6
71.3
72.9
2.4
69.8 78.4
CO ppm 10 1.1
0.2 0.5
1.8
2.0
0.4
1.4 3.1
CO2 ppm C1000 252.8
30.7 204
360
252.5
28.3
204 339
PM10 mg/m3 0.15 0.4
0.1 0.2
1.6
0.4
0.1
0.2 2.4
Table 3. Descriptive summary of selected IAQ parameters in the paint shop section and
body shop section
Note: C is the ceiling limit, mg/m3 is milligrams per cubic meter of air at 250 Celsius and one
atmosphere pressure, ppm is parts of vapors or gas per million parts of contaminated air by volume,
8-TWA is time-weighted average for up to 8 hours/day
* (DOSH, 1996) and (DOSH, 2005)
4.1 IAQ Parameters
4.1.1 Temperature and RH
Fig 2 shows the average temperature and RH obtained in the paint and body shop sections.
The average temperature in the paint shop section was 32.5 +1.2ºC (29.7 - 33.9ºC and, in the
body shop section the average temperature was 29.7 +1.0ºC (27.8 - 30.8ºC). The relative
humidity in the body shop section ranged from 69.8 to 78.4% with an average of 72.9 +2.4%.
The RH in the paint shop section was 65.5+2.3% (62.6-71.3), higher than that in the body
shop. The temperature and RH of both sections exceeded those recommended by the DOSH
(Table 3).
4.1.2 CO
Fig 3 shows the concentrations of CO in the paint and body shop sections. The results show
that the concentration of CO in the body shop ranged from 1.4 to 3.1 with an average of 2.0
+0.4 ppm. In the paint shop, the concentration of CO ranged from 0.5 to 1.8 ppm with an
average of 1.1 +0.2 ppm. The average concentration of CO in the body shop was higher than
that in the paint shop. However, the concentrations of CO in both sections were within
DOSH standard limits (Table 3).
4.1.3 CO2
Fig 4 shows the concentrations of CO2 in the paint and body shop sections. The results show
the average concentration of CO2 in the paint shop was 252.8 +30.7 ppm, which was slightly
higher than in the body shop (252.5 + 28.3 ppm). The concentrations of CO2 in the paint and
body shop sections were 204-360 and 204-339 ppm, respectively. These concentrations were
within the DOSH standard limits (Table 3).
4.1.4 PM10
Fig 5 shows the concentrations of PM10 in the paint and body shop sections. The PM10
concentration in the paint shop section ranged from 0.2 to 1.6 ppm, with an average of 0.4 +
0.1 ppm, in the body shop section it was 0.4 + 0.1 ppm (0.2-2.4 ppm). The average PM10 in
both sections exceeded the DOSH standard limits (Table 3).
Fig. 2. Temperature and RH in the paint shop section (a) and body shop section (b)
Fig. 3. The concentration of CO in the paint shop (a) and body shop section (b)
Assessment of indoor air quality and heat stress exposure in an automotive assembly plant 349
Work demand Light Moderate Heavy Very heavy
100% work 27.5 oC 25.0 oC 22.5 oC
75% work
25% rest
29.0 oC 26.5 oC 24.5 oC
50% work
50% rest
30.0 oC 28.0 oC 26.5 oC 25.0 oC
25% work
75% rest
31.0 oC 29.0 oC 28.0 oC 26.5 oC
Table 2. Screening criteria for heat stress exposure of unacclimatized person
4. Results
Parameters
DOSH
Standard*
in 8-TWA
Paint Shop Section Body Shop Section
Mean
SD Min
Max
Mean
SD
Min Max
Temperature
(oc) 20-26 32.5
1.2 29.3
33.9
29.7
1.0
27.8 30.8
RH (%) 40-60 65.5
2.3 62.6
71.3
72.9
2.4
69.8 78.4
CO ppm 10 1.1
0.2 0.5
1.8
2.0
0.4
1.4 3.1
CO2 ppm C1000 252.8
30.7 204
360
252.5
28.3
204 339
PM10 mg/m3 0.15 0.4
0.1 0.2
1.6
0.4
0.1
0.2 2.4
Table 3. Descriptive summary of selected IAQ parameters in the paint shop section and
body shop section
Note: C is the ceiling limit, mg/m3 is milligrams per cubic meter of air at 250 Celsius and one
atmosphere pressure, ppm is parts of vapors or gas per million parts of contaminated air by volume,
8-TWA is time-weighted average for up to 8 hours/day
* (DOSH, 1996) and (DOSH, 2005)
4.1 IAQ Parameters
4.1.1 Temperature and RH
Fig 2 shows the average temperature and RH obtained in the paint and body shop sections.
The average temperature in the paint shop section was 32.5 +1.2ºC (29.7 - 33.9ºC and, in the
body shop section the average temperature was 29.7 +1.0ºC (27.8 - 30.8ºC). The relative
humidity in the body shop section ranged from 69.8 to 78.4% with an average of 72.9 +2.4%.
The RH in the paint shop section was 65.5+2.3% (62.6-71.3), higher than that in the body
shop. The temperature and RH of both sections exceeded those recommended by the DOSH
(Table 3).
4.1.2 CO
Fig 3 shows the concentrations of CO in the paint and body shop sections. The results show
that the concentration of CO in the body shop ranged from 1.4 to 3.1 with an average of 2.0
+0.4 ppm. In the paint shop, the concentration of CO ranged from 0.5 to 1.8 ppm with an
average of 1.1 +0.2 ppm. The average concentration of CO in the body shop was higher than
that in the paint shop. However, the concentrations of CO in both sections were within
DOSH standard limits (Table 3).
4.1.3 CO2
Fig 4 shows the concentrations of CO2 in the paint and body shop sections. The results show
the average concentration of CO2 in the paint shop was 252.8 +30.7 ppm, which was slightly
higher than in the body shop (252.5 + 28.3 ppm). The concentrations of CO2 in the paint and
body shop sections were 204-360 and 204-339 ppm, respectively. These concentrations were
within the DOSH standard limits (Table 3).
4.1.4 PM10
Fig 5 shows the concentrations of PM10 in the paint and body shop sections. The PM10
concentration in the paint shop section ranged from 0.2 to 1.6 ppm, with an average of 0.4 +
0.1 ppm, in the body shop section it was 0.4 + 0.1 ppm (0.2-2.4 ppm). The average PM10 in
both sections exceeded the DOSH standard limits (Table 3).
Fig. 2. Temperature and RH in the paint shop section (a) and body shop section (b)
Fig. 3. The concentration of CO in the paint shop (a) and body shop section (b)
Air Quality350
Fig. 4. Concentrations of CO2 in the paint shop (a) and body shop section (b)
Fig. 5. Concentrations of PM10 in the paint shop (a) and body shop section (b)
4.2 Heat stress
All result of paint shop and body shop section were showed in Table 4. As over all, the
study showed heat parameters in paint shop section (DB, WB and GB) were higher than
heat parameter in body shop section. The TWA-WBGTindoor of paint shop was higher (28.3
oC) than TWA-WBGTindoor of body shop (27.0 oC). The min of relative humidity (RH%) of the
paint shop was 48 RH% lower than RH% in body shop (55 RH%).
Heat parameters (min) Section
Paint shop Body shop
Dry temperature (DB)
(in oC)
34.3 32.2
Wet bulb temperature (WB)
(in oC)
25.5 24.8
Globe temperature (GB)
(in oC)
34.8 32.2
TWA-WBGTindoor
(in oC)
28.3 27.0
Relative humidity (RH%) 48 55
Table 3. Comparison of heat parameters in paint shop and body shop
Heat parameters (TWA-WBGTindoor, DB, WB and GB) in paint shop were increased higher
than heat parameters in body shop by time of measuring. By the way, both of the section
relatively showed all heat parameters were gradually increased by time (Figure 6).
Meanwhile, RH% in paint shop was gradually decreased lower than RH% in body shop
from start to end measuring (Figure 7). From the study, paint shop was considered “hot
area” (>28 oC) and body shop was considered “normal area” (≤27.9 oC).
In paint shop section, workers were worked in moderate workload and worked in 75%
work / 25%. From the TWA-WBGTindoor measured in paint shop section (28.3 oC), and
compared with screening criteria for heat exposure in Table 3 (75% work / 25%: moderate:
acclimatized: 28.5 oC), workers were not exposed to heat stress. This condition was similar in
workers in body shop when TWA-WBGTindoor measured was 27.0 oC (75% work / 25%:
moderate: unacclimatized: 26.5 oC).
Paintshop A
23
25
27
29
31
33
35
37
1000 1100 1200 1300 1400 1500 1600 1700
Time (hour)
Celcius (
o
C)
WBGTindoor
Twet bulb
Tdry bulb
Tglobe bulb
Bodyshop B
23
25
27
29
31
33
35
37
1000 1100 1200 1300 1400 1500 1600 1700
Time (hour)
Celcius (
o
C)
WBGTindoor
Twet bulb
Tdry bulb
Tglobe bulb
Fig. 6. The comparison heat parameters pattern in paint shop and body shop in 8 hours
measuring time
Assessment of indoor air quality and heat stress exposure in an automotive assembly plant 351
Fig. 4. Concentrations of CO2 in the paint shop (a) and body shop section (b)
Fig. 5. Concentrations of PM10 in the paint shop (a) and body shop section (b)
4.2 Heat stress
All result of paint shop and body shop section were showed in Table 4. As over all, the
study showed heat parameters in paint shop section (DB, WB and GB) were higher than
heat parameter in body shop section. The TWA-WBGTindoor of paint shop was higher (28.3
oC) than TWA-WBGTindoor of body shop (27.0 oC). The min of relative humidity (RH%) of the
paint shop was 48 RH% lower than RH% in body shop (55 RH%).
Heat parameters (min) Section
Paint shop Body shop
Dry temperature (DB)
(in oC)
34.3 32.2
Wet bulb temperature (WB)
(in oC)
25.5 24.8
Globe temperature (GB)
(in oC)
34.8 32.2
TWA-WBGTindoor
(in oC)
28.3 27.0
Relative humidity (RH%) 48 55
Table 3. Comparison of heat parameters in paint shop and body shop
Heat parameters (TWA-WBGTindoor, DB, WB and GB) in paint shop were increased higher
than heat parameters in body shop by time of measuring. By the way, both of the section
relatively showed all heat parameters were gradually increased by time (Figure 6).
Meanwhile, RH% in paint shop was gradually decreased lower than RH% in body shop
from start to end measuring (Figure 7). From the study, paint shop was considered “hot
area” (>28 oC) and body shop was considered “normal area” (≤27.9 oC).
In paint shop section, workers were worked in moderate workload and worked in 75%
work / 25%. From the TWA-WBGTindoor measured in paint shop section (28.3 oC), and
compared with screening criteria for heat exposure in Table 3 (75% work / 25%: moderate:
acclimatized: 28.5 oC), workers were not exposed to heat stress. This condition was similar in
workers in body shop when TWA-WBGTindoor measured was 27.0 oC (75% work / 25%:
moderate: unacclimatized: 26.5 oC).
Paintshop A
23
25
27
29
31
33
35
37
1000 1100 1200 1300 1400 1500 1600 1700
Time (hour)
Celcius (
o
C)
WBGTindoor
Twet bulb
Tdry bulb
Tglobe bulb
Bodyshop B
23
25
27
29
31
33
35
37
1000 1100 1200 1300 1400 1500 1600 1700
Time (hour)
Celcius (
o
C)
WBGTindoor
Twet bulb
Tdry bulb
Tglobe bulb
Fig. 6. The comparison heat parameters pattern in paint shop and body shop in 8 hours
measuring time
Air Quality352
Relative humidity in Paintshop A and Bodyshop B
35
40
45
50
55
60
65
70
75
80
1000 1100 1200 1300 1400 1500 1600 1700
Time (hour)
Relative Humidity (RH%
)
Paintshop A
Bodyshop B
Fig. 7. The comparison relative humidity (RH%) pattern in paint shop and body shop in 8
hours measuring time
5. Discussion and Conclusion
The present study was aim to determine the concentration of five common IAQ
contaminants [carbon dioxide (CO2), carbon monoxide (CO), respirable particulate matter
(PM10), temperature and relative humidity (RH)] and pattern of heat stress in the paint shop
and body shop sections of an automotive assembly plant in Malaysia. We found that the
temperature and RH in both sections exceeded the DOSH standard limits. The
recommended optimum comfort range for RH according to DOSH is 40% to 60%. Low
humidity can cause dryness of the eyes, nose and throat and may also increase the
frequency of static electricity shocks. The relative humidity in the body shop ranged from
69.8 to 78.4% with an average of 72.9 ± 2.4%. High humidity, above 80%, can be associated
with fatigue and “stuffiness” (DOSH, 1996).
We suggest the air-conditioning in this area should be monitored regularly. Humidity can
result in the growth of mould and dust mites within the area if allowed to become too high.
Rapid growth occurs when levels of humidity are above 60%, with a negative effect on
respiratory illnesses such as asthma. If the level of humidity becomes too low, below 30%,
this too can have adverse effects, with some people developing sore throats due to dryness
of the air (DOSH, 1996). In this study, the concentration of CO and CO2 were within the
DOSH standard limits.
Our study found that the mean PM10 levels in both sections exceeded the DOSH
recommendations at 0.15mg/m3. Inadequate ventilation of the sanders occurred during
sanding in the body shop which probably contributed to increased levels of PM10 in the
body shop. In the paint shop the high concentration of PM10 could be due to various
organic solvents and paint overspraying. Thus, respirators need to be used properly to
prevent worker exposure to air contaminants in the paint shop. Exhaust ventilation and
process isolation are commonly used controls for PM10 reduction. In conclusion, the
workers in the paint and body shop sections were exposed to high concentrations of RH,
temperature and PM10. Therefore, IAQ management programs, engineering controls,
training and education should be conducted in these sections to minimize IAQ problem
exposure.
In terms of heat stress monitoring, we found the heat environment in paint shop section was
hot compared with body shop section. The study carried by Aziz (2003) in automobile found
that, the TWA-WBGTindoor in paint shop was 29.2 oC and body shop was 24.7 oC. This
condition happens because of the work process itself. In paint shop as a process, the work
involved drying methods which painted car will have to dry in the oven booth before goes
to assembly shop. The building itself was enclosed, so that the heat generated by oven booth
will accumulated gradually through section. As a result, workers who worked nearest the
heat source were potentially exposed to the hot environments. Environmental factors such
as ambient temperature, relative humidity, radiant heat, conduction, air velocity and work
process can cause heat stress problems to the workers in hot workplaces (OSHA, 1999).
Paint shop was consider in hot (WBGT >28 oC) compared with body shop (WBGT ≤27.9 oC).
Its mean, the workers who worked in paint shop were potentially exposed to heat stress
problems compared workers in body shop (Ramsey, 1999). A paint shop was considered
hot-dry section (RH% >50) and body shop was considered hot-warm (%RH 50-70). A study
by Aziz (2003) showed workers in paint shop section were pruned to have heat stress
problems in hot-dry condition. The workers in body shop can also have heat stress
problems in hot-warm condition. If there is not air movement, the rates of sweat
evaporation on skin decreased if humidity increased. So, hot-warm can be stressful than
hot-dry condition (BOHS, 1990). According to standard of screening criteria for heat stress
exposure table 1 and table 2 by AGCIH, workers in both sections can worked in their work-
rest regime schedule without having heat stress problems. Work-rest regime is very
important in preventing heat stress in hot environment (OSHA, 1999). If the workers
worked in very hot environment with unsuitable work-rest regime, heat stress may high to
them.
Acclimatization program can increase the capability of heat tolerance to the workers who
worked in hot condition (Graveling et al, 1998). Acclimatized workers can prevent the heat
stress problems because their physiological system will responds immediately when they
were exposed to hot environment. Acclimatization program in 7-14 days can improve the
workers capability to the hot environment (Wildeboor and Camp, 1993). Therefore this
program should be implemented in hot area like paint shop section.
Heat stress monitoring in potential hot workplace should be monitor regularly. Thermal
indices like WBGT is the easiest way to predict the heat stress problem to the workers.
Although, this index is not giving more information on physiological changes in workers
who worked in hot environment, this is the effective way for early detection. The most
important system to tackle heat stress problems is heat stress management program. Beside,
the engineering control in workplace, training and education in heat stress management to
the workers can create the awareness among them when working in hot situation. Then,
heat stress problem can be reduced and safety and health of the workers will be protected.
Assessment of indoor air quality and heat stress exposure in an automotive assembly plant 353
Relative humidity in Paintshop A and Bodyshop B
35
40
45
50
55
60
65
70
75
80
1000 1100 1200 1300 1400 1500 1600 1700
Time (hour)
Relative Humidity (RH%
)
Paintshop A
Bodyshop B
Fig. 7. The comparison relative humidity (RH%) pattern in paint shop and body shop in 8
hours measuring time
5. Discussion and Conclusion
The present study was aim to determine the concentration of five common IAQ
contaminants [carbon dioxide (CO2), carbon monoxide (CO), respirable particulate matter
(PM10), temperature and relative humidity (RH)] and pattern of heat stress in the paint shop
and body shop sections of an automotive assembly plant in Malaysia. We found that the
temperature and RH in both sections exceeded the DOSH standard limits. The
recommended optimum comfort range for RH according to DOSH is 40% to 60%. Low
humidity can cause dryness of the eyes, nose and throat and may also increase the
frequency of static electricity shocks. The relative humidity in the body shop ranged from
69.8 to 78.4% with an average of 72.9 ± 2.4%. High humidity, above 80%, can be associated
with fatigue and “stuffiness” (DOSH, 1996).
We suggest the air-conditioning in this area should be monitored regularly. Humidity can
result in the growth of mould and dust mites within the area if allowed to become too high.
Rapid growth occurs when levels of humidity are above 60%, with a negative effect on
respiratory illnesses such as asthma. If the level of humidity becomes too low, below 30%,
this too can have adverse effects, with some people developing sore throats due to dryness
of the air (DOSH, 1996). In this study, the concentration of CO and CO2 were within the
DOSH standard limits.
Our study found that the mean PM10 levels in both sections exceeded the DOSH
recommendations at 0.15mg/m3. Inadequate ventilation of the sanders occurred during
sanding in the body shop which probably contributed to increased levels of PM10 in the
body shop. In the paint shop the high concentration of PM10 could be due to various
organic solvents and paint overspraying. Thus, respirators need to be used properly to
prevent worker exposure to air contaminants in the paint shop. Exhaust ventilation and
process isolation are commonly used controls for PM10 reduction. In conclusion, the
workers in the paint and body shop sections were exposed to high concentrations of RH,
temperature and PM10. Therefore, IAQ management programs, engineering controls,
training and education should be conducted in these sections to minimize IAQ problem
exposure.
In terms of heat stress monitoring, we found the heat environment in paint shop section was
hot compared with body shop section. The study carried by Aziz (2003) in automobile found
that, the TWA-WBGTindoor in paint shop was 29.2 oC and body shop was 24.7 oC. This
condition happens because of the work process itself. In paint shop as a process, the work
involved drying methods which painted car will have to dry in the oven booth before goes
to assembly shop. The building itself was enclosed, so that the heat generated by oven booth
will accumulated gradually through section. As a result, workers who worked nearest the
heat source were potentially exposed to the hot environments. Environmental factors such
as ambient temperature, relative humidity, radiant heat, conduction, air velocity and work
process can cause heat stress problems to the workers in hot workplaces (OSHA, 1999).
Paint shop was consider in hot (WBGT >28 oC) compared with body shop (WBGT ≤27.9 oC).
Its mean, the workers who worked in paint shop were potentially exposed to heat stress
problems compared workers in body shop (Ramsey, 1999). A paint shop was considered
hot-dry section (RH% >50) and body shop was considered hot-warm (%RH 50-70). A study
by Aziz (2003) showed workers in paint shop section were pruned to have heat stress
problems in hot-dry condition. The workers in body shop can also have heat stress
problems in hot-warm condition. If there is not air movement, the rates of sweat
evaporation on skin decreased if humidity increased. So, hot-warm can be stressful than
hot-dry condition (BOHS, 1990). According to standard of screening criteria for heat stress
exposure table 1 and table 2 by AGCIH, workers in both sections can worked in their work-
rest regime schedule without having heat stress problems. Work-rest regime is very
important in preventing heat stress in hot environment (OSHA, 1999). If the workers
worked in very hot environment with unsuitable work-rest regime, heat stress may high to
them.
Acclimatization program can increase the capability of heat tolerance to the workers who
worked in hot condition (Graveling et al, 1998). Acclimatized workers can prevent the heat
stress problems because their physiological system will responds immediately when they
were exposed to hot environment. Acclimatization program in 7-14 days can improve the
workers capability to the hot environment (Wildeboor and Camp, 1993). Therefore this
program should be implemented in hot area like paint shop section.
Heat stress monitoring in potential hot workplace should be monitor regularly. Thermal
indices like WBGT is the easiest way to predict the heat stress problem to the workers.
Although, this index is not giving more information on physiological changes in workers
who worked in hot environment, this is the effective way for early detection. The most
important system to tackle heat stress problems is heat stress management program. Beside,
the engineering control in workplace, training and education in heat stress management to
the workers can create the awareness among them when working in hot situation. Then,
heat stress problem can be reduced and safety and health of the workers will be protected.
Air Quality354
6. References
ACGIH. (1992). A manual of recommended practice, American Conference of Govermental
Industrial Hygienists
ACGIH. (2001). American Conference of Governmental Industrial Hygienists - Threshold Limits
Values and Biological Exposure Indices for 2001, American Conference of
Governmental Industrial Hygienists
Bascom, R. Kesavanathan, J. Swift, D.L. (1995). Human susceptibility to indoor
contaminants. Occupational Medicine 10 (1), 119-132.
BOHS (1990). The Thermal Environment. Technical Guide # 8, British Occupational Hygiene
Society
Berglund, B. Brunekreef, B. Knoppel, H. Lindvall, T. Maroni, M. L. Skov, P. (1992). Effects of
indoor air pollution on human health. Indoor Air 2(1), 2-25.
DOSH. (1996). Guidelines on occupational safety and health in the office. Putrajaya: Department
of Occupational Safety and Health, Ministry of Human Resource Malaysia.
DOSH. (2005). Code of practice of indoor air quality. Putrajaya: Department of Occupational
Safety and Health, Ministry of Human Resource Malaysia
DOSH. (2006). Annual report 2006. Putrajaya: Department of Occupational Safety and Health,
Ministry of Human Resource Malaysia
Esquer J, N. Elenesb, A. Zavala. (2009) Pollution Prevention in an Auto Assembly Plant in
Mexico. In. 2nd International Workshop | Advances in Cleaner Production. Key Elements
For A Sustainable World: Energy, Water And Climate Change. São Paulo – Brazil – May
20th-22nd – 2009
Granadillos, N. G. (1998). A study on the assessment of heat stress among Filipino workers.
Workshop on health and working conditions in South East Asia, Rangsit
University, Thailand
Graveling, R. A., L. A. Morris, et al. (1998). Working in hot conditions in mining: A literature
review. HSE Contract Reserach Report No. 10/1998. HSE, Institute of Occupational
Medicine
Guo, S.C.L. Chan, L.Y. (2004). Indoor air quality in ice skating rinks in Hong Kong. Environ
Res; 94: 327-35.
Harrison, P.T.C. (2002). Indoor air guidelines. OccupEnviron Med; 59: 73-4.
Jones, A.P. (2002). Indoor Air Quality. In. Air Pollution Science for the 21st Century. Edited by
J. Austin, P. Brimblecombe and W. Sturges. Elsevier Science Ltd.
Kvarnström, S. (1997). Stress prevention for blue-collar workers in assembly-line production, 1–32,
ILO, Geneva.
Maroni, M. Seifert, B. Lindvall, T. (1995). Indoor Air Quality - a Comprehensive Reference Book.
Elsevier, Amsterdam.
NIOSH. (1986). Criteria for a recommended standard...Occupational exposure to hot environments:
Revised criteria. Washington, D.C., National Institute for Occupational Safety and
Health
NIOSH. (1993). In-depth survey report: control technology for autobody repair and painting shops at
Team Chevrolet, Colorado Springs, Colorado. Cincinnati. US Department of Health and
Human Services, Centers for Disease Control, National Institute for Occupational
Safety and Health, DHHS-NIOSH.
OSHA. (1999). Heat stress: OSHA Technical Manual, U.S. Department of Labor.
Prime Minister’s Department. (2005). National automotive policy framework. Putrajaya: Prime
Minister’s Department.
Ramachandran, G. Adgate, J.L. Church, T.R. (2002). Indoor air quality in two urban
elementary schools: comfort parameters and microbial concentrations in air and
carpets. California: The 9th International Conference on Indoor Air Quality and Climate,
2002.
Ramphal, L. (2000). Heat stress in the workplace. BUMC PROCEEDINGS; 13:349–350
Ramsey, J. D. (1999). Limiting injury/illness at the hot workplace. Safety Science Monitor
Retrieved 27 July, 2005, from
http://www.monash.edu.au/muarc/ipso/vol3/oh1.pdf
Seltzer, J.M. (1997). Sources, concentrations, and assessment of indoor pollution. In:
Bardana, E.J., Montanaro, A. (Eds.), Indoor Air Pollution and Health. Marcel Dekker,
New York, pp. 11-60.
Simon, H.B. (1994) Hyperthermia and heatstroke. Hosp Pract. 29(8): p. 65-8, 73, 78-80.
TSI Inc. (2003a). Q-Trak Plus IAQ Monitor Model 8552/8554: Operation and service manual.
Shoreview, MN: TSI Inc,
TSI Inc. (2003b). DUSTTRAK Aerosol Monitor: operation and service manual Model 8520.
Shoreview, MN: TSC Inc,
Wildeboor, J. and J. Camp (1993). Heat stress: its effect and control. AAOHN J 41(6): 268-74
Assessment of indoor air quality and heat stress exposure in an automotive assembly plant 355
6. References
ACGIH. (1992). A manual of recommended practice, American Conference of Govermental
Industrial Hygienists
ACGIH. (2001). American Conference of Governmental Industrial Hygienists - Threshold Limits
Values and Biological Exposure Indices for 2001, American Conference of
Governmental Industrial Hygienists
Bascom, R. Kesavanathan, J. Swift, D.L. (1995). Human susceptibility to indoor
contaminants. Occupational Medicine 10 (1), 119-132.
BOHS (1990). The Thermal Environment. Technical Guide # 8, British Occupational Hygiene
Society
Berglund, B. Brunekreef, B. Knoppel, H. Lindvall, T. Maroni, M. L. Skov, P. (1992). Effects of
indoor air pollution on human health. Indoor Air 2(1), 2-25.
DOSH. (1996). Guidelines on occupational safety and health in the office. Putrajaya: Department
of Occupational Safety and Health, Ministry of Human Resource Malaysia.
DOSH. (2005). Code of practice of indoor air quality. Putrajaya: Department of Occupational
Safety and Health, Ministry of Human Resource Malaysia
DOSH. (2006). Annual report 2006. Putrajaya: Department of Occupational Safety and Health,
Ministry of Human Resource Malaysia
Esquer J, N. Elenesb, A. Zavala. (2009) Pollution Prevention in an Auto Assembly Plant in
Mexico. In. 2nd International Workshop | Advances in Cleaner Production. Key Elements
For A Sustainable World: Energy, Water And Climate Change. São Paulo – Brazil – May
20th-22nd – 2009
Granadillos, N. G. (1998). A study on the assessment of heat stress among Filipino workers.
Workshop on health and working conditions in South East Asia, Rangsit
University, Thailand
Graveling, R. A., L. A. Morris, et al. (1998). Working in hot conditions in mining: A literature
review. HSE Contract Reserach Report No. 10/1998. HSE, Institute of Occupational
Medicine
Guo, S.C.L. Chan, L.Y. (2004). Indoor air quality in ice skating rinks in Hong Kong. Environ
Res; 94: 327-35.
Harrison, P.T.C. (2002). Indoor air guidelines. OccupEnviron Med; 59: 73-4.
Jones, A.P. (2002). Indoor Air Quality. In. Air Pollution Science for the 21st Century. Edited by
J. Austin, P. Brimblecombe and W. Sturges. Elsevier Science Ltd.
Kvarnström, S. (1997). Stress prevention for blue-collar workers in assembly-line production, 1–32,
ILO, Geneva.
Maroni, M. Seifert, B. Lindvall, T. (1995). Indoor Air Quality - a Comprehensive Reference Book.
Elsevier, Amsterdam.
NIOSH. (1986). Criteria for a recommended standard...Occupational exposure to hot environments:
Revised criteria. Washington, D.C., National Institute for Occupational Safety and
Health
NIOSH. (1993). In-depth survey report: control technology for autobody repair and painting shops at
Team Chevrolet, Colorado Springs, Colorado. Cincinnati. US Department of Health and
Human Services, Centers for Disease Control, National Institute for Occupational
Safety and Health, DHHS-NIOSH.
OSHA. (1999). Heat stress: OSHA Technical Manual, U.S. Department of Labor.
Prime Minister’s Department. (2005). National automotive policy framework. Putrajaya: Prime
Minister’s Department.
Ramachandran, G. Adgate, J.L. Church, T.R. (2002). Indoor air quality in two urban
elementary schools: comfort parameters and microbial concentrations in air and
carpets. California: The 9th International Conference on Indoor Air Quality and Climate,
2002.
Ramphal, L. (2000). Heat stress in the workplace. BUMC PROCEEDINGS; 13:349–350
Ramsey, J. D. (1999). Limiting injury/illness at the hot workplace. Safety Science Monitor
Retrieved 27 July, 2005, from
http://www.monash.edu.au/muarc/ipso/vol3/oh1.pdf
Seltzer, J.M. (1997). Sources, concentrations, and assessment of indoor pollution. In:
Bardana, E.J., Montanaro, A. (Eds.), Indoor Air Pollution and Health. Marcel Dekker,
New York, pp. 11-60.
Simon, H.B. (1994) Hyperthermia and heatstroke. Hosp Pract. 29(8): p. 65-8, 73, 78-80.
TSI Inc. (2003a). Q-Trak Plus IAQ Monitor Model 8552/8554: Operation and service manual.
Shoreview, MN: TSI Inc,
TSI Inc. (2003b). DUSTTRAK Aerosol Monitor: operation and service manual Model 8520.
Shoreview, MN: TSC Inc,
Wildeboor, J. and J. Camp (1993). Heat stress: its effect and control. AAOHN J 41(6): 268-74
Air Quality356
