Pa ge 1 Pa ge 19 American Journal of Environment and Climate (AJEC) Assessment of Common Ambient Air Pollutants and Respiratory Health Outcomes among Road Construction Workers in Imo State, Nigeria John Mark Bwala1, Agwu Nkwa Amadi1, Chimezie Christian Iwuala1, Ugo Uwadiako Enebeli2* Volume 4 Issue 3, Year 2025 ISSN: 2832-403X (Online) DOI: https://doi.org/10.54536/ajec.v4i3.5615 https://journals.e-palli.com/home/index.php/ajec Article Information ABSTRACT Received: July 07, 2025 Accepted: August 11, 2025 Published: September 01, 2025 Road construction workers are more likely to experience respiratory health problems because they are frequently exposed to air pollution. The purpose of this study was to assess the common ambient air pollutants and respiratory health outcomes among Nigerian road construction workers in Imo State. A cross-sectional study was conducted in Imo State, Nigeria, with 353 road construction workers from Imo State’s three senatorial zones selected using a multistage sampling technique. Gas meters placed at key points were used to measure the ambient concentrations of carbon monoxide (CO), sulphur dioxide (SO2), and suspended particulate matter (SPM) at construction sites. Respiratory symptoms and forced vital capacity (FVC) of the road construction workers were assessed by qualified health professionals. The mean CO, SO2, and SPM concentrations in Imo West were 182.40±6.41ppm, 516.24±55.03μg/m3, and 1956.22±30.75μg/m3 respectively; in Imo East, 185.34±6.46ppm, 518.26±55.12μg/m3, and 1960.17±30.79μg/m3 respectively; and in Imo North, 187.51±6.49ppm, 520.14±55.34μg/m3, and 1956.68±30.25μg/m3 respectively. In all zones, CO, SO2, and SPM levels significantly exceeded safe thresholds, according to the one- way ANOVA analysis (p<0.05) performed with SPSS. Among the most common respiratory health problems were coughing, 211 (59.77%); sneezing, 290(82.15%); catarrh, 79(22.38%); sore throat, 72(20.39%); asthma, 29(8.22%); short breath, 121(34.28%); pneumonia, 66(18.70%); headache, 133(37.68%); and wheezing, 170(48.16%). Mean FVC values were 2263.34±482.33 ml (Imo West), 2578.80±751.80 ml (Imo East), and 2382.78±610.42 ml (Imo North). To mitigate respiratory health risks, road construction workers are strongly recommended to consistently use personal protective equipment, particularly respiratory masks, during work activities. Keywords Ambient Air Pollutants, Imo State, Nigeria, Respiratory Health, Road Construction Workers 1 Department of Public Health, Federal University of Technology Owerri, Nigeria 2 Department of Community Medicine, Rhema University Nigeria, Aba, Nigeria * Corresponding author’s e-mail: doctorenebeli@yahoo.com INTRODUCTION Road construction workers’ respiratory health is seriously endangered by the exposure to hazardous pollutants such as dust, respirable crystalline silica (RCS), diesel exhaust fumes, and other toxic gases that come with road building activities (Boadu et al., 2023; Sarabi et al., 2025). Asthma, chronic bronchitis, and diminished lung function are among the respiratory disorders associated with these pollutants, which are produced by activities such as excavation, material handling, and heavy machinery operations (Kunar & Mandal, 2025; Landwehr et al., 2023). Road building is a crucial industry in Nigeria, especially in Imo State, yet little is known about the risks to employees’ occupational health (Bwala et al., 2025). Effective interventions and regulations to safeguard these workers are hampered by the absence of thorough data on exposure to air pollutants and the health effects of those exposures. By measuring the concentrations of common ambient air pollutants, including SPM, CO, and SO₂, at road building sites in Imo State, Nigeria, and analyzing their relationship to worker respiratory health effects, this study fills this knowledge gap. In order to reduce occupational health risks in this population, this study measured pollutant exposure, ascertained the frequency of respiratory symptoms, and presented data to support the development of policies and focused interventions. LITERATURE REVIEW Road and industrialization construction activities expose workers to hazardous compounds that might harm their respiratory health, making it a major source of ambient air pollution (Abdullahi et al., 2022; Hasan et al., 2021; Sarabi et al., 2025). Road construction workers’ occupational health risks are increased by the physically taxing nature of road construction as well as exposure to pollutants from materials and processes. Significant air pollutants are produced by operations including site clearance, earthworks, material manufacture, and driving heavy machinery on unpaved roads (Wang et al., 2025). According to a meta-analysis, the main occupational hazards causing respiratory disorders among road construction workers are dust, RCS, fumes, vapours, asbestos, fibres, and gases (Boadu et al., 2023). Excavation, tunnelling, demolition, sandblasting, grinding, masonry, rock drilling, road grading, milling, and wood processing (such as cutting, planing, and sanding) are among the tasks that expose workers to dust (Boadu et al., 2023). Handling fine particles of cement, fly ash, bricks, mortar, and sandstone, as well as mixing cement and concrete, are common operations that include RCS, a particularly dangerous pollutant (US Department of Labor Occupational Safety and Health Administration, 2024). Respiratory hazards are further increased by fumes, Pa ge 20 https://journals.e-palli.com/home/index.php/ajec Am. J. Environ. Clim. 4(3) 19-27, 2025 usually from welding, diesel exhaust, and asphalt (Kunar & Mandal, 2025). Road construction and repair require heavy machinery, most often diesel-powered. Chronic bronchitis and asthma are among the respiratory disorders linked to extended exposure to diesel exhaust fumes (Landwehr et al., 2023; Mo et al., 2022). Road construction workers, regrettably, frequently work long hours, increasing their exposure to dangerous materials and, as a result, the risk to their respiratory health (WHO, 2021). Road construction workers frequently work long shifts, which increases their exposure to these dangerous compounds and raises their risk of respiratory health problems issues (Boadu et al., 2023; Yasmeen & Hafeez, 2023). Despite this data, there is a paucity of studies in Imo State to assess the occupational respiratory risks of road transport workers; hence, this study aims to contribute to the development of targeted treatments and policies to mitigate the hazards to respiratory health of road construction workers in the region. MATERIALS AND METHODS Population of the Study The study population consisted of all road construction workers employed at construction sites across Imo State, Nigeria. Study Area This study was conducted among road construction workers aged 18 years and older in Imo State, located in the South-Eastern region of Nigeria. With a total area of roughly 5,100 km2, Imo State is located between the lower River Niger and the upper and middle Imo River. Its latitudes range from 4°45’N to 7°15’N and its longitudes from 6°50’E to 7°25’E. Sample Size Determination Cochran’s formula for cross-sectional research was used to determine the minimal sample size (Ogbeibu, 2014): n=(Z2 Pq)/d2 Where p is the percentage of construction workers having respiratory issues (35.5%) from a prior study (Isara et al., 2016), q is (1-p), d is the allowable margin of error (0.05), and n is the minimum sample size. ∴ n=(1.962 X 0.355 X 0.645)/0.052= 351.85= 352 A minimum sample size of 352 was established; in the end, 353 road construction workers participated in the survey. Sampling Technique The selection of the 353 participants was conducted using a multistage sampling technique. Imo State was divided into its three senatorial zones: Imo West, Imo East, and Imo North, in the initial phase. The major construction sites in each senatorial zone’s local government areas were randomly selected from a compiled list of all construction sites for the second stage. In the third stage, individual road construction workers at these sites were selected using simple random sampling. A total of 121, 122, and 110 workers were recruited from Imo West, Imo East, and Imo North, respectively. Inclusion criteria included being employed as a road construction worker, being aged 18 years or older, and having at least six months of experience in the profession. Exclusion criteria included non-road construction workers, those who did not provide consent, and workers with acute illnesses. Method of Data Collection Data was collected using the following instruments: • A structured questionnaire to capture demographic and health-related information. • A sphygmomanometer measures blood pressure. • A spirometer to assess forced vital capacity (FVC). • Gas meters to measure ambient levels of CO, SO₂, and SPM at strategic locations on construction sites. Method of Data Analysis Data was entered and analyzed using the Statistical Package for the Social Sciences (SPSS) software, version 23. Continuous and categorical variables were summarised using descriptive statistics, such as means and frequency distributions, respectively, and displayed in tabular form. With a 95% confidence interval and a significance level of 0.05, an analysis of variance (ANOVA) was used to assess variations in ambient air pollutant concentrations and the frequency of respiratory symptoms among the three senatorial zones. Ethical Consent Ethical approval was obtained from the Ethical Committee of the Department of Public Health, School of Health Technology, Federal University of Technology, Owerri, Imo State, Nigeria. Informed written consent was obtained from all participants prior to their inclusion in the study. RESULTS AND DISCUSSION A total of 353 male road construction workers from the three senatorial zones of Imo State, Nigeria (Imo East, Imo West, and Imo North), participated in this study. The data are summarized in Tables 1–7, where “n” denotes the number of participants and “%” represents the percentage. Age Demographic Profile of Road Construction Workers This study found that all the participants (road construction workers) were males. There were more 31–40-year-olds (33.43%) and 41-50-year-olds (27.76%), compared to the 18-30-year-olds (17.85%), as shown in Table 1. Road construction is a labour-intensive industry that involves heavy machinery, such as tractors, cement mixers, bulldozers, and excavators, which emit dust and gases, exposing workers to hazardous pollutants (Nikolay, 2018). The male majority in this study was comparable to earlier studies on road construction workers in Ghana’s Western North, Ashanti, and Ahafo regions (Yankson et al., 2023). The preponderance of men in construction may be due to the nature of the work, which involves hard labour such as removing rocks and dirt, constructing pavement, clearing vegetation, and building embankments. Pa ge 21 https://journals.e-palli.com/home/index.php/ajec Am. J. Environ. Clim. 4(3) 19-27, 2025 Awareness of Air Pollution Across Senatorial Zones Across the three senatorial zones, the majority of respondents strongly agreed with the following statements: road construction is a major source of dust (70.21%, n=248), dust can cause respiratory problems (93.01%, n=328), road construction materials contain harmful chemicals (87.81%, n=310), workers should consistently use personal protective equipment (PPE) (87.85%, n=310), rain and cold weather reduce dust levels (64.06%, n=226), and sunny weather promotes distant air movement (65.31%, n=231), as shown in Table 2. However, 0.53% (n=4) disagreed that road construction materials contain hazardous chemicals, and 5.33% (n=38) disagreed that road construction is a significant source of dust. Table 1: Age Demographic Profile of Road Construction Workers Age group (years) Imo West n(%) Imo East n(%) Imo North n(%) Total n(%) 18-30 18(5.1) 22(5.38) 23(6.51) 63(17.85) 31-40 43(12.18) 38(10.76) 37(10.48) 118(33.43) 41-50 35(9.92) 31(8.78) 32(9.07) 98(27.76) Above 50 25(7.08) 31(8.78) 18(5.10) 74(20.96) Table 2: Response of all subjects in Imo State on Air Pollution Awareness Information on Air Pollution Strongly Agree (%) Agree (%) Disagree (%) Strongly Disagree (%) GENERAL (ALL THE THREE ZONES) Road construction is a major source of dust 274(70.21) 27(7.03) 38(5.33) 0(0.00) Dust can cause respiratory health problems 303(93.01) 15(3.90) 0(0.00) 0(0.00) Road construction materials contain harmful chemicals 322(87.81) 38(9.64) 4(0.53) 0(0.00) Workers should always wear their PPE 311(87.85) 35(9.89) 0(0.00) 0(0.00) Rain and cold weather reduce dust 278(64.06) 76(33.45) 0(0.00) 0(0.00) Sunny weather promotes distant air movement 229(65.31) 40(11.30) 0(0.00) 0(0.00) IMO WEST Road construction is a major source of dust 97(82.45) 7(8.50) 4(1.50) 0(0.00) Dust can cause respiratory health problems 82(73.30) 5(5.00) 0(0.00) 0(0.00) Road construction materials contain harmful chemicals 95(85.57) 8(7.30) 0(0.00) 0(0.00) Workers should always wear their PPE 106(91.24) 10(9.17) 0(0.00) 0(0.00) Rain and cold weather reduce dust 85(77.55) 10(8.86) 0(0.00) 0(0.00) Sunny weather promotes distant air movement 94(86.90) 15(10.56) 0(0.00) 0(0.00) IMO EAST Road construction is a major source of dust 90(80.45) 7(9.50) 4(1.50) 0(0.00) Dust can cause respiratory health problems 93(88.30) 9(6.00) 0(0.00) 0(0.00) Road construction materials contain harmful chemicals 99(85.44) 7(6.35) 0(0.00) 0(0.00) Workers should always wear their PPE 91(84.24) 18(13.18) 0(0.00) 0(0.00) Rain and cold weather reduce dust 90(82.50) 15(12.86) 0(0.00) 0(0.00) Sunny weather promotes distant air movement 98(89.90) 13(10.02) 0(0.00) 0(0.00) IMO NORTH Road construction is a major source of dust 87(78.45) 10(9.11) 1(1.90) 0(0.00) Dust can cause respiratory health problems 96(90.28) 12(9.60) 0(0.00) 0(0.00) Road construction materials contain harmful chemicals 102(95.44) 4(6.35) 0(0.00) 0(0.00) Workers should always wear their PPE* 91(85.29) 16(12.10) 0(0.00) 0(0.00) Rain and cold weather reduce dust 100(92.92) 11(8.30) 0(0.00) 0(0.00) Sunny weather promotes distant air movement 88(79.43) 11(9.02) 0(0.00) 0(0.00) *PPE: Personal Protective Equipment Pa ge 22 https://journals.e-palli.com/home/index.php/ajec Am. J. Environ. Clim. 4(3) 19-27, 2025 Ambient Air Pollutant Levels Across Senatorial Zones The mean concentrations of ambient air pollutants at construction sites are presented in Table 3. Imo West had 1940.50 ± 24.15 μg/m³ of suspended particulate matter (SPM), Imo East had 1960.17 ± 30.79 μg/m³, and Imo North had 1956.68 ± 30.25 μg/m³. These variations were statistically significant (p<0.001). Significant differences (p<0.05) were also seen in the levels of carbon monoxide (CO), which were 183.50 ± 2.17 ppm in Imo West, 185.34 ± 6.46 ppm in Imo East, and 187.51 ± 6.49 ppm in Imo North. Sulfur Dioxide (SO₂) levels were 499.17 ± 42.92 μg/m³ in Imo West, 518.26 ± 55.12 μg/m³ in Imo East, and 520.14 ± 55.34 μg/m³ in Imo North, with significant differences (p<0.001). Dust (soil, gravel, wood, silica, non-silica mineral, and demolition dust) and diesel exhaust emissions from heavy-duty vehicles and stationary engines are common pollutants found at construction sites (Toronto Environmental Alliance, 2024). Carbon monoxide, hydrocarbons, sulphur and nitrogen compounds, and carbon dioxide are all present in diesel exhaust (Geldenhuys et al., 2022). The measurements made for this study showed that the concentrations of common ambient air pollutants from these common sources far exceeded the World Health Organization (WHO)’s acceptable criteria. Ambient SPM Levels Across Senatorial Zones The SPM levels, particularly PM₂.₅ and PM₁₀, were significantly elevated in this study (Table 3). Due to their deep penetration into the lungs, the elevated SPM levels raise the risk of lung disease, emphysema, and lung cancer (Cohen et al., 2005). PM₂.₅ is particularly dangerous as it contributes to asthma, cardiovascular disease, and early mortality due to its toxic components, which include heavy metals and carcinogenic organic compounds (Cohen et al., 2005). The study’s high SPM levels (1906– 1981 μg/m3) and the 158.07–1763.37 μg/m3 SPM range reported in Chinese building sites (Fang et al., 2025) both point to the urgent need for dust management measures. Table 3: Suspended Particulate Matter (SPM) Levels at Construction Sites across Senatorial Zones in Imo State GPS Location North GPS Location East SPM (μg/m3) IMO WEST 5.4882o 7.0175o 1930 5.4859o 7.0171o 1906 5.4840o 7.0180o 1934 5.4833o 7.0169o 1940 5.4851o 7.0173o 1977 5.4889o 7.0182o 1956 Mean ± Standard deviations: 1940.5 ± 24.15 P-value: <0.0001 IMO EAST 5.7822o 7.0390o 1942 5.7835o 7.0388o 1956 5.7830o 7.0398o 1923 5.7846o 7.0383o 1959 5.7892o 7.0381o 1960 5.7851o 7.0398o 1941 Mean ± Standard deviations: 1960.17 ± 30.79 P-value: 0.01 IMO NORTH 5.8191o 7.3411o 1945 5.8170o 7.3406o 1933 5.8186o 7.3424o 1909 5.8198o 7.3439o 1962 5.8182o 7.3401o 1981 5.8169o 7.3453o 1963 Mean ± Standard deviations: 1956.68 ± 30.25 P-value: <0.001 Pa ge 23 https://journals.e-palli.com/home/index.php/ajec Am. J. Environ. Clim. 4(3) 19-27, 2025 Ambient CO Levels Across Senatorial Zones Elevated CO levels portend major health risks because haemoglobin has a stronger affinity for CO than oxygen and forms carboxyhaemoglobin (HbCO), which reduces oxygen delivery to tissues and leads to hypoxia (Offiah et al., 2022). While chronic CO exposure can lead to melancholy, memory loss, and in extreme situations, central nervous system and heart poisoning or death, acute exposure can elicit symptoms including light-headedness, disorientation, headaches, and vertigo. Haemoglobin has a greater affinity for CO than oxygen, and forms carboxyhaemoglobin (HbCO), which lowers oxygen delivery to tissues and causes hypoxia (Offiah et al., 2022). This makes elevated CO levels a serious health risk. While chronic CO exposure can lead to melancholy, memory loss, and in extreme situations, central nervous system and heart poisoning or death, acute exposure can elicit symptoms including light-headedness, disorientation, headaches, and vertigo (Mishra & Krishnan, 2016). As seen in Table 4, the study’s measured CO levels (180–189 ppm) were much higher than the maximum CO range of 2.10–2.27 ppm recorded at another construction site in Lagos State, Nigeria, and well beyond the 100ppm threshold considered harmful to human health (Owolabi et al., 2024). These disparities could have been caused by differences in the various geographic locations’ seasonal weather patterns, human activities, and meteorological circumstances. Table 4: Carbon Monoxide (CO) Levels at Construction Sites across Senatorial Zones in Imo State GPS Location North GPS Location East CO (ppm) IMO WEST 5.4882o 7.0175o 183 5.4859o 7.0171o 181 5.4840o 7.0180o 183 5.4833o 7.0169o 182 5.4851o 7.0173o 187 5.4889o 7.0182o 185 Mean ± Standard deviations: 183.5 ± 2.17 P-value: <0.0001 IMO EAST 5.7822o 7.0390o 185 5.7835o 7.0388o 186 5.7830o 7.0398o 184 5.7846o 7.0383o 180 5.7892o 7.0381o 185 5.7851o 7.0398o 189 Mean ± Standard deviations: 185.34 ± 6.49 P-value: <0.0001 IMO NORTH 5.8191o 7.3411o 188 5.8170o 7.3406o 185 5.8186o 7.3424o 181 5.8198o 7.3439o 180 5.8182o 7.3401o 185 5.8169o 7.3453o 187 Mean ± Standard deviations: 187.51 ± 6.49 P-value: 0.02 Ambient SO₂ Levels Across Senatorial Zones This study’s ambient SO₂ levels were significantly higher (p<0.001) across senatorial zones, as shown in Table 5, which could have an impact on respiratory health. Although SO₂ is primarily absorbed by the upper airways’ mucous membranes, increased ventilation (e.g., during physical labour) can deliver higher doses to the lungs, causing bronchoconstriction, reduced lung function, and respiratory symptoms (Adetoun-Mustapha et al., 2011; Thacher et al., 2013). Long-term exposure to SO₂ has been linked to respiratory issues even at lower doses (0.4–3.0 ppm); however, attribution is made more difficult by confounding factors, including co-exposure to other pollutants (Rodney et al., Pa ge 24 https://journals.e-palli.com/home/index.php/ajec Am. J. Environ. Clim. 4(3) 19-27, 2025 2024). The high SO₂ values (499–520 μg/m³) in this study, which were higher than the average level of 17.95±7.44 µg/m³ recorded in India (Singh et al., 2023) suggest a significant risk to the respiratory health of Nigerian road construction workers. Table 5: Sulphur dioxide (SO2) Levels at Construction Sites across Senatorial Zones in Imo State GPS Location North GPS Location East SO2 (μg/m3) IMO WEST 5.4882o 7.0175o 460 5.4859o 7.0171o 559 5.4840o 7.0180o 453 5.4833o 7.0169o 477 5.4851o 7.0173o 510 5.4889o 7.0182o 536 Mean ± Standard deviation: 499.17 ± 42.92 P-value: <0.0001 IMO EAST 5.7822o 7.0390o 466 5.7835o 7.0388o 557 5.7846o 7.0383o 449 5.7892o 7.0381o 590 5.7851o 7.0398o 544 Mean ± Standard deviations: 518.26 ± 55.12 P-value <0.0001 IMO NORTH 5.8191o 7.3411o 449 5.8170o 7.3406o 578 5.8186o 7.3424o 461 5.8198o 7.3439o 480 5.8182o 7.3401o 503 5.8169o 7.3453o 522 Mean ± Standard deviations: 520.14 ± 55.34 P-value: <0.0001 Prevalence of Respiratory Health Problems Among Road Construction Workers The findings of similar studies, including Ekpenyong et al. and Isara et al., in Nigeria (Ekpenyong et al., 2012; Isara et al., 2016), and Mandal & Dutta (2022) in India which reported similar respiratory function impairment among Figure 1: Distribution of Respiratory Health Problems among Road Construction Workers in Imo State Pa ge 25 https://journals.e-palli.com/home/index.php/ajec Am. J. Environ. Clim. 4(3) 19-27, 2025 workers exposed to ambient air pollutants, are consistent with the high prevalence of symptoms like sneezing (82.15%, n=290), coughing (59.77%, n=211), wheezing (48.16%, n=170), headache (37.68%, n=133), shortness of breath (34.28%, n=121), catarrh (22.38%, n=79), sore throat (20.39%, n=72), pneumonia (18.70%, n=66), and asthma (8.22%, n=29) in this study (Figure 1). Comparing Respiratory Health Issues Among Senatorial Zones The distribution of respiratory symptoms among senatorial zones is shown in Table 6. Over half (56.50%, n=69) of Imo West, 58.50% (n=75) of Imo East, and 56.40% (n=62) of Imo North reported coughing. In Imo West, 76.45% (n=90), Imo East, 75.11% (n=88), and Imo North, 80.10% (n=85) of respondents reported sneezing. In Imo West, 21.47% (n=24), Imo East, 20.32% (n=26), and Imo North, 20.72% (n=28) of the population reported having diarrhoea. Headache was reported by 40.03% (n=45) in Imo West, 36.83% (n=44) in Imo East, and 42.14% (n=46) in Imo North. Wheezing was reported by 49.12% (n=54) in Imo West, 44.15% (n=52) in Imo East, and 53.45% (n=55) in Imo North. Table 6: Sulphur dioxide (SO2) Levels at Construction Sites across Senatorial Zones in Imo State Health Problem Imo West Imo East Imo North n % n % N % Cough 69 56.50 75 58.50 62 56.40 Sneezing 90 76.45 88 75.11 85 80.10 Catarrh 24 21.47 26 20.32 28 20.42 Sore throat 23 20.05 24 19.50 20 19.87 Asthma 8 6.49 10 7.32 7 5.45 Short breadth 40 35.80 42 37.59 33 29.23 Pneumonia 26 18.43 27 20.36 24 18.90 Headache 45 40.03 44 36.83 46 42.14 Wheezing 54 49.12 52 44.15 55 53.45 Comparison of Forced Vital Capacity Values Across Senatorial Zones Mean Forced Vital Capacity (FVC) values were 2263.34 ± 482.33 ml in Imo West, 2578.80 ± 751.80 ml in Imo East, and 2382.78 ± 610.42 ml in Imo North, as shown in Table 7. Seventeen workers had reduced FVC values of 0-1000ml according to spirometry results (Table 7), which may indicate respiratory impairment (Mason et al., 2010). The workers’ infrequent FVC monitoring exposes a gap in occupational health surveillance, as gradual lung function deterioration may not be detected until serious harm is already done (Lynch et al., 2021; Wallbanks et al., 2024). Table 7: Comparison of Forced Vital Capacity values of Road Construction Workers at different Senatorial zones Imo West Imo East Imo North FVC (ml) Total N % n % N % 0 – 1000 17 6 5.0 7 5.7 4 3.6 1001 – 2000 63 24 19.8 19 15.6 20 18.2 2001 – 3000 200 66 55.0 68 55.7 66 60.0 3001 – 4000 63 20 16.7 23 18.9 20 18.2 4001 – 5000 10 5 4.2 5 4.1 0 0.0 Total 353 121 100.00 122 100.00 110 100.00 Min (Max) 1250 (3270) 1190 (4118) 1885 (4491) Mean ± Std Dev 2263.3 ± 482.3 2578.8 ± 751.80 2382.8 ± 610.4 P-value P=0.17 CONCLUSIONS This study evaluated ambient air pollutant levels at road construction sites in Imo State, Nigeria, and their impact on workers’ respiratory health. The key findings were that road construction workers are exposed to high levels of ambient air pollutants (CO, SO₂, SPM) exceeding WHO safe limits. The respiratory symptoms, such as wheeze, sneezing, coughing, and shortness of breath, were highly prevalent, with FVC values indicating compromised lung function in some workers. A proportion of employees were ignorant of the dust and chemical hazards associated with road building. These findings highlight the urgent need for protective measures, including mandatory high- quality PPE, routine health monitoring with spirometry, and environmental controls like cleaner fuels and dust suppression, strict enforcement of air quality regulations, Pa ge 26 https://journals.e-palli.com/home/index.php/ajec Am. J. Environ. Clim. 4(3) 19-27, 2025 and worker education awareness campaigns. Future research should include longitudinal studies to assess long-term effects, biomonitoring for health impacts, indoor-outdoor exposure comparisons, and comparative geographic comparisons in other regions to support national policy development. Immediate action is critical to safeguard workers’ respiratory health and ensure compliance with environmental and occupational safety standards. REFERENCES Abdullahi, M. S. A., Abdikafi, E. A., Abdifitah, M. A., & Ahmed, M. H. (2022). Environmental Impact Assessment in construction activities for Dahab Tower Building Mogadishu. American Journal of Environment and Climate, 1(3), 1–5. https://doi. org/10.54536/AJEC.V1I3.773 Adetoun-Mustapha, B., Blangiardo, M., Briggs, D. J., & Hansell, A. L. (2011). Traffic air pollution and other risk factors for respiratory illness in schoolchildren in the Niger-Delta region of Nigeria. Environmental Health Perspectives, 119(10), 1478–1482. https://doi. org/10.1289/EHP.1003099 Boadu, E. F., Okeke, S. R., Boadi, C., Osei Bonsu, E., & Addo, I. Y. (2023). Work-related respiratory health conditions among construction workers: a systematic narrative review. BMJ Open Respiratory Research, 10(1). https://doi.org/10.1136/BMJRESP-2023-001736 Bwala, J. M., Amadi, A. N., Iwuala, C. C., & Enebeli, U. U. (2025). Occupational health problems: An assessment of the cardiovascular health status of road construction workers in Imo State, Nigeria. European Scientific Journal, 21(21), 64. https://doi. org/10.19044/ESJ.2025.V21N21P55 Cohen, A. J., Anderson, H. R., Ostro, B., Pandey, K. D., Krzyzanowski, M., Künzli, N., Gutschmidt, K., Pope, A., Romieu, I., Samet, J. M., & Smith, K. (2005). The global burden of disease due to outdoor air pollution. Journal of Toxicology and Environmental Health. Part A, 68(13–14), 1301–1307. https://doi. org/10.1080/15287390590936166 Ekpenyong, C. E., Ettebong, E. O., Akpan, E. E., Samson, T. K., & Daniel, N. E. (2012). Urban city transportation mode and respiratory health effect of air pollution: a cross-sectional study among transit and non-transit workers in Nigeria. BMJ Open, 2(5). https://doi.org/10.1136/BMJOPEN-2012-001253 Fang, X., Chang, R., Zuo, J., Zhang, W. E., Zou, Y., & Li, K. (2025). How do environmental and operational factors impact particulate matter dynamics in building construction? - Insights from real-time sensing. Journal of Environmental Management, 380, 125098. https:// doi.org/10.1016/J.JENVMAN.2025.125098 Geldenhuys, G., Wattrus, M., & Forbes, P. B. C. (2022). Gas and particle phase polycyclic aromatic hydrocarbon emission factors from a diesel vehicle engine: Effect of operating modes in a developing country context. Atmospheric Environment: X, 13, 100158. https://doi. org/10.1016/J.AEAOA.2022.100158 Hasan, M. M., Basak, R., Sujan, M. H., Kabir, M. N., Das, D., Aritro, S. S., & Howladar, M. F. (2021). An assessment of the impact of industrialization on physical environment and socio-economic conditions around the Alipur industrial area, Bangladesh. American Journal of Agricultural Science, Engineering, and Technology, 5(2), 309–325. https://doi.org/10.54536/ AJASET.V5I2.102 Isara, A. R., Adam, V. Y., Aigbokhaode, A. Q., & Alenoghena, I. O. (2016). Respiratory symptoms and ventilatory functions among quarry workers in Edo State, Nigeria. Pan African Medical Journal, 23(212). https://doi.org/10.11604/PAMJ.2016.23.212.7640 Kunar, S., & Mandal, G. (2025). Advanced welding technologies. John Wiley & Sons, Inc.; Scrivener Publishing LLC. Landwehr, K. R., Mead-Hunter, R., O’Leary, R. A., Kicic, A., Mullins, B. J., & Larcombe, A. N. (2023). Respiratory health effects of in vivo sub-chronic diesel and biodiesel exhaust exposure. International Journal of Molecular Sciences, 24(6), 5130. https://doi. org/10.3390/IJMS24065130/S1 Lynch, H. N., Goodman, J. E., & Bachman, A. N. (2021). Lung physiology and controlled exposure study design. Journal of Pharmacological and Toxicological Methods, 112, 107106. https://doi.org/10.1016/J. VASCN.2021.107106 Mandal, A., & Dutta, S. (2022). Pulmonary functions and work-related musculoskeletal disorders of road construction workers of West Bengal, India. International Journal of Occupational Safety and Health, 12(3), 185–195. https://doi.org/10.3126/IJOSH. V12I3.40316 Mason, R. J., Broaddus, C., Martin, T., & King, T. (2010). Murray and Nadel’s textbook of respiratory medicine. In Murray and Nadel’s Textbook of Respiratory Medicine 5th ed. (5th ed.). Saunders. Mishra, K., & Krishnan, G. (2016). Carbon monoxide poisoning. Journal of Marine Medical Society, 18(2), 179. https://doi.org/10.4103/0975-3605.204476 Mo, S., Wang, Y., & Xiong, F. (2022). Identification and prioritization of key health hazards to workers in roadway construction. Transportation Safety and Environment, 4(2). https://doi.org/10.1093/TSE/TDAC009 Nikolay, S. (2018). Types and specifics of construction machines used in road pavement dismantling. Architecture and Engineering, 3(2). https://doi. org/10.23968/2500-0055-2018-3-2-54-60 Offiah, A. U., Amadi, A. N., & Azuamah, Y. C. (2022). Measurement of air pollutant levels and the occurrence of environmental lung diseases in Umuahia Metropolis, Southeastern Nigeria. International Journal of Science and Healthcare Research, 7(4), 128–133. https://doi.org/10.52403/IJSHR.20221017 Ogbeibu, A. E. (2014). Biostatistics: A practical approach to research and data handling (A. E. Ogbeibu, Ed.). Mindex Publishing Company Limited. Owolabi, T. O. S., Ajayi, O. O., & Olofu, D. A. (2024). Pa ge 27 https://journals.e-palli.com/home/index.php/ajec Am. J. Environ. Clim. 4(3) 19-27, 2025 Assessment of air pollution levels from a building construction site on Lagos Island. ABUAD Journal of Engineering Research and Development (AJERD), 7(2), 229– 235. https://doi.org/10.53982/AJERD.2024.0702.22-J Rodney, M., Kuku, V., & Joyce, S. (2024). Indoor and outdoor NO2 and SO2 levels in 13 randomly selected preschools from 7 districts in Mpumalanga Province, South Africa. Public Health Challenges, 3(2), e175. https://doi.org/10.1002/PUH2.175 Sarabi, E. R., Poursorkhabi, R. V., & Ravanshadnia, M. (2025). Using the clustering method to find the final environmental parameters coefficients in road construction projects. Scientific Reports 2025 15:1, 15(1), 1–13. https://doi.org/10.1038/s41598-025-88737-3 Singh, R., Singh, K., Sharma, A., & Rout, C. (2023). Assessment of ambient air quality status at different railway bridge construction sites. Annals of Biology, 39(2), 282–287. Thacher, J. D., Emmelin, A., Madaki, A. J. K., & Thacher, T. D. (2013). Biomass fuel use and the risk of asthma in Nigerian children. Respiratory Medicine, 107(12), 1845– 1851. https://doi.org/10.1016/J.RMED.2013.09.009 Toronto Environmental Alliance. (2024). Types of Construction Pollution. Toronto Environmental Alliance. https://www.torontoenvironment.org/types_of_ construction_pollution US Department of Labor Occupational Safety and Health Administration. (2024). Control silica dust. OSHA. https://www.osha.gov/silica-crystalline Wallbanks, S., Griffiths, B., Thomas, M., Price, O. J., & Sylvester, K. P. (2024). Impact of environmental air pollution on respiratory health and function. Physiological Reports, 12(16), e70006. https://doi. org/10.14814/PHY2.70006 Wang, G., Brandenburg, J., & Chen, D. (2025). Introduction to modern infrastructure construction. Taylor & Francis. https://doi.org/10.1201/9781003197768 WHO. (2021). WHO global air quality guidelines. World Health Organization. https://iris.who.int/bitstream/ handle/10665/345329/9789240034228-eng.pdf Yankson, I. K., Karikari, A. K., Okyere, P., Koranteng, A., Afukaar, A. K., Otupiri, E., Donkor, P., Mock, C., & Owusu-Dabo, E. (2023). Occupational injuries among road construction workers in Ghana: Burden, mechanism and severity. Postgraduate Medical Journal of Ghana, 12(2), 101–107. https://doi.org/10.60014/ PMJG.V12I2.338 Yasmeen, R., & Hafeez, F. (2023). Effect of particulate emissions on the respiratory system of workers belonging to different Industries: an overview. Archives of Respiratory Research, 2(1), 1–9.