Measurement and Impact Assessment of PM 10 in Ambient Air of BSCIC Bagerhat

The study measured the concentration of coarse particulate matter (PM10) in the ambient air of Bangladesh Small and Cottage Industries Corporation (BSCIC) Bagerhat in order to evaluate its impact on workers’ health. 14 knownvolume air samples were obtained through Envirotech APM 541 PM10 Particulate Sampler. The short-term (6 hours) samples were taken from 9 industrial units in the winter season of October, 2015 to January, 2016. Simple gravimetric analysis showed large variations in concentrations in distinct industrial units. The minimum concentration was found 33.61 μ/m in the outdoor premises of a coconut oil mill and the maximum was found 471.38 μ/m in the house of a rice mill. The pollutant sources were detected as cabinless husking machines and soot from boilers and fryers. A questionnaire survey was conducted to evaluate the mostly occurring symptoms of Chronic Obstructive Pulmonary Diseases (COPD) and bronchoconstriction among workers. The highest prevalence of symptoms of bronchoconstriction (OR = 7.1; 95% CI = 2.3 21.9) was found among workers in rice mills and eye disturbances (OR = 2.7; 95% CI = 0.9 8.6) had the highest prevalence in coconut mills. Monitoring of air quality, providing personal respiratory prevention and improvement in machineries were required in the study area for a healthy environment.

desh along with a variety of agricultural enterprise. The inputs for seasonal postharvest operations are raw agricultural products. All industrial processes are fueled by agricultural by-products and charcoal while they (total 79 estates in Bangladesh) unloose a variety of refuse that is potentially degrading the environment [2].
Agro-based industries are noted as one of the major stationary sources of air pollution in Bangladesh [3]. In BSCIC Bagerhat, agro-processes such as threshing, shelling, drying and husking are done without monitoring or evaluating the effects of great amount of grain dust produced. Rice husk, rice-bran, coconut-coir and charcoal may cause air pollution when processed or burnt in open and if not disposed of properly, it may create allergic reactions in workers [4].
Particulate matter is the major pollutant of concern internationally, as it is in Bangladesh [5]. In the major cities here, the concentration of particulate matter has been steadily increasing in recent years, with an annual average much higher than the prescribed World Health Organization (WHO) guidelines [3]. The health effects are mostly associated with inhalable particles in the range of 10µm Equivalent Aerodynamic Diameter (EAD) and less [6]. Varied concentrations of PM 10 (225 µg/m 3 -1600 µg/m 3 ) generated from bagasse-fired boilers; vehicular emission and road construction; animal confinements and fodders; soil tillage operations; silica and cotton dust influenced respiratory disturbances, i.e., Chronic Obstructive Pulmonary Disease (COPD), chronic bronchitis, pneumonitis and excess risk of laryngeal cancer among workers [7] [8] [9] [10]. 25% increase in patients with COPD in winter season was found, enlisting its symptoms as frequent cough, shortness in breath and tightness in chest certifying dust and smoke as the causes for such ailments [11]. Also, when particulate matter lodged in the lungs, it caused chronic respiratory problems including emphysema, pneumonia, bronchitis, asthma and respiratory tuberculosis etc. [12]. Moreover, organic dust may contain pollen, fungal spores, fungal hyphae, mycotoxins, bacteria and endotoxins [13].

Site Selection
Occupational exposure to particulate matter in agro based industrial operations had scarcely come to focus in Bangladesh despite having an agro-based economy. Maximum PM 10 concentration in a sugar mill in Kushtia was found 380.339 µg/m 3 [7]. Air quality monitoring in this sector is yet to strengthen. The workers are not conscious about the health effects of PM 10 . In such circumstance, the largest agro industrial complex in Khulna division was chosen for the study.

Study Area
BSCIC is situated beside the Khulna-Bagerhat Sadar Road of Bagerhat District in the Division of Khulna in southwest Bangladesh. Small scale (production capacity around 700 kg/day) rice processing mills, coconut oil manufacturing mills, Open Journal of Air Pollution tin processing mills, biscuit mills and pulse processing mills were chosen for air sampling. The study was conducted in November, 2015 to January 2016 with average temperature ranging from 23˚C to 19˚C. The general directions of the wind in winter are north-westerly over the western Bangladesh [3] and the wind speed varies between 2 km/h to 11 km/h [14]. The driest month is December with 8 mm monthly precipitation [14].

Status of Department of Environment (DoE) in BSCIC Bagerhat
Under the Environment Conservation Act (ECA), 1995 and the Environment

Methodology
The study was dealt through both quantitative and qualitative data collected primarily.

Evaluating Health Risk by Questionnaire Survey
Based on previous studies and documented eye and pulmonary disturbances due to exposure to PM10, a questionnaire was structured, adopting British Medical Research Council (BMRC) Questionnaire [16]. The key points had been on symptoms of eye irritation or inflammation, COPD (i.e., shortness of breath, tightness in chest, arrhythmia) and bronchoconstriction (the occurrence of frequent cough i.e., more than six times a day and more than 4 days out of the week; frequent phlegm i.e., bringing up phlegm more than twice a day and more than 4 days a week and getting phlegm in the morning; and frequent sneezing while working). Simple random sampling technique had been applied and the sample size was adjusted [17] to screen 50 workers among 130 permanent employees (employment period minimum 6 days a week for one year). These 50 Open Journal of Air Pollution workers (21 in rice mills, 20 in coconut processing mills and 9 in other mills) were the exposed group to particulate matter emission. Another 50 people were chosen randomly as the unexposed group who were small businessmen, poultry owner, home makers and students living in the BSCIC residence (along the estate margin). They were selected as in the same age group as the exposed group.
MS Excel 2013 and IBM SPSS Statistics v21 software were used for drawing results from the study. Permission was granted to conduct the study from the estate manager of BSCIC, Bagerhat. Every participant was interviewed with his/her prior consent.

Sources of PM10 in the Study Area
Reconnaissance survey revealed that generation of coarse particles initiated from the unloading of raw agricultural products in the mill premises. Then they are i.e., from 8 am to 12 am and from 2 pm to 6 pm due to poor ventilation.

Status of PM10 in Different Industrial Units
The rice and coconut processing mills each had two distinct working zones, indoor mill houses and outdoor drying premises, while the biscuit mill, tin mill, pulse processing mill and BSCIC office had single zone in each. The concentrations found in each zone varied widely and it is shown in Table 1.

Usage of Personal Protective Equipment (PPE)
The walk-through survey revealed that 52% of the total sample population was using only a piece of cloth as a mask or gloves. Interviews found out that 86% of the total of them is unaware of any health impact of the dusty environment they were working in and 12% stated that the PPE they were using were inefficient and insufficient. 5% of them felt it was uncomfortable to use masks and gloves due to the hot and humid weather.
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Health Status of the Workers
Presented in Table 2, 40% and 42% of the sample population working in rice mills had trouble with their eyes while working in the mill houses and in the premise respectively. Moreover, 16% worker regularly felt shortness of breath during normal pace of activity and 23% of rice mill workers experienced allergic reaction from dust in the mill house.
On the other hand, the mostly occurred (in 40% of workers of mill house) disturbance among coconut oil mill workers was found to be eye irritation and inflammation as shown in Table 3. Table 4 shows that 45% of people working in pulse processing, mill, tin processing mill, BSCIC office and biscuit mill had no disturbances in their health. Among the rest, 11% felt shortness of breath, 22% felt tightness in chest and 22% of them had arrhythmia.
In Figure 1, an overall comparison has been done to have a perception of health statuses of all workers.

Status of Bronchoconstriction among the Workers
Extracts of airborne grain dust are capable of muscle contraction and narrowing air of air-passage resulting in asthma-like syndrome [18].    Table 4. Percentages of disturbances in eye and respiratory health of workers in biscuit mill, pulse processing mill, BSCIC office and tin mill.  bance were higher among the exposed workers. Meanwhile, the differences of symptoms in workers of coconut mills from the unexposed group were significant for eye irritation or inflammation (OR = 2.7;

Comparison of Health Status between the Exposed Workers and the Unexposed Group
95% CI = 0.9 -8.6).
Agro-industries have extremely diverse zone and the contents of particulates depend on where, when and how the dust is produced. The outer premises had sufficient ventilating and dispersing opportunities unlike the mill house. PM 10 concentrations were found much denser than the safe limit due to dust emissions   Eye disturbances (OR = 2.7; 95% CI = 0.9 -8.6) had the highest occurrences in coconut mills, though the concentrations of PM 10 were within the standard.
However, it could occur due to the cumulative effect of stack gas emission from coconut fryers fueled by biomass with charcoal soot from burners. Visibility impairment due to brown cloud from PM 10 emission has been documented [19].
The agro laborers had very vague knowledge about consequences of chronic PM 10 exposure. A study [20] among 588 agro-workers revealed that 75% of them were not very concerned about respiratory health risks related to their profession.
Threshold limits or exposure limits for mineral or organic PM concentrations do not exist yet due to the difficulties to characterize the PMs found in the agricultural products. The technology used is not advanced and engineering controls are very weak in agro-industrial facilities, resulting in the excess amount of dust [21].

Conclusion
BSCIC, Bagerhat is the largest diversified agro-industrial complex of the Southeast Bangladesh. The investigation was conducted to evaluate PM 10 concentration and the effect of its chronic exposure in the workers. PM 10 concentrations found in rice mill houses exceeded the threshold limit of the standard. The highest percentages of symptoms of COPD and bronchoconstriction were found in the mill house workers there. The monitoring system of DoE was found ineffective in the area. The BSCIC, Bagerhat authority should supply the workers with dust masks for personal prevention along with providing technical improvements such as water sprinkling system and closed or covered outlets in machinery. Occupational exposure to dust in the agro-industries should be an important area of interest.