Introduction developed and developing countries is air pollution,



Environmental health is the interaction between the
environment and human health and the resulting impacts on people’s health. One of
the key environmental risks to public health in developed and developing
countries is air pollution, both household (indoor) and ambient (outdoor). Acute
and long-term exposure to ambient air pollution have varying effects on human
health. Adverse effects from exposure lead to health outcomes requiring
hospital admissions, emergency room visits, chronic illness, and possibly death.
Various ambient air pollutants are linked with increasing the risk of morbidity
with regards to organ damage (e.g. kidney and liver), respiratory and
cardiovascular diseases, eye and skin irritation, hormone and immune functions,
neonatal development, and cancers.


World Health Organization (WHO) estimated that 2.78 million deaths across the
world in 2012 were attributed to ambient air pollution where 94% of the deaths were
due to non-communicable diseases in adults (e.g. lung cancer, ischemic heart
disease, stroke and chronic obstructive pulmonary diseases) and the remaining were
due to acute lower respiratory infection in children aged 5 and under. 1  These premature deaths could not be more
prevalent elsewhere than in the WHO Western Pacific Region (WPR) (Figure 1)
where 1.10 million (40%) of the total deaths occurred in low- and middle-income
countries that make up the WPR (e.g. Malaysia, China, Vietnam, Papua New Guinea
and Fijinorrahmah1 ).2 This statistic renders
ambient air pollution as one of the largest environmental health risk for the
population in this region.


Thenorrahmah2  major sectors that norrahmah3 contribute to ambient air pollution and
consequently have the primary intervention roles to reduce environmental risks
are transport and industry.3 Notwithstanding, the
mortality and burden of disease from ambient air pollution are largely
preventable through multi-sectoral efforts. The industry sector can play a
significant role in curbing air pollution through emission control and cleaner
industrial processes whereas improved monitoring and reporting of air pollution
and associated health trends by local and national agencies will allow tracking
of progress and the effectiveness of policies to reduce ambient air pollution.3,4 However, industry policies
that will drive intervention strategies on air pollution reduction is only
effective when they are founded upon the sector’s recognition of the reach of
environmental impacts and the associated public health risks from their
environmental releases, as well as the mechanisms that differentiate high
from low risk emissions.norrahmah4 


The global need for fossil fuel and consumer products from
petroleum ensures that the oil and gas industry continue to be one of the key
industrial sectors for years to come. However, the activities of the industry
are known to have ambient air quality implications through emissions of air
pollutants, notably greenhouse gases, photochemical air pollutants and their
precursors, and air toxics.5 Air emissions from these
facilities have been shown to be a determinant of the local air quality, proximal
community exposures to air pollutants have been much studied for association
with cancer, morbidity and mortality, and the associated health risks are one
of the highest concerns of the population. Rarely isolated from communities, it
is common for oil and gas facilities to operate near populated areas either
because they were built later near residential areas that have already been
established or people settle nearer the facilities as a corollary of the
economic, commercial and employment opportunities that the industry offer.  As a result, the air quality and health
impacts of oil and gas emissions are not only cumulative at the regional and
national levels but also directly experienced at very local levels.


Despite generalized trends, the exact nature of the
relationship between oil and gas emissions, population exposure and the level
of health risks from exposure to air pollutants is influenced by local-specific
variables, e.g. meteorological and terrain features that affect dispersion of
air pollutants, residential distance and population density from source of
emissions that affect the population at risk, and operational characteristics
of the oil and gas facilities that influence the pattern of air emissions. This
variability indicates a need to understand the local-specific context that
shapes this relationship, particularly in a region where ambient air pollution
has been identified as a critical environmental health threat.

Overview and Literature
Reviewnorrahmah5 Background on the oil and gas industry and air
emission sources


The oil and gas industry operates off 3 main sectors with diverse
activities that are successively linked with each other (Figure 2) and their primary
goal is to transform raw petroleum to commodity (bulk) chemicals (e.g.
gasoline, chlorine and sulfuric acid) and intermediate chemicals (e.g.
polyester films, polyvinyl chloride and phosphate fertilizer) for consumer
products.6 Facilities that emit air
pollutants can be found at each step in the chain of activities.


To achieve economic edge, petroleum companies may opt to
focus only on a set of activities (e.g. exploration and production) or perform
several successive activities in the chain called integration (e.g. exploration
and production, refining and petrochemical manufacturing). An integrated petroleum
complex, hence, could consist of various combination of facilities across
multiple sectors. An example of an integrated petroleum complex is in Kerteh,
Malaysia where the operational network comprised of upstream facilities (e.g. crude oil and natural gas
terminals), midstream facilities (e.g. gas processing plants and gas transmission
pipelines), and downstream facilities (e.g. oil refining and petrochemical
plants). Large integration is typically achieved by national oil and gas
companies (NOC) because of state policies regarding the petroleum sector, e.g.
industry participation, licensing and petroleum contracts.7


Air emission from oil
and gas facilities originates from numerous
activities during
production, transportation, refining, processing, distribution and marketing of petroleum which can be grouped
into several categories. Process and combustion
emissions occur as a result of the processes and activities employed to handle and treat petroleum
and other materials (e.g. acid gas removal, chemical
sweetening, catalytic cracking, use of incinerators, and flaring and venting), storage and
handling emissions occur when tanks release gas to maintain
equilibrium of pressure, temperature and concentration with ambient air (e.g. loading/unloading chemicals and vapor
recovery), fugitive emissions occur when hydrocarbons escape
through seals, valves and
flanges, and secondary emissions occur when hydrocarbons evaporate from polluted water, oily residuals,
sludges and wastes (e.g. waste water treatment and landfills).8
Hence, emissions can be released from point, volume or area sources.


Normal operation of an oil and gas facility typically
follows a periodically set production schedule with the aim to maximize
production targets. Often, the continuous normal operation of a facility is
subjected to disruptive or transient events that require the facility to
operate outside their normal operating conditions or to halt production (shutdown).
The transient events could be either planned or unplanned, involve one or more
units or the whole facility, and last for a short duration typically several
hours or days before normal production resumes. Examples of planned events
include minor and major maintenance activities, scaling back production load to
meet new production target, and catalyst change. Examples of unplanned
transient events include equipment malfunction, process upset such as catalyst or
reactor poisoning, and facility emergencies (e.g. fire and toxic gas release). Planned
and unplanned events regularly involve shutdown of equipment, several process
units, or the whole facility in order to manage the events and require the
facility to carry out ‘start up’ activities to get back in operation. Start-ups
and shutdowns may release higher air emissions than normal operation because of
process alignment activities, non-ideal process conditions (e.g. air-fuel ratio
to achieve complete combustion) and minimum/non-operation of control devices
before the operational system achieve normal, steady state. Throughout this
dissertation proposal, the term ‘transient events’ will be used to refer to
planned and unplanned events that results in partial or complete shutdown of a
facility and the ensuing start-up activities, whereas the term ‘excess
emissions’ will refer to air emissions consequent to shutdown and start-up

Air pollution and health concerns associated with oil and gas emission


A large number of studies showed
that the industry emits a wide range of air pollutants harmful to human health.
In addition to grouping air pollutants into
greenhouse gases, photochemical air pollutants and their precursors, and air
toxics, tThe
composition of air emissions from the oil and gas industry can be classified
into criteria pollutantspollutants (e.g. nitrogen dioxideoxides,
sulfur dioxide, and particulate matter), inorganic gases (, e.g. chlorine, ammonia, hydrogen cyanide, and hydrogen sulfide),
organic compounds, e.g. (methane, volatile organic
compounds (VOC), and polycyclic aromatic hydrocarbon (PAH)), and heavy metals, (e.g. arsenic, lead, and mercury). Air monitoring of oil and gas
emissions often found benzene, toluene, ethylbenzene and xylenes (BTEX),
1,3-butadiene, formaldehyde, n-hexane and hydrogen sulfide to be most abundant
and sometimes exceeding environmental and health-based standards.9–12

..add more
references on this.


A significant number of public health research
is devoted to studying the patterns of occurrence,
concentration levels and exposure to VOC, PAH, nitrogen dioxide, sulfur dioxide
and heavy metals.9–11,13–16 As
petroleum is made up of 50-98%
hydrocarbons composed
of alkanes
(paraffins), cycloalkanes
and aromatics
compounds,17 VOC and
PAH compounds are of great interest to
public health researchers for
their cancer and non-cancer health effects. More
than 75 VOC compounds can be retrieved from air monitoring samples
near oil and gas facilities9 and as many as 22 VOC carcinogens
have been found in air samples in one study18. Short term exposure to
ambient level PAH aggravates coronary heart diseases in people with the medical
condition whereas chronic effects include cancers of the lung, skin and bladder,
and DNA damage.19 Toxic Release Inventory (TRI)
reports from crude oil refinery, natural gas processing plants and
petrochemical facilities show that these facilities emit carcinogens associated
with cancers of the prostate, lung, bladder, kidney, breast and non-Hodgkin
lymphoma (NHL).20 ..add more references on this.



near oil and gas
facilities could be exposed
to the same chemicals that workers are exposed to although at much
lower concentration levels.21 Even at this low ambient levels,  communities residing near oil and gas
industry sites have been shown to be exposed to levels in excess of air quality
standards and in some cases, levels near the facilities were higher than the
levels in local cities.9,16,22,23 Exposure assessment of
ambient air pollutants from major industrial areas, including oil and gas
sites, seeks to identify the population at risk. A large number of studies
define or attempt to investigate exposed populations within 10 km and rarely
beyond 20 km of emissions sources.24 However, when industrial
production and processes are modified to reduce emissions, a marked improvement
in the local air quality and levels of nitrogen dioxide, sulfur dioxide, and
particulate matters were observed.25  This illustrates that oil and gas emission is
an important contributor to local air pollutant levels and the population at
risk resides reasonably close to emission sources.


Assuming that communities have no
direct control and are constantly exposed to air emissions, the health risks posed from community exposure could be higher compared to
occupational exposure for reasons such as the lack of systematic controls to limit exposures that are afforded in workplaces, lack of personal recovery periods and potentially long residential
duration. A
considerable amount of literature has been published on the health risk and
impacts of exposure to oil and gas air pollutants. A considerable amount of literature has been
published on the human
health impacts of
exposure to oil and gas air pollutants. These
studies showed that the industry emits a wide range of air pollutants harmful
to human health6–17 – with as many as 22 carcinogenic compounds found in
one study18.   Epidemiological studies have found exposed
communities to be at increased chances of respiratory
symptoms and cancers of the lungs and bladder, leukemia, and
allergic rhinitis26–30, as well as having greater
frequency of respiratory diseases and impaired lung function than those
unexposed.31–34 Health risk assessments of
communities near petrochemical sites found that the risks of cancer and
non-cancer health effects could be elevated compared to unexposed communities.35–38 In summary, there is a strong
evidence from studies worldwide that air emissions from oil and gas facilities contain
pollutants hazardous to public health and the associated health risks are of
concerns to the population living near the facilities.

Emissions during normal and non-normal operations


Emission standards are largely developed for permitting and
limiting emissions during normal operation and excess emissions from transient
events are often excluded from reporting or permitting requirements of state regulatory
agencies. However, significant progress through tighter enforcement of
compliance to the Clean Air Act has been made recently with the U.S. EPA’s
recognition that these exclusions results in facilities to ’emit pollutants
during such periods repeatedly and in quantities that could cause unacceptable
air pollution in nearby communities’.39 A study of an ethylene
facility found that start-up emissions could release huge quantities of
pollutants, namely 22,680 metric tonne (MT) of ethylene, 3.4 MT of nitrogen
oxides, 6.8 MT of hydrocarbons, and 45.4 MT of highly-reactive VOC.40 Lack of control of excess
emissions with significant consequences on population exposure was demonstrated
by a study where communities as far as 8 km from oil and gas flaring were
exposed to formaldehyde levels above the health-based standards for acute
effects.41 Despite the potentially
serious effects of transient events, it is common for excess emissions to be under-reported
or not reported altogether particularly when there is a lax in relevant
regulations. Obaid et al. (2017) reported that close to half of the facilities
that reported emissions data for normal operation and start-ups provided
similar data for shutdowns.42 X study found that …literature review on excess
emissions not reported ie focus on lack of reporting. Accordingly, emissions
data for transient events are less likely to be available in emission databases
and to be used in public health research on impacts of emissions.


Available studies on air quality
assessment of oil and gas facilities showed that the pattern of pollutant
release is varied between emissions under normal operation and transient
events. Predicted and modelled increases in emissions of  criteria pollutants, sulfur oxide, nitrogen
oxide, and VOC during transient events were higher than normal operation but
concentration levels may not be high enough to exceed air quality limits.42–44 A review of an LNG facility found that
nitrogen oxides emission were lower by at least 50% during start-up and
shutdown but particulate matter (PM10) emission was 18 times higher during
start-up and 110 times higher during shut-down compared to during normal
operation.42 In contrast, another study found that maximum
pollutant concentrations could be released in both scenarios.44  Therefore,
environmental health studies of the impact of oil and gas emissions should
consider evaluating both normal operation and transient events to determine
worst case scenario.


Gaps in Studies on Public Health Risks of Air
Emissions from Oil and Gas Facilities


Much is already known about typical air emissions from oil
and gas facilities and the resultant environmental health impacts. They are an
important determinant of the local air quality and pollutant levels can
contribute to violations of ambient standards. Epidemiology studies associate
emissions with various adverse health effects associated with acute and chronic
exposures. However, the approach taken by a large majority of research on the
public health impacts of oil and gas emissions has been cross-sectional in
nature, i.e. data are gathered at point(s) in time with the assumption that
they are characteristic of typical facility operation and emission mode. Most
studies in the field of public health are restricted to evaluating emissions
and air pollutants supposing that they are associated with normal operation. Studies have showed that transient
events produced sizeable quantity of air pollutants between 7-59% higher
emission rates compared to emissions during normal operation. These emissions
also led to transient impacts on local air quality and presumably higher acute
risks to public health.45–49 Despite this and other
evidences that point to the potential public health significance of transient
events emission, they are less investigated compared to normal emissions and
studies on public health risks associated with transient events are even
lacking. Previously described lack of reporting, unavailability of published data,
and inadequate emission standards regulating transient events emissions are
some of the causal factors that contribute to this gap in research. Another potential
limitation could be due to the exclusivity of the body of knowledge regarding oil
and gas and public health. While


bepublic health researchers are


that have been described previously The causal factors for
this gap in research can be attributed to the lack of reporting, unavailability
of data, and inconsistent emission standards regulating transient events
emissions that have been described previously. There are 2  


Research on the subject has been mostly restricted to
limited comparisons


In addition, there is a general lack of body of research
that simultaneously compare normal operation and transient events in the public
health domain despite projections of increasing global demand for petroleum fuels
and products. Therefore, there is an impetus for future studies of the impact
of oil and gas emissions on human health to evaluate both normal operation and
transient events to determine worst case scenario.


A substantial volume of air emissions, air pollution and
health risk assessment studies have been carried out for individual types of facilities
sited together (e.g. crude oil processing terminals or refineries and
petrochemical manufacturing complexes). However, there is a dearth of published
studies on air emissions from integrated petroleum operation which consists of
mixed facilities such as the site in Kereth, Malaysia. The lack of studies of
integrated petroleum facilities results in a lack of knowledge on their
combined emissions and attributable impacts on local air quality and public
health risks.


Despite the economic and environmental importance of the
petroleum industry in Malaysia, the
impacts of air emissions at current production rate on the populations at risk
in Malaysia have not been characterized. This results in a critical gap
in knowledge for current and future tracking of health risks as there is no
baseline information to compare with within the local context.


Despite the growing number of studies linking petroleum
emissions with air pollution, health risks and diseases, there is a lack of
similar studies in Malaysia.  In
contrast, there have been multiple studies in Thailand, Taiwan, and China 4,13,38–47 that gave valuable insight on the
interaction between the local petroleum industry and public health. The void in
knowledge demonstrates an immediate need for research in this area for several
reasons: first, the petroleum industry could be a significant contributor to
the local air pollution; second, villages and residential areas could be found
in close proximity to industrial sites; and third, long term effects due to air
pollution are often not part of routine health surveillance 50.  Results and recommendations from the proposed
study would potentially enlighten policy makers and drive informed decisions on
emission controls and community exposures.


The research to date has tended to focus on X (normal
emission) rather than Y (excess emissions).


Most studies in the field of X have only focused on ….

Questions and Specific Aimsnorrahmah6 


This dissertation intends to identify new knowledge that can
be evaluated on the characteristics of oil and gas emissions during normal
operations and transient events and the associated public health risks from
exposure to such emissions. The overall aim is to generate new data on
less-researched areas of the emissions of integrated oil and gas facilities in
order to advance knowledge of their environmental and public health impacts.
The long-term goal is to establish baseline data on the impacts of the industry
on health risks in order to support changes to public health policies and
interventions to protect the population at risk.


The following research questions (RQ) are relevant to this


RQ1: How does air emissions from oil and gas facilities at
an integrated petroleum site differ during normal operation and transient event
scenarios over the short (e.g. months) and long term (annual)?


RQ2: How does different emission scenarios impact the ground
level concentration of air pollutants and the population at risk? Are there any
distinguishing features that are drivers of pollutant levels (e.g. facilities)?


RQ3: What level of risks to acute and chronic health effects
should exposed population be concerned with as a result of exposure to oil and
gas emissions? How does the pattern of health risks compare when exposures are
brought about by normal operation versus by transient events? Which pollutants
drive the health risks?