Background: Petroleum has disastrous effects on human health, especially on the respiratory system due to its high accessibility and excellent absorption surface. Despite working at the petroleum station has serious health effects on respiratory system, in Ethiopia; there are no published data available to assess pulmonary function test among petrol filling workers.

Objective: To Assess Pulmonary Function Status of Petrol Filling Workers in Jimma Town, South West Ethiopia, 2018.

Methods: A comparative cross-sectional study was conducted with a total of 132 study participants (66 petrol fill workers and 66 controls) were employed in the study. An interview administered pre?tested structured questionnaire (BMRC) was used to collect data. Lung function was measured using a digital portable spirometer. Descriptive statistics, independent sample t-test and p value of less than 0.05 was considered significant

Result: the study revealed that the there is significant reduction (p<0.05) in FVC, FEV1, FEV1%, FEF25-75% and PEFR was found in the study group (Petrol fill workers) as compared to the controls. The prevalence of abnormal lung function is 37.9 and 15.2 among petrol fill workers and controls respectively.

 Conclusion: This study concluded that petrol fill workers are at greater risk of pulmonary function impairment. Creating awareness about proper utilization and effect of petroleum exposure.

Background
World Health Organization (WHO) defines healthy work place as a place where everyone works together to achieve an agreed vision for the health and well-being of workers and the surrounding community [1]. Petrol station is as a facility where fuel and lubricants for automobiles are sold [2].Petrol filling station workers are exposed to both petrol/diesel vapors and the vehicular exhaust [3,4].

Petroleum pump stations are not only an indispensable in modern technological society, but also lifeblood to modern appliances. However, they pose numerous risks and threats to employees and the environment. Anyone of the petrol stations presents a wide range of challenges to the health and safety of people and their environments [5]. Because  of  the  multitude  of hazards  in such workplaces and the overall lack of attention given to health and safety by  many employers, work-related accidents and  diseases continue  to  be serious   problems  in  all  parts  of  the  world [6].

Petroleum is a complex mixture of hydrocarbons that occurs in the earth in liquid, gaseous, or solid forms.  It is a naturally-occurring brown to black flammable liquid which was formed from the remains of tiny sea plants and animals that died millions of years ago.  It consists of hydrocarbons(aromatic,  saturated  and  unsaturated)  and  non-hydrocarbons (N, S, O2, vanadium and nickel [7–9].

Common cellular mechanism by which most air pollutants exert their adverse effects is their ability to act directly as prooxidants of lipids and proteins or as free radicals generators, promoting oxidative stress and the induction of inflammatory responses [10].The effect of vanadium compounds on the   function of alveolar macrophages may result in an impairment of the lung’s resistance to secondary bacterial infection, bronchitis and pneumonitis in human [11].

Petrol (or gasoline) and diesel fuel are a distillate of petroleum [12,13].About 95% of components in petrol vapor are aliphatic and acyclic compounds and less than 2% are aromatics [14–16]. However,  The  exact  mixture  of  which  types  of  hydrocarbons  are  present  in  petrol  depends  entirely  on  the  specific  sample  of  gasoline  (what type  of  oil  it  was  made from,  which company  refined  it  and  what additives were used [17]. Aromatic hydrocarbons are added to gasoline for maintaining high octane number and for best anti-knock properties. Refined petroleum products generally contain 2–3% benzene by volume [18].

Among the numerous constituents of petroleum products, gasoline constituents (benzene, toluene, ethyl benzene and xylene (BTEX) are designated as the most toxic compounds to humans [19]. Components of car-exhaust as a result of internal combustion of petrol, which are harmful, are CO2, NO2, SO2, benzene, formaldehyde and polycyclic hydrocarbons; these substances are known to produce harmful effects on health by interacting with molecules crucial to the biochemical or physiological processes of the human body [20].

In the occupational context, the lung is most exposed organ as toxic materials in the workplace usually gain entry to the body via an airborne route [21]. Occupational  diseases  in  gasoline-filling  workers  have been  recognized  for  many  years,  and  affect  workers  in  different  ways,  such diseases are still problems in all parts of the world [22]. It is a well-known fact that the polluted air causes ill effect on the health. Epidemiological studies have shown that a sudden increase in air pollution has often been associated with immediate increase in morbidity and mortality [23]. Globally, 3 million deaths were attributable to ambient air pollution in 2012 in which petroleum is one of the contributors to ambient air pollution. About 87 % of these deaths occur in low and middle income countries (LMICs), which represent 82 % of the world population. About 211 000 deaths occur in Sub-Saharan Africa [24]. Many studies have been  done  which  shows  the  effect  of  polluted environment  on  the  respiratory  tract [25].

Atmospheric concentration of gasoline vapor (approximately 2000 parts per million) is not safe when inhaled even for a brief period of time (seconds). During fuelling of vehicles, the concentration of gasoline vapor in the air is between 20 and 200 ppm [26].Several epidemiological studies on human populations exposed to petroleum vapors have shown that there is an increased incidence of diseases [27]. In  addition  to these  workers are  also  at  a  risk  of  inhaling  automobile  exhaust  fumes. The combined effects of the two may result in accelerated decline of lung function. High  ambient  air  concentrations  of solvents  and pollutants  had  well  defined  and marked  systemic  pulmonary  inflammatory response  with  decreased  forced  vital capacity(FVC), forced expiratory volume in the first second (FEV1), inspiratory and expiratory flow rates [10,28]. A study conducted in Zambia shows a higher prevalence of lung function impairment among fuel attendants (29.0%) than non-exposed participants (7.4%) with significant reduction parameters (FEV1, FVC and PEF) when compared with the non-exposed group (p values 0.004, 0.010 and 0.031, respectively [29].

Petrol pump workers spent 8-12 hours at their work place. Most of them are not using protective devices. This makes station workers to likely have grave ill effects on their health [30–33]. Despite working at petroleum station has such serious health effect on body systems especially on respiratory system, in Ethiopia, there is no published article conducted to assess the pulmonary function status of petrol filling workers. Hence, this study aims to evaluate the Pulmonary Function Status among Petrol Filling Workers in petroleum station.

Study Area and Period
The study was conducted in Jimma town from April 2 to May 2, 2018. There are 12 filling stations in the city which are owned by private companies.

Study design
Comparative cross-sectional study was employed

Population
Source Population:
Exposed Group: All petrol filling workers of Jimma town in 2018.

Control Group: All security guards were selected from Jimma town population.

Study Population:
Exposed Group: All petrol filling workers of Jimma town who was available during data collection period.

Control Group: non-smoking, age, sex, height, weight and educational status matched security guards were selected from Jimma town population.

Inclusion and Exclusion Criteria
Inclusion Criteria

• For study group: the person working in the petrol pump station for > 1year.
• For control group: non-smoking, age, sex, height, weight and educational status  matched security guards who have no history working in petroleum station or any other petrochemical industries were included in the study.

Exclusion Criteria
Subjects with history of diabetes mellitus, hypertension, pulmonary tuberculosis, asthma, chronic bronchitis, and those who were drug addicts, cigarette smokers and those who had undergone major abdominal or chest surgery were excluded from the study.

Sample Size Determination
Using double proportion formula the calculated sample size was 110. However, because of manageable sample size all petrol filling (81) workers working in 12 stations and the same number of (81) non- petrol filling workers were employed in the study. Therefore the final sample size will be 162.

Data Collection Procedures
Interview administered standardized questionnaire based on British Medical Research Council questionnaire was administered to each participant to obtain information on social demographic characteristics and use of personal protective equipment (PPE). Data was collected by qualified data collectors and supervised by the investigator.

Measurement of Respiratory System Variables
Spirometry
Using the digital spirometer Forced vital capacity (FVC), Forced Expiratory Volume in one second (FEV1), FEV1 /FVC ratio, FEF25-75 % and Peak Expiratory Flow Rate (PEFR) was measured.

The subjects were taken 10-15 minutes of rest before performing the Spirometry. Before performing the actual procedure, the participants were made to sit in upright position in a plastic chair with arm rest and feet in dependent position in order to avoid falling due to syncope. Participants were introduced to the instruments, and procedures were explained. Demonstration, handling, and use of instruments were explained. The Test was repeated three times and for each pulmonary parameter. The best result was considered for analysis. All pulmonary function tests were carried out at a fixed time of the day to minimize diurnal variation. All spirometer measurements were based on the American thoracic society guideline.

Study Variables
Dependent variables
Pulmonary function status (pulmonary function test)

Independent Variables

• Age, Sex, Educational status, Duration of work per years
• Duration of working hours per day, Use of personal protective device

Data Analysis Procedures
Data was entered in to EPI- data software and transferred to SPSS version 21(SPSS Inc, Chicago, USA) software for analysis. Descriptive statistics was used to summarize service year and anthropometric measurements of subjects.

Independent sample t-test was used to compare the mean respiratory scores of exposed and non- exposed groups.

Data Quality Management
The questionnaire was translated to Afaan Oromo (local language) and re translated back to English ,to keep consistency of question and administered to all control and exposed participant. Pre-test was conducted on (5% of study population) petroleum station workers of Agaro town. Based on the findings of the pre-test some modification and developments of the tool was done. Two days training was given to data collectors. Data collectors were instructed to check the completeness of each questionnaire whether each and every question is completely answered and also the supervisor rechecked the completeness of the questionnaire immediately after submission.

Ethical Consideration
Ethical clearance was obtained from Institute of Health Science Ethical Review committee of Jimma University to conduct the study and permission letter from fuel station owners was taken. Prior to data collection each study subject or participant was adequately informed about the purpose of the study and the importance of their participation to confirm willingness for participation. Participant’s confidentiality was maintained.

Pulmonary function status
An independent sample t-test was used to compare Spirometric measurement of pulmonary function (FVC, FEV1, FEV1%, FEF25-75% and PEFR) of exposed and non –exposed group. Accordingly, FVC, FEV1, FEV1%, PEFR& FEF25-75% were higher in control respondents than in exposed respondents and the mean difference was found to be statistically significant (p< 0.05) as shown in Table 1.

An increase in duration of exposure to volatile organic compounds results in decrease pulmonary function parameters. As presented in table below FVC (vs), FEV1 (vs), FEV1%, FEF - 25-75 %,( L/s) and PEFR (L/s) shows significant difference (p < 0.05).

Regarding their working hour’s pulmonary functions doesn’t show any significant difference among petrol fill workers. (Table 3)

The type of lung disorder mostly evident in exposed is restrictive. About 3(4.5%), 16(24.2%), 6(9.1%) and 4(6.1%), 4(6.1%) 2(3%) develop obstructive, restrictive and mixed type of lung disorder in petrol fill workers and controls respectively. FVC and FEV1 are affected in the above lung dis orders but FVC is more affected in restrictive and FEV1 more affected in obstructive.

The result of this study suggested decrease in pulmonary function in petrol fill workers when compared to controls. There is a high prevalence of lung function impairment among petrol fill workers (37.9) in comparison to controls (15.2). The prevalence lung function impairment among fuel station workers observed in this study is slightly higher than the prevalence which is observed in Ndola, Zambia (29%). This may be due to the minimum duration of service in this study is one year. However, 56.5% of the petrol attendants in Ndola, Zambia had been exposed for

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