This was a cross-sectional descriptive study aimed at collection of data on exposure to respirable among workers in Apparel processing companies in Export Zone Processing (EPZ), Machakos County, Kenya. The study area was in EPZ Machakos County, Kenya as illustrated in Figure 1. According to EPZA (2020), employ 21,752 employees. Seven of these companies are registered by DOSHS. These had approximately 7800 employees [7] . The four selected factories had clustered department including: Cutting Fusing and pressing; Fabric relaxing and spreading; Midpoint; Office; Packaging; Sewing and Embroidery.

PM_2.5 levels were measured using a potable real time PM measurement (Turnkey Osiris Airborne Particulate Monitor). Osiris was positioned vertically in the Lamp Post Box (LPB) and grub screws and two nobs used hold the equipment within the LPB. The LPB which measures approximately (225 × 380 × 210 mm) was then mounted at least 2 meters from the ground on a stable platform across all the six departments. The mounting was undertaken using a banding tool and straps at the midpoint of every department in the factories. In some instances, the LPB was screwed on a wooded platform/post. The departments included: Cutting Fusing and pressing; Fabric relaxing and spreading; Midpoint; Office; Packaging; Sewing and Embroidery. Measurements were done for at least 8 working hours per factory across four months within the 4 selected factories. A total of ninety-six (96) samples were taken for measurement.

Data analysis was done using Statistical Package for the Social Sciences (SPSS) Version. 25. Data cleaning and validation was performed in order to achieve a clean data set which was then exported into a Statistical Package format (SPSS Version 25 for analysis.

The levels of PM_2.5 are presented in Table 2 below. The companies had variable levels of PMs and these varied from department to department.

The mean dust levels of PM_2.5 was 68.30 ± 24 with a range of 55.21 - 81.39] in cutting, fusing and pressing department, 62.45 ± 25.8 and a range of 48.70 - 76.19 in the fabric relaxing and spreading department, whereas the midpoint department had a mean of 69.90 ± 27.6 and a range of 55.22 - 84.59 µg∙m⁻³. The highest concentrations were recorded in the sewing and embroidery department

Source: Author (2021).

with a mean of 87.49 ± 45.2 and a range of 63.41 - 111.57 whereas offices within the EPZ had a mean of 40.89 ± 24.0 and a range of 6.30 - 55.49 which was lower than levels recorded in the packaging department with a mean of 58.44 ± 21.8 and a range of 46.82 - 70.06 µg∙m⁻³. The overall dust mean level of PM_2.5 in EPZ was 65.61 ± 31.5 µg∙m⁻³.

The findings are in line with Sangeetha et al., (2013) [9] study conducted in Tirupur India in a textile company thatrevealed levels of PM_2.5 varied from department to department. According to the findings, those who worked in the Knitting department PM_2.5 levels were recorded high level at 446.38 µg∙m⁻³ while those who worked in the ironing without process section recorded a low of 101.66 µg∙m⁻³. Further, a study done by Mwelange et al. (2020) [10] in textile companies in Dar es Salaam, Tanzania, found that there was a lot of dust in the weaving department, with a mean of (SD = 0.32), but there was less dust in the finishing department, with a mean of (SD = 0.09). This was associated with dust release and the worker's exposure to it, especially where work textile processes are ongoing.

According to Figure 2, APC1 had PM_2.5 concentration ranging from 50.2 µg∙m⁻³ to 71.5 µg∙m⁻³ with fabric relaxing/spreading and cutting fusing/pressing departments showing the minimum and maximum values respectively. All departments in APC2 except sewing/embroidery had concentration ranging from 54.8 µg∙m⁻³ to 69.5 µg∙m⁻³. Surprisingly, sewing/embroidery had the highest concentration of 154.2 µg∙m⁻³. Similarly, in APC3 the concentration ranged from 35.8 µg∙m⁻³ to 72 µg∙m⁻³. Office had the lowest concentration value. APC4 had concentrations ranging from 26.7 µg∙m⁻³ to 81.1 µg∙m⁻³ with the lowest concentration at office department. In APC3 and APC4 the offices were isolated from the production units, thus the lower concentrations compared to the other departments and factories. The study findings are in line with a study done by Khan et al. (2015) [11] in Philippines to investigate the levels of PM_2.5 concentrations by factories and departments. The findings show that all the departments which include office, fabric relaxing and embroidery and sewing had an average of 58.1 µg∙m⁻³. The high concentration was attributed to the fact that the companies’ settings were in one block housing all the departments. However, a study by Tefera et al. (2020) [12] conducted in China shows that in the sampled and visited companies under the categories of apparel processing had lower concentrations compared to the other departments. For instance, the sewing/embroidery had the highest concentration of 82.8 µg∙m⁻³ while cutting fusing/pressing and fabric relaxing/spreading departments had a low of 25.6 µg∙m⁻³ to 21.9 µg∙m⁻³ values respectively.

The mean concentration for PM_2.5 was significantly different between sewing/embroidery and office department (F = 3.808, P-Value = 0.004) as illustrated in Table 3. The mean was higher in sewing/embroidery department than in office department by 46 µg∙m⁻³. However, the mean concentration was not significantly different within the rest of the departments (P > 0.05). The study findings corroborate with a study conducted by Chen et al. [13] in Indonesia. This study shows that the mean concentration for PM_2.5 was significantly different between packaging and front office department (F = 3.517, P-Value = 0.003). The mean was higher in packaging than in front office department by 37 µg∙m⁻³. However, the mean concentration was not significantly different within the rest of the departments (P > 0.05). On divergent views, a study by Pekey et al. (2010) [14] in Sydney that shows that the mean concentration for PM_2.5 was significantly different between front office and sewing and embroidery department (F = 3.274, P-Value = 0.008). The mean was higher in front office than in sewing and embroidery department by 25 µg∙m⁻³. The mean concentration was significantly different within the rest of the departments as standardized by the P-value (P > 0.05).