Universidade Federal de Santa Maria

Ci. e Nat., Santa Maria, v. 44, e44, 2022

DOI: 10.5902/2179460X67575

ISSN 2179-460X

Submitted: 09/06/2022 • Approved: 05/06/2022 • Published: 03/09/2022

1 INTRODUCTION.. 3

2 MATERIAL AND METHODS. 5

Environment

Levels of exhaled carbon monoxide in steakhouse workers in a town in the Brazilian Legal Amazon region

Níveis de monóxido de carbono exalado em trabalhadores de churrascarias em uma cidade da Amazônia Legal Brasileira

Igor Rian Bonelli de Oliveira ^I

Osvaldo Borges Pinto Júnior ^I

Silkiane Machado Capeleto ^I

Cristhiane Almeida Leite da Silva ^I

Walkiria Shimoya-Bittencourt ^I

^I Universidade de Cuiabá, Cuiabá, MT, Brazil

ABSTRACT

Occupational exposure to smoke from commercial kitchens such as steakhouses may be associated with an increase in the prevalence of respiratory symptoms and an acute reversible decrease in pulmonary functional capacity, and exposure to coal smoke is a risk factor for the development of respiratory diseases. The objetive of study was evaluate the levels of exhaled carbon monoxide (COex) and carboxyhemoglobin (COHb) in steakhouse workers. This is an observational, longitudinal and prospective study in the city of Cuiabá, Mato Grosso, Brazil. The total of 29 professionals working in steakhouses participated in the study. Data on socio-demographic characteristics, work environment characteristics, life habits and respiratory symptoms were extracted from questionnaires. COex and COHb levels were measured before exposure and every hour up to a 4 hour exposure period. Twenty-nine workers participated, with a predominance of females (55.2%), with a mean age of 36.40±11.49 years. It was observed that 18 (62%) of the workers had respiratory symptoms. COex and COHb levels were elevated after 4 hour exposure (p<0.05), but within acceptable parameters. COex and COHb levels are elevated in a short period of time to occupational exposure to steakhouse activities.

Keywords: Carbon Monoxide; Occupational groups; Occupational exposure; Occupational health; Air pollution

RESUMO

A exposição ocupacional à fumaça de cozinhas comerciais, como churrascarias, pode estar associada a um aumento na prevalência de sintomas respiratórios e uma diminuição reversível aguda capacidade funcional, sendo a exposição à fumaça do carvão um fator de risco para o desenvolvimento de doenças respiratórias. O objetivo do estudo foi avaliar os níveis de monóxido de carbono exalado (COex) e carboxihemoglobina (COHb) em trabalhadores de churrascaria. Trata-se de um estudo observacional, longitudinal e prospectivo realizado na cidade de Cuiabá, Mato Grosso, Brasil. Um total de 29 profissionais que trabalham em churrascarias participaram do estudo. Foram aplicados questionários com questões referentes a características sócio demográficas, características do ambiente de trabalho, hábitos de vida e sintomas respiratórios. Os níveis de COex e COHb foram medidos antes da exposição e a cada hora até um período de exposição de 4 horas. Dos vinte e nove trabalhadores que participaram, a predominância foi do sexo feminino (55,2%), com média de idade de 36,40±11,49 anos. Foi observado que 18 (62%) dos trabalhadores apresentavam sintomas respiratórios. Os níveis de COex e COHb estavam elevados após 4 horas de exposição (p<0,05), mas dentro dos parâmetros aceitáveis. Os níveis de COex e COHb são elevados em curto período de tempo de exposição ocupacional em atividades laborais de churrascaria.

Palavras-chave: Monóxido de carbono; Trabalhadores; Exposição ocupacional; Saúde do trabalhador; Poluição do ar.

1 INTRODUCTION

Restaurants is one of the most common companies in the world, employing millions of workers. However, these workers are at risk of exposure to various toxic compounds, and their health and safety is often neglected (BELANGER; TRICHE, 2009).

A very popular practice throughout the world is the use of charcoal for barbecuing indoors and outdoors (KABIR; KIM; YOO, 2011). Work activities in barbecue restaurant, contribute significantly to indoor air pollution, being a source of emissions of various toxic compounds combustion of charcoal, including varying sizes of particulate matter (PM), carbon monoxide (CO) and other air pollutants (HUANG; LEE; WU, 2016; NAEHER et al., 2007).

CO is a colorless, odorless and non-irritating gas, produced by the incomplete combustion of organic carbonaceous materials, also present in restaurant environments, being considered an extremely dangerous pollutant that gains attention due to its ability to harm human health. When inhaled in high concentrations it can render a person unconscious or even kill within minutes (BRUCE; PEREZ-PADILLA; ALBALAK, 2000; LACERDA; LEROUX; MORATA, 2005). Such toxicity can be explained when the gas competes with oxygen for hemoglobin, resulting in anoxia caused by the conversion of oxyhemoglobin to carboxyhemoglobin (COHb) (REHFUESS; BRUCE; SMITH, 2011).

It is known that almost half of the population depends on solid fuels for use in cooking, just like restaurant workers (BONJOUR et al., 2013) These fuels are typically burned in devices that are often inefficient and poorly ventilated, such as traditional open stoves and barbecue grills (NAEHER et al., 2007).

In addition, occupational and environmental pollution in the form of dust, fumes, vapors and toxic gases are risk factors for the development of respiratory disorders, lung cancer, increased prevalence of respiratory symptoms and acute reversible decrease in pulmonary functional capacity (FERNANDES; STELMACH; ALGRANTI, 2006; KURMI; LAM; AYRES, 2012; NEGHAB et al., 2017).

Due to the large number of polluting agents in the kitchens and in the barbecue environment, these workers are at high risk and consequently constitute one of the working classes that are occupationally exposed to develop these alterations (TANER; PELEY; PEKEY, 2013; BADYDA et al., 2018; WONG et al., 2011). This issue becomes more important when it comes to takes into account that these workers spend an average of six hours a day in this environment (MAHEMBE; MKOMA; KINAMBO, 2010).

Studies on air pollution and the health effects of the population have shown that, even when pollutants are below the levels determined by legislation, they are capable of causing effects on people's health (MARTINS et al., 2002; MORAES et al., 2010; AMÂNCIO; NASCIMENTO, 2012; GAVINIER; NASCIMENTO, 2014). Currently, the literature lacks knowledge about the effects of short-term exposure of the population using biomass fuel such as charcoal (DIETTE et al., 2012).

The aim of the present study was to evaluate the levels of exhaled carbon monoxide (COex) and carboxyhemoglobin (COHb) in steakhouses workers in a municipality in the Brazilian Legal Amazon region.

2 MATERIAL AND METHODS

An observational, longitudinal and prospective study was conducted involving steakhouses workers in the city of Cuiabá, Mato Grosso (MT), Brazil, from April 2018 to June 2018. The city's climate is classified as semi-humid tropical with maximum daily temperatures that oscillate between 30ºC and 36ºC with two well-defined seasons, one being dry (autumn-winter) and one rainy (spring-summer) (MARQUES et al., 2010; SANTOS et al., 2013)

Convenience sampling was performed among in steakhouses workers with air conditioning and refrigeration. This sampling was carried out according to convenience, because it was difficult to obtain authorization from the restaurants owners.

The study included worker aged 18 and 59 years who were working in steakhouses in the city of Cuiabá for at least 6 months. Pregnant women, workers with the presence of hemolytic and pulmonary diseases, using corticosteroids, practitioners of intense physical exercises and smokers were excluded from the study.

Data were collected in the employees' own work environment during their working hours. A data collection form was used with questions related to sociodemographic characteristics, the work environment and workers' life habits. British Medical Research Council based questionnaire was used to obtain information on respiratory symptoms. Thus, the following outcomes were assessed: presence of cough (yes/no), sputum (yes/no) and wheezing (yes/no). Subsequently, participants who responded positively to at least one of the items were classified as symptomatic. Workers who responded negatively to all assessed symptoms were classified as asymptomatic.

To ensure that workers did not have respiratory disease, lung function was assessed using spirometry, using a portable digital spirometer (model Datospir Micro C of brand Sibelmed®, year 2016), with graphic record in accordance with criteria of European Respiratory Society (ERS) e American Thoracic Society (ATS) (MILLER et al., 2005). Each participant performed three forced expiration maneuvers to obtain the ideal curve. The parameters analyzed were forced vital capacity (FVC), forced expiratory volume in the first second (FEV₁), forced expiratory flow at 25-75% (FEF_25-75) and the Tiffeneau index (FEV₁/FVC). The evaluation and classification of lung function were determined according to the criteria of studies of the Brazilian population (PEREIRA et al., 2007).

The levels of COex and COHb were assessed by the Micro CO Monoximeter (Micro Medical AS). To perform the maneuver, the worker remained seated, performing a maximum inspiration until the total lung capacity (TLC), followed by a 20-second apnea to balance blood CO levels with alveolar CO, slowly exhaling until residual volume (RV). Reference parameters of 6 ppm for COex (SANTOS et al., 2001), and 2.5% for COHb were used (SIQUEIRA et al.,1997). Values were obtained before the start of the workday, followed by four more evaluations, respectively, after 60, 120, 180 and 240 minutes of exposure smoke from barbecue grill.

The population characteristic was represented in tables with data distributed in frequency, proportion, mean and standard deviation. Analysis of variance was used for comparisons between levels of COex and COHb over the time of exposure followed by the Tukey test. The unpaired T test and Mann-Whitney test were used to verify the association between respiratory symptoms and the workers' personal and occupational characteristics. The level of significance established for the statistical tests was 5%.

This study was approved by the Research Ethics Committee of the University of Cuiabá under CAAE opinion: 66061316.5.0000.5165. All individuals received a free consent form that was previously signed to participate in the research.

3 results

A total of 36 individuals were evaluated, and of that amount, 9 were excluded according to the following criteria: smokers, changes in lung function, previous lung disease and withdrawal.

Participated in the study 27 non-smoking steakhouses workers, with a mean age of 36.60±11.62 years, predominantly female (59.2%) and non-white color (70.3%). It was observed that most were married (55.5%) and had completed high school (25.9%) (Table 1).

Table 1 – Distribution of demographic characteristics of steakhouse workers in the municipality of Cuiabá (MT), 2018

Characteristics	n=27
Age	36.60±11.62
Sex
Female	16 (59.2%)
Male	11 (40.7%)
Weight	71.8±11.14
BMI	25.9±3.43
Color
White	9 (33.3%)
Others	18 (66.6%)
Marital status
Married	15 (55.5%)
Not married	12 (44.4%)
Education
Without instruction	1 (3.7%)
Incomplete elementary school	4 (14.8%)
Complete elementary school	5 (18.5%)
Incomplete secondary education	5 (18.5%)
Complete secondary education	7 (25.9%)
Superior education incomplete	2 (7.4%)
Superior education complete	3 (11.1%)
Physical activity
Yes	8 (29.6%)
No	19 (70.3%)

Age: years; weight: kg; height: meters. BMI (body mass index): m/cm2

Fonte: Authors (2018)

The presence of respiratory symptoms was reported by 17 workers (62.9%). Regarding the characteristics of the work environment, 18 individuals (66.6%) belonged to functions with access to the kitchen/barbecue environment, 17 workers (62.9%) had knowledge about personal protective equipment (PPE) and only 9 (33.3%) reported using it. With regard to the daily workday, 19 workers (70.3%) worked within 8 hours (Table 2).

Table 2 – Occupational characteristics and respiratory symptoms of steakhouse workers. Cuiabá (MT), 2018

Characteristics	n=27
Respiratory symptoms
Symptomatic	17 (62.9%)
Asymptomatic	10 (37%)
Occupation from workers
Exposed environment (kitchen/barbecue grill)	18 (66.6%)
Unexposed environment (hall/buffet)	9 (33.3%)
Work time
Up until 8 hours	19 (70.3%)
More of 8 hours	8 (29.6%)
Knowledge about PPE
Yes	17 (62.9%)
No	10 (37%)
Use of PPE
Yes	9 (33.3%)
No	18 (66.6%)

PPE= personal protective equipment.

Fonte: Authors (2018)

The average COex before exposure was 1.66±0,96ppm and COHb was 0.27±0.14% with exhaled levels showing statistical difference after 1 hour of exposure (p<0.05), reaching final values of 6.07±2.49ppm for COex and COHb 0.97±0.39% (Table 3).

Table 3 - Exhaled carbon monoxide and carboxyhemoglobin levels of steakhouse workers in the municipality of Cuiabá (MT), 2018. Means with the same superscript letters do not differ significantly according to Tukey’s HSD post-hoc procedure

Exhaled carbon monoxide (ppm)		Carboxyhemoglobin (%)
Exposure time	Mean	Exposure time	Mean
Initial	1.66±0.96^a	Initial	0.27±0.14^a
1h	2.77±1.08^b	1h	0.44±0.17^b
2h	3.85±1.63^bc	2h	0.61±0.26^bc
3h	5.07±1.93^cd	3h	0.81±0.31^cd
4h	6.07±2.49^d	4h	0.97±0.39^d

Different Lowercase letters in columns indicate statistical difference by Tukey's test (p < 0.05).

Fonte: Authors (2018)

Regarding the association between respiratory symptoms and the personal and occupational characteristics of the research participants, no statistically significant differences were observed (Table 4).

Table 4 - Association between respiratory symptoms with the personal and occupational characteristics of steakhouse workers in the city of Cuiabá (MT), 2018

	General		Respiratory symptoms				P-value*
	General		Symptomatic (n=17)		Asymptomatic (n=10)		P-value*
	N	(%)	n	(%)	n	(%)
Sex							0.544
Male	16	(59.3)	11	(68.8)	5	(31.3)
Female	11	(40.7)	6	(54.5)	5	(45.5)
Age							0.458
Up until 30 anos	13	(48.1)	7	(53.8)	6	(46.2)
More of 30 anos	14	(51.9)	10	(71.4)	4	(28.6)
Color							0.668
White	9	(33.3)	5	(55.6)	4	(44.4)
Others	18	(66.7)	12	(66.7)	6	(33.3)
Marital status							0.347
Not married	12	(44.4)	9	(75.0)	3	(25.0)
Married	15	(55.6)	8	(53.3)	7	(46.7)
Use of PPE							0.820
Yes	9	(33.3)	6	(66.7)	3	(33.3)
No	18	(66.7)	11	(61.1)	7	(38.9)
Physical activity							0.979
Yes	8	(29.6)	5	(62.5)	3	(37.5)
No	19	(70.4)	12	(63.2)	7	(36.8)
Occupation							0.668
Exposed environment	18	(66.7)	12	(66.5)	6	(33.3)
Unexposed environment	9	(33.3)	5	(55.6)	4	(44.4)
Work time							0.147
Up until 8 horas	19	(70.4)	14	(73.7)	5	(26.3)

Mann-Whitney U test of independent samples.

Fonte: Authors (2018)

4 DISCUSSION

The use of firewood and charcoal for culinary purposes is used by about 3 billion people in developing countries (LANGBEIN; PETERS; VANCE, 2017). It is known that the combustion of charcoal, firewood, biomass fuel in stoves and open fires emit a substantial amount of carbon monoxide (CHEN; XING; HAN, 2009; VENKATARAMAN; RAO, 2001).

CO is a product of incomplete combustion of organic matter that, when combined with hemoglobin, forms COHb, altering the blood's ability to carry oxygen, resulting in several adverse health effects due to acute intoxication or chronic exposure (BAUER; PANNEN, 2009; CLAYTON et al., 2001).

In the present study, the average levels of COex and COHb by steakhouse workers showed a significant increase (p<0.05) after one hour of exposure, reaching a peak of 6.07ppm and 0.97% respectively for COex and COHb in 4 hours of exposure. Although the values increased over the measured exposure time, according to the literature, they were within the normal range (SANTOS et al., 2001; SIQUEIRA et al.,1997).

No other studies were found in which COex was measured before and after exposure directly at the workplace in steakhouse establishments, as well as the time of exposure during workers' hours. In addition, most research evaluates environmental measures for carbon monoxide, nicotine and lung function. Therefore, this study represents the first evidence what compare the levels of CO and COHb on a period of occupational exposure in steakhouses.

A study showed that COex had a stronger association with environmental exposure of CO in 2 hours compared to exposure in the last 4 and 6 hours. This weaker association of COex in the last 4 and 6 hours being due to the half-life of inhaled CO (LAWIN et al., 2017). The half-life of CO is 2 to 6 hours and, therefore, it is understandable that COex may better reflect the most recent exposure in 2 hours, making it a potential marker of acute exposure (UNDERNER; PEIFFER, 2010).

Considering this information and the lack of research that evaluates the exposure to COex over time and not only before and after the exposure, such as the difficulties in measuring it during the work, it was decided to measure this variable in 4 hours at 1-hour intervals.

In the investigation by Al et al., (2009) high levels of COHb (6.5±1.5%) were found in 40 employees of Kebab restaurants in Turkey. Another study was also found that assessed the levels of COHb conducted with 47 Turkish furnace operators, with a mean age of 35.3±3.9 years, with COHb levels of 4.5±1.5% (AL et al., 2012), being higher than the findings of the present study. Both surveys measured COHb levels before and after exposure to the oven, similar results that can be highlighted in a case study conducted with prolonged exposure to CO, which found 4.5% COHb in a 22 year old after 8 hours in contact with the outdoor grill (DIKME; DIKME; TOPACOGLU, 2018).

Although this study investigates individuals exposed to indoor pollutants, the COex and COHb values found are higher than some studies conducted in the same region. Salício et al., (2016) found an average of 2.69ppm of COex and 0.43% of COHb in elderly people who practice physical activity outdoors (external environment), findings that corroborate the study by Santos et al., (2001) who found mean of 2.5±2.1 ppm and 0.43±0.14% in non-smokers and ex-smokers, respectively.

CO levels in the body can be increased by direct inhalation of environmental gases, or by oxidative stress due to exposure to various pollutants (JOHNSON; KOZMA; COLOMBARI, 1999; DAWSON; SNYDER, 1994; WU; WANG, 2005). An important aspect to be taken into account to control other sources of exposure to carbon monoxide that could potentially influence COex and COHb measures was the participation of air-conditioned, ventilated and closed restaurants / steakhouses, that is, the people inside the establishment did not have contact with the external environment (sidewalks/streets). Thus, the high levels of COex and COHb found among the workers in this research can be justified due to the inhalation of the smoke from the barbecue.

The adverse effects of air pollution on human health have been recognized for decades and have shown that, even when pollutants are below the levels determined by legislation, they are capable of causing effects on people's health (MARTINS et al., 2002; MORAES et al., 2010; AMÂNCIO; NASCIMENTO, 2012; GAVINIER; NASCIMENTO, 2014). Recently, kitchen vapors have received greater public attention as an internal and external source of air pollution (WHO, 2019), and according to the World Health Organization (WHO), smoke from fuel during cooking kills about 4,3 million of people around the world each year, more deaths than caused by malaria, tuberculosis and human immunodeficiency viruses (HIV) combined making it one of the most lethal risks to environmental health (WHO, 2016; MARTIN et al., 2011).

Several studies have also linked the influence of exposure to carbon monoxide in various diseases. Quinn et al.,(2016) found an association between exposure to CO from wood stoves and increased blood pressure in pregnant women. In another study by Blaskievicz et al., (2020), it was found that exposure to CO and pollutants originating from the burning of biomass increases the activity of the disease in patients with systemic lupus erythematosus (SLE).

In addition, it is known that the large number of pollutants in kitchens are risk factors for the development of respiratory disorders and lung cancer, and employees of commercial kitchens are a risk group to develop these changes (FERNANDES; STELMACH; ALGRANTI, 2006; KURMI; LAM; AYRES, 2012; TANER; PELEY; PEKEY, 2013; BADYDA et al., 2018; WONG et al., 2011). Such an issue becomes more important when it is taken into account that they spend an average of six hours a day in this environment ((MAHEMBE; MKOMA; KINAMBO, 2010). Therefore, it is extremely important to develop preventive strategies and measures to promote workers' health in the context of commercial kitchens, seeking an improvement in production processes that make the worker's activity less unhealthy.

Regarding respiratory symptoms, a study conducted in Tanzania, in the East African region, which used a similar respiratory symptoms questionnaire, found that 68.9% of kitchen workers had respiratory symptoms resulting from exposure in this environment. For the authors, different types of fuels used in restaurants increase the risk of respiratory symptoms among workers ((MAHEMBE; MKOMA; KINAMBO, 2010). These results are similar to the present study, which noted that the majority of workers (62%) were also symptomatic. In an attempt to find out the reasons that may also justify the presence of respiratory symptoms in these workers, they were asked about the use of personal protective equipment (PPE). It was noted that 69% of workers reported that they do not use it. The high frequency of respiratory symptoms and the low institutional adherence to preventive measures such as this may influence the symptoms presented and in the future contribute to the appearance of respiratory disorders.

Despite the similarities mentioned above, in this study there were no significant associations between respiratory symptoms and the individual and occupational characteristics of barbecue restaurants workers. Since there were no associations, the high prevalence of symptomatic patients and the changes found in the levels of COex and COHb in workers may be associated with a higher emission of CO from the combustion of charcoal (CHEN; XING; HAN, 2009; VENKATARAMAN; RAO, 2001). The fact that reinforces the possibility of the influence of pollutants on exhaled levels is that the group of workers in this study was composed of active individuals, non-smokers, without changes in lung function previously assessed by spirometry and excluding those who used medicines, with previous illnesses and practitioners of intense physical exercises that could increase endogenous production and favor changes in COex ((SANTOS et al., 2001; JOHNSON; KOZMA; COLOMBARI, 1999).

This study had some limitations, such as the type of sample being of convenience due to the difficulty in obtaining authorization from the owners of the establishments, which limits the possibility of extrapolation to the totality of steakhouse workers. Other limitations were the sample size and the difficulty in carrying out the exams, due to the fact that the individuals are working hours and, therefore, have to stop their activities to participate. Despite the limitations, this study presented itself as an important guide for the health conditions of workers, considering that there are few studies that evaluated professionals in commercial kitchens exposed to smoke from charcoal. In this way, it contributes to the planning of more effective environmental health surveillance actions, minimizing the anthropic impacts and possible risks to the health of these workers.

5 CONCLUSIONS

The levels of exhaled carbon monoxide and carboxyhemoblogline in steakhouse workers are elevated in four hours of exposure and there was a high prevalence of reports of respiratory symptoms. Such findings can contribute to planning and surveillance strategies in environmental health, both for minimizing the possible health risks of these workers and for the anthropic impacts resulting from indoor air pollution.

REFERENCES

AL B, et al. The effect of chronic carbon-monoxide exposure on the peak expiratory flow values of grill-kebab chefs. Saudi Med J. v.30, n. 6, p:788-792, 2009.

AL B, et al. The effect of chronic carbon monoxide exposure on hs-CRP, CIM thickness and PEF in furnacemen. Turk J Biochem.v. 37, n.1, p:42-7, 2012. doi: 10.5505/tjb.2012.65365.

AMÂNCIO CT, NASCIMENTO LFC. Asthma and ambient pollutants: a time series study. Rev Assoc Med Bras. V. 58, n.3, p:302-7, 2012. doi: 10.1590/S0104-42302012000300009.

BADYDA AJ, et al. Inhalation Exposure to PM-Bound Polycyclic Aromatic Hydrocarbons Released from Barbecue Grills Powered by Gas, Lump Charcoal, and Charcoal Briquettes. Adv Exp Med Bio.v.1023, p11-27, 2018. doi: 10.1007/5584_2017_51.

BAUER I, PANNEN BHJ. Bench-to-bedside review: carbon monoxide--from mitochondrial poisoning to therapeutic use. Crit Care. v.13, n.4, p:220. 2009. doi: 10.1186/cc7887.

BELANGER K, TRICHE EW. Indoor combustion and asthma. Immunol Allergy Clin North Am. v.28, n.3, p:507-19, 2009. doi: 10.1016/j.iac.2008.03.011.

BLASKIEVICZ PH, et al. Atmospheric Pollution Exposure Increases Disease Activity of Systemic Lupus Erythematosus. Int J Environ Res Public Health.;v.17, n.6, p1984, 2020. doi: 10.3390/ijerph17061984.

BONJOUR S, et al. Solid fuel use for household cooking: country and regional estimates for 1980–2010. Environ Health Perspect.v.121, n.7, p:784-90, 2013. doi: 10.1289/ehp.1205987.

BRUCE N, PEREZ-PADILLA R, ALBALAK R. Indoor air pollution in developing countries: a major environmental and public health challenge. Bull World Health Organ.;v.78, n.9, p:1078-92. 2000.

CHEN LJ, XING L, HAN L. Renewable energy from agro-residues in China: Solid biofuels and biomass briquetting technology. Renew. Sustain Energy Rev.; v.13, n.9, p:2689-2695, 2009. doi: 10.1016/j.rser.2009.06.025.

CLAYTON CE, et al. Inhaled carbon monoxide and hyperoxic lung injury in rats. Am J Physiol Lung Cell Mol Physiol.;v.281, n.4, p:L949-L957, 2001. doi:10.1152/ajplung.2001.281.4.L949.

DAWSON TM, SNYDER SH. Gases as biological messengers: nitric oxide and carbon monoxide in the Brain. J Neurosci.; v.14, n.9, p:5147-5159, 1994. doi: 10.1523/JNEUROSCI.14-09-05147.1994.

DIETTE GB, et al. Obstructive lung disease and exposure to burning biomass fuel in the indoor environment. Glob Heart. v.7, n.3, p:265-70, 2012. doi: 10.1016/j.gheart.2012.06.016.

DIKME O, DIKME O, TOPACOGLU H. Carbon Monoxide Poisoning as a Result of an Open-Air Barbecue Activity. J Emerg Trauma Care.; v.3, n.3, p:1-3, 2018.

FERNANDES AL, STELMACH R, ALGRANTI E. Occupacional asthma. J Bras Pneumol.;v.32, n.1, p:27-34, 2006. doi: 10.1590/S1806-37132006000800006.

GAVINIER S, NASCIMENTO LFC. Air pollutants and hospital admissions due to stroke. Rev. Ambient. Água. V.9, n.3, p:390-401, 2014. doi: 10.4136/ambi-agua.1318.

HUANG HL, LEE WG, WU FS. Emissions of air pollutants from indoor charcoal barbecue. J Hazard Mater.;v.25, n.302, p:198-207, 2016. doi: 10.1016/j.jhazmat.2015.09.048

JOHNSON RA, KOZMA F, COLOMBARI E. Carbon monoxide: from toxin to endogenous modulator of cardiovascular functions. Braz J Med Biol Res. V.32, n.1, p:1-14,1999. doi:10.1590/s0100-879x1999000100001

KABIR E, KIM KH, YOON HO. Trace metal contents in barbeque (BBQ) charcoal products. J Hazard Mater.; v.185, n.(2-3), p:1418-24. 2011. doi: 10.1016/j.jhazmat.2010.10.064.

KURMI OP, LAM KBH, AYRES JG. Indoor air pollution and the lung in low-and medium-income countries. Eur Respir J. V.40, n.1, p:239-54, 2012. doi: 10.1183/09031936.00190211.

LACERDA A, LEROUX T, MORATA T. Ototoxic effects of carbon monoxide exposure: a review. Pro-fono Revista de Atualização Cientifica.; v.17, n.3, p:403-12, 2005. doi: 1590/S0104-56872005000300014.

LANGBEIN J, PETERS J, VANCE C. Outdoor cooking prevalence in developing countries and its implication for clean cooking policies. Environ. Res. Lett.;v.12, n.11, p:1-12, 2017. doi: 10.1088/1748-9326/aa8642.

LAWIN, H, et al. Exhaled carbon monoxide: a non-invasive biomarker of short-term exposure to outdoor air pollution. BMC Public Health.; v.17, n, 320, p:1-5, 2017. doi: 10.1186/s12889-017-4243-6.

MAHEMBE A, MKOMA SL, KINAMBO JL. Cooking fuels and respiratory symptoms in kitchen workers in Morogoro Municipality, Tanzania. Int J Biol Chem Sci.;v.4, n.4, p:976-983, 2010. doi: 10.4314/ijbcs.v4i4.63037

MARQUES R, et al. Composição química de águas de chuva em áreas tropicais continentais, Cuiabá-MT: aplicação do sistema clima urbano (S.C.U). Revista do Departamento de Geografia.;v.20, p:63-75, 2010. doi: 10.7154/RDG.2010.0020.0005

MARTIN WJ 2nd, et al. Public health. A major environmental cause of death. Science.; v.334, n.6053, p:180-181,2011. doi:10.1126/science.1213088.

MARTINS LC, et al. Poluição atmosférica e atendimentos por pneumonia e gripe em São Paulo, Brasil [Air pollution and emergency room visits due to pneumonia and influenza in São Paulo, Brazil]. Rev Saúde Pública.; v.36, n.1, p:88-94, 2002. doi: 0.1590/S0034-89102002000100014.

MILLER MR, et al. Standardisation of spirometry. Eur Respir J.; v.26, n.2, p:319-338, 2005. doi:10.1183/09031936.05.00034805.

MORAES ACL, et al. Wheezing in children and adolescents living next to a petrochemical plant in Rio Grande do Norte, Brazil. J Pediat.; v.86, n.4, p:337-44, 2010. doi: 10.2223/JPED.2020.

NAEHER LP, et al. Woodsmoke health effects: a review. Inhal Toxicol.;v.19, n.1, p:67-106, 2007. PMID: 17127644; doi: 10.1080/08958370600985875.

NEGHAB M, et al. Exposure to cooking fumes and acute reversible decrement in lung functional capacity. Int J Occup Environ Med.; v.8, n.4, p:207-16, 2017. doi: 10.15171/ijoem.2017.1100

PEREIRA CA, SATO T, RODRIGUES SC. New reference values for forced spirometry in white adults in Brazil. J Bras Pneumol.;v.33, n.4, p:397-406, 2007. doi:10.1590/s1806-37132007000400008.

QUINN AK, et al. Association of Carbon Monoxide exposure with blood pressure among pregnant women in rural Ghana: Evidence from GRAPHS. Int J Hyg Environ Health.; v.219, n.2, p:176-183, 2016.doi:10.1016/j.ijheh.2015.10.004.

REHFUESS E, BRUCE N, SMITH K. Solid Fuel Use: Health Effect. In: Nriagu JO (ed.) Encyclopedia of Environmental Health, v 5, pp. 150161 Burlington: Elsevier, 2011. Environmental Health. 2011;5:150161.

SALÍCIO MA, et al. Environmental variables and levels of exhaled carbon monoxide and carboxyhemoglobin in elderly people taking exercise. Cien Saude Colet.; v.21, n.4, p:1023-1032, 2016. doi:10.1590/1413-81232015214.14502015.

SANTOS FMM, et al. Análise da variação higrotérmica ocasionada pela influência da ocupação do solo na cidade de Cuiabá-MT. Rev. Elet. em Gestão, Educação e Tecnologia Ambiental.; v.9, n.9, p:1932-45, 2013.

SANTOS UP, et al. Emprego da determinação de monóxido de carbono no ar exalado para a detecção do consumo de tabaco [Use of breath carbon monoxide as an indicator of smoking status]. J Bras Pneumol.; v.27, n.5, p:231-36, 2001. doi: 10.1590/S0102-35862001000500001.

SIQUEIRA MEPB, et al. Valores de referência para carboxihemoglobina [Reference values for carboxyhemoglobin]. Rev. Saúde Pública.; v.31, n.6, p:618-23, 1997. doi: 10.1590/S0034-89101997000700010.

TANER S, PELEY B, PEKEY H. Fine particulate matter in the indoor air of barbeque restaurants: elemental compositions, sources and health risks. Sci Total Environ.;v.454, n. 55, p:79-87, 2013. doi: 10.1016 / j.scitotenv.2013.03.018.

UNDERNER M, PEIFFER G. Interpretation of exhaled CO levels in studies on smoking. Rev Mal Respir.; v.27, n.4, p:293–300, 2010. doi: 10.1016/j.rmr.2009.09.004.

VENKATARAMAN C, RAO GU. Emission Factors of Carbon Monoxide and Size-Resolved Aerosols from Biofuel Combustion. Environ Sci Technol.; v.35, n.10, p:2100-2107, 2001. doi: 10.1021/es001603d.

WONG TW, et al. Respiratory health and lung function in Chinese restaurant kitchen workers. Occup Environ Med.; v.68, n.10, p:746-52, 2011. doi: 10.1136/oem.2010.059378.

WORLD HEALTH ORGANIZATION. Household air pollution and health: WHO, 2018. Availabe from: Available from: https://www.who.int/news-room/fact-sheets/detail/household-air-pollution-and-health. Accessed in 2019 (Dec 28).

WORLD HEALTH ORGANIZATION. Public health, environmental and social determinants of health (PHE): WHO, 2016. Available from: http://www.who.int/phe/health_topics/outdoorair/databases. Accessed in 2017 (Feb 15).

WU L, WANG R. Carbon monoxide: endogenous production, physiological functions, and pharmacological applications. Pharmacol Rev.;v. 57, n.4, p:585-630, 2005. doi: 10.1124/pr.57.4.3.

Authorship contributions

1 – Igor Rian Bonelli de Oliveira

Professor at the Universidade de Cuiabá, Master in Environment and Health

https://orcid.org/0000-0001-7224-6884 • email: igorbonelli@yahoo.com.br

Contribution: Author of the master's thesis; responsible for writing the article.

2 – Osvaldo Borges Pinto Júnior

Professor at the Universidade de Cuiabá, Doctor in Tropical Agriculture

https://orcid.org/0000-0003-2653-5460 • email: osvaldo.borges@gmail.com

Contribution: Co-advisor of the master's thesis; responsible to data analysis and for reviewing of the article.

3 – Silkiane Machado Capeleto

Professor at the Universidade Estadual de Mato Grosso, Master in Environment and Health https://orcid.org//0000-0001-8661-756X • silk_machado@hotmail.com

Contribution: Co-author and responsible for writing the article.

4 – Cristhiane Almeida Leite da Silva

Professor at the Universidade de Cuiabá, Doctor in Pathology

https://orcid.org/0000-0002-9316-0382 • cristhianeleite@hotmail.com

Contribution: Co-advisor of the master's thesis; responsible for reviewing of the article.

5 – Walkiria Shimoya-Bittencourt (Corresponding Author)

Professor at the Universidade de Cuiabá, Doctor of Science

https://orcid.org/0000-0003-2350-8897 • wshimoya@yahoo.com.br

Contribution: Advisor of the master's thesis; responsible to the design of the research project and for reviewing of the article.

How to quote this article

SHIMOYA-BITTENCOURT, W; et al. Levels of exhaled carbon monoxide in steakhouse workers in a town in the Brazilian Legal Amazon region. Ciência e Natura, Santa Maria, v. 44, 2022. DOI: https://doi.org/ 10.5902/2179460X67575