The Effect of PM10 and PM2.5 Pollution on Feed Mill Workers (IAEC Ref. 250) Ali Aybek, Selçuk Arslan and Şanver Genç

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1 The Effect of PM10 and PM2.5 Pollution on Feed Mill Workers (IAEC Ref. 250) Ali Aybek, Selçuk Arslan and Şanver Genç ABSTRACT The particulate matter (PM) exposure might result in health hazards including allergies, inflammations in the skin and eyes, intoxications and lung cancer in severe cases depending on the source, the exposure time, size of particulate matters, and the concentration level. The objective of this study was to determine the particulate matter (PM10 and PM2.5) concentrations that the workers are exposed to in feed mills. Gravimetric method was used to determine the PM concentrations by using a personal sampler in different working areas of three feed mills. PM10 concentrations were higher than PM2.5 in feed mills. The greatest PM10 concentration was found in the mill (7867 µg/m 3 ), followed by bulk storage (4855 µg/m 3 ), dosing (2438 µg/m 3 ), and bagging units (2328 µg/m 3 ). PM2.5 concentrations had the same pattern with the highest in the mill (3033 µg/m 3 ), and the smallest in weighing section (782 µg/m 3 ). Both PM10 and PM2.5 concentrations were lower than threshold limits established by OSHA. A survey on the workers revealed that the workers did not have serious complaints about health problems, including coughing, phlegm, tightness in the chest, and breathlessness. Smoking habit of the workers seems to have a effect on their complaints about coughing and phlegm. Keywords: PM10, PM2.5, particulate matter, flour mills, personal exposure 1. INTRODUCTION Human, machine, and environment are the three components of productions systems. The performance of production systems depend not only on the machinery but the human factor and the working environment that surrounds both (Sabancı, 1999). The benefits of working in safe and healthy operating conditions are not limited to workers safety and health, the increased productivity is another resultant of good working conditions. Therefore, the working environment needs to be designed and controlled in accordance with the standards and other requirements in terms of vibration, temperature, relative humidity, gases, and particulate matter (PM) so that anthropometric and psychological requirements of human are fulfilled. Agriculture based industry has a key role in producing animal feed, and has a critical importance in national economies in terms of feed safety. Particulate matter (PM) generation from a variety of different operations in the feed mills is also of importance as the PM inhalation of the workers is a concern in this agri-based industry. Such working environments pose health hazards to workers (Sprince et al., 2000). Particulate matters (PM) are the solid and liquid droplets with different shapes and concentrations in the air with dimensions from 10-3 to 10 3 µm (Batel, 1981). Particles smaller than 10 µm (PM10) are associated with upper respiratory system and particles with aerodynamic diameter less than 2.5 µm (PM2.5) are related to lower respiratory system. Therefore, PM inhalation might cause a variety of nuisances and diseases including allergies, inflammation in the eyes, skin, and lungs, intoxication, lung cancer, and even death in severe cases. The severity of the health hazard depends on the PM source, concentration level, particle size, and exposure duration (Matthews and Knight, 1971; Witney, 1988; Erkan, 1989; 1

2 Omland, 2002; Seifert et al., 2003). The view that organic PM has effects on inhalation functions of industrial workers is gaining popularity (Ahmed et al., 2009). More than half of the animal feed is produced in feed mills in agricultural production in Turkey. Organic PM is generated during the conveying, processing, and bagging feed materials such as corn, soybeans, and wheat. Since no sufficient data is available on PM pollution in feed mills in Turkey, the general purpose of this study was to determine the level of PM concentrations in feed mills, and help increase the awareness on the potential nuisances the workers might experience due to PM exposure. The specific objectives of this study were to: determine PM10 and PM2.5 concentrations in different working areas of commercial feed mills, and compare the measured PM concentrations to standards, measure ambient temperature, relative humidity, and wind speed, and determine whether the ambient climatic conditions are within comfort zone, determine health complaints of workers through a survey and try to relate PM exposure levels with nuisances experienced by the workers. 2. MATERIAL AND METHODS 2.1. Materials A personal PM sampler (Sioutas) was used to collect the PM samples. A controlled laboratory was used to condition the filters for 48 hours at a temperature of 20 C and relative humidity of 50%. A microbalance (Mettler-Toledo UMX2) with a precision of ±0.1 µg was used to weigh filters for gravimetric determination of PM concentration. A thermo-higro-anemometer (Delta OHM DO 9847) was used to determine the ambient conditions during data collection (Figure 1). Personal PM sampler Termo-higro-anemometer Microbalance Figure 1. Measurement devices used to determine PM concentrations and climatic parameters Data were collected in three feed mills in the Kahramanmaras Province in the eastern Mediterranean region of Turkey. The mills had similar specifications and some technical features are given in Table 1. 2

3 Table 1. Some technical features in feed mills Section Feature Explanation Mill Type Hammer mill Capacity (ton/h) 12 Power (kw/unit) 90 Number of units 1 Speed (rpm) 1500 Mixer Type Horizontal mixer Power (kw) 20 Bagging Number of unit Methods PM10 and PM2.5 exposure levels were measured in four working areas of three feed mills, namely bulk storage, dosing, mill, and bagging units. The PM samples were collected with filters in the personal sampler attached to the collar of the operators or workers. To measure ambient temperature, relative humidity, and air speed during PM sampling, a thermo-higro-anemometer was used in a place that can be representative for the working area. PM10 and PM2.5 concentrations were determined using the reference method to determine PM concentrations. The filters were conditioned at laboratory for about 48 hours before they were weighted using the microbalance. After sampling, the filters were reconditioned in the laboratory for another 48 hours and reweighted to calculate the amount of PM on filters. The pump was operated at an air flow rate of 9 L/min and was calibrated before each data collection using the air flow calibrator. The concentration level (µg/m³) for each operation was then calculated. Occupational Safety and Health Organization (OSHA) determines the limit values for exposure duration of 8 hours, which suits to agri-industrial operations. Therefore, OSHA limits were used to determine if PM exposure level exceeds the limits in feed mills. OSHA gives nuisance levels for PM exposure for upper and lower respiratory systems (Table 2). The calculated PM concentration level for each operation was compared to OSHA standards for granular materials to assess the health hazard of the feed mill workers. Table 2. Exposure limits for PM10 and PM2.5 (OSHA) Feature Limit values (µg/m³) Particle size Lower respiratory system nuisance limit 5000 PM2.5 Total nuisance limit PM10 Granular materials dust (wheat, oat, barley) PM PM2.5 The disturbance an operator experiences could be influenced by ambient conditions as well. Measurement of climatic factors may be helpful to make better assessment on the effect of measured factors. Suggs (1991) defined the comfort zone for the temperature in the range of C and relative humidity in the range of 30-70%. The working conditions of operators were compared to these criteria to assess if these factors might have contributed to the health complaints, if any. 3

4 3. RESULTS AND DISCUSSION Average PM10 and PM2.5 concentration levels in four different working areas of three feed mills are given in Figure 2. As easily noted PM10 concentrations were higher than PM2.5 concentrations in all four working areas in feed mills. Second apparent result that can be seen in Figure 2 is that PM10 and PM2.5 were somewhat proportional in each working area. Consequently, the highest and the smallest concentrations were in the same working areas. The greatest PM10 (7867±267 µg/m³) and PM2.5 (3033±208 µg/m³) concentrations were measured in the mill section whereas the smallest concentrations were found in dosing system, respectively with 2328±828 µg/m³ for PM10 and 668±214 µg/m³ for PM2.5. These results suggest that neither PM10 nor PM2.5 concentration was higher than the threshold limit set for PM10 ( µg/m³) and PM2.5 (5.000 µg/m³) by OSHA. Thus, it may be concluded that there is no apparent health hazard to workers in different sections of feed mills PM PM concentration, µg/m PM10 PM10 PM2.5 PM PM2.5 PM2.5 PM2.5 0 Bulk storage Dosing Mill Bagging Working areas in feed mills Figure 2. Measured PM10 and PM2.5 concentrations in different working areas of feed mills In a similar study, Arslan and Aybek (1995) measured 100 to 460 µg/m³ PM exposures in different units of feed mills using a portable real time measurement device. The results found were significantly smaller compared to the findings of this study. The discrepancies between the two studies might have resulted from the simultaneous measurements in the previous study versus reference method used in this study. Multiple mean comparisons might reveal that means are different in different areas in feed mills. Such information, however, might not have practical implications since all measured PM concentrations were below the threshold limits. Thus, the PM10 and PM2.5 means in different working areas in feed mills were not compared statistically in this study. A survey was done on nineteen workers in the three mills in this study. Workers age was between 24 and 48 with a working experience from one year to twelve years. Table 3 shows 4

5 the percentage of the workers in different work areas of the mills. The smallest percentage (10%) is in the mill area because the mill can operate safely without supervision and the operators would like avoid the noisy environment. As a result, the mill operator is not necessarily in the mill area throughout the day. The observation can be done for the workers in the bulk storage sections. A few hours are devoted to convey raw materials to storages when needed or convey different raw materials from storages to the processing units. Thus, workers continuously need to be present in dosing and bagging stations in the feed mills since these operations also are not fully automated. Table 3. Distribution of nineteen workers in working areas in feed mills Working area Percentage of workers (%) Bulk storage 21 Dosing 37 Mill 10 Bagging 32 The type of nuisance the workers might experience due to PM inhalation or respiration includes coughing, phlegm, tightness in the chest, and breathlessness (Table 4). The majority of the workers did not complain about experiencing serious health nuisances. About 38% of the workers reported that they have coughing problem, which was the most common nuisance along with phlegm with 37%. Since workers did not experience tightness in the chest or breathlessness, it may be concluded that there is no obvious effect of PM2.5 respiration on lower respiratory systems of workers. Table 4. Type of health complaints of workers in feed mills (%) Type of nuisance Yes No Coughing Phlegm Tightness in the chest Breathlessness Smoking Smoking could have additional effect on these health hazards. About 38% of the workers were smokers, which is close to the complaint percentages of coughing and phlegm. Thus, coughing and phlegm rates might have been affected by smoking habit, since PM concentration levels were lower than the threshold limits. Detailed health investigations including medical tests and information on health history of the workers could reveal valuable data to differentiate the effect of smoking habits from the effect of particulate matter inhalation and respiration. According to Air Quality Index (AQI), PM10 concentrations are in the danger limit between 301 and 500 µg/m 3. European Directives 1999/30/EC and 96/62/EC impose that in phase 2 (after January 1 st 2010), annual average PM10 concentration should not exceed 20 µg/m³ whereas exposure level may be over 50 µg/m³ only seven days in a year. Thus, standards are strict for general public and for industrial areas. There is no standard that sets a threshold specifying a limit particularly for different working areas of feed mills. However, OSHA determined thresholds limits for an 8-hour shift for PM exposure of granular materials (Table 2), which was used in this study as the limiting values for feed mills. Razote et al. (2008) states that there is an increasing concern for human health, and therefore federal regulations have been established for PM10 (U.S. EPA, 1987) and PM2.5 (US EPA, 1997). The 24-h 5

6 PM10 and PM2.5 standards are 150 µg/m 3 and 35 µg/m 3, respectively. Consequently, EPA standards are used for PM10 and PM2.5 monitoring in agricultural operations as well. Apparently, the standards of AQI, European Directives, and EPA are much strict compared to OSHA standards. Based on this short discussion on different international and national standards, it may be helpful to note that although the feed mill workers were not exposed to PM levels greater than the PM exposure limits established by OSHA, it would be better if the workers used personal protections, especially in the bulk storage area to avoid health nuisances in the long run since health problems are also affected by exposure time. Temperature, relative humidity, and wind speed measurements during PM sampling are given in Table 5. Wind speed in the working environment in feed mills is negligible and hence is not expected to have an effect on human health or on the generation of particulates. Ambient temperature and the relative humidity were within the comfort zone (18-24 C and 30-70%) and were not expected to have negative health effect on workers. Indeed, the measured ambient climatic conditions may vary depending on the season and might have effects on human health. For instance, during winter operations, risks of suffering from flues along with the effect of PM inhalation might contribute to the total nuisance felt by a worker. The data presented in this study, however, does not suggest any treats to workers health in feed mills. Table 5. Descriptive statistics for measured ambient climatic factors in feed mills Working area Factors Average Std. dev. Min. Max. Temperature ( C) 19,11 0,23 18,78 20,72 Bulk storage Relative humidity (%) 52,55 3,20 43,3 58,5 Wind speed (m/s) 0,02 0,04 0,00 0,26 Temperature ( C) 18,23 0,27 17,84 19,57 Dosing Relative humidity (%) 58,00 1,79 53,60 62,2 Wind speed (m/s) 0,03 0,07 0,00 0,61 Temperature ( C) 19,15 1,55 16,62 22,02 Mill Relative humidity (%) 43,93 4,47 37,30 52,70 Wind speed (m/s) 0,03 0,06 0,00 0,41 Temperature ( C) 18,23 0,27 17,84 19,57 Bagging Relative humidity (%) 58,00 1,79 53,6 62,20 Wind speed (m/s) 0,03 0,07 0,00 0,61 4. CONCLUSIONS PM10 and PM2.5 concentrations were determined gravimetrically in the bulk storage, dosing, mill, and bagging sections of three feed mills. Additionally, a survey was conducted on workers to determine the health nuisances that the workers experience so that PM exposures and health complaints of the workers can be related. The followings could be concluded as a result of the findings of this study: PM10 concentrations were always higher than PM2.5 concentrations in feed mills. The highest inhalable (7867 µg/m 3 for PM10) and respirable concentrations (3033 µg/m 3 for PM2.5) occurred in the mill unit. These concentrations were lower than the threshold level ( µg/m 3 for PM10 and for PM2.5) established by OSHA, which do not suggest serious health hazards to an average worker in feed mills. Ambient climatic conditions vary significantly depending on the season. Average temperature (18-19 C) and average relative humidity (43-52%) were within the comfort zone 6

7 (20-24 C and 30-70%) at the time of the measurements. Long term measurements are needed to make accurate assessments on the effects of particulate matter on workers health. Workers in feed mills did not report serious health complaints due to PM inhalation including coughing, phlegm, tightness in the chest, and breathlessness. The low percentages in the complaints (max. 38% for coughing) agree with the PM10 and PM2.5 concentration levels that were less than the threshold limits. Coughing and phlegm complaints seem to emerge more from smoking habits. Detailed investigations on workers health may help differentiate the effect of smoking effects from the effects of particulate matters. 5. ACKNOWLEDGEMENTS The authors would like to express their appreciation to The Scientific and Technological Research Council of Turkey TUBİTAK) for the support of this study. 6. REFERENCES 1. Ahmed, A.H., Bilal, I.E., Merghani, T.H., Effects of exposure to flour dust on respiratory symptoms and lung function of bakery workers: A Case Control Study. Sudanese Journal of Public Health 4(1): Arslan, S., Aybek, A., Dust concentration measurements in agri-industrial facilities. Journal of Agricultural Machinery Science, 1(1), 29-35, İzmir, Turkey. 3. Batel, W., Dust load and dust composition in workplaces in agriculture and load limits and dust protection measures derived thereform. Translated by N. M. Reilly. National Instute of Agricultural Engineering, Wrest Park. Silsoe, Bedford, MK45 4HS. 4. Erkan, N Physiological stresses in workplace and ergonomics. Proceedings of the 2 nd National Ergonomics Congress, Turkish National Productivity Center Publications, 379, 28-38, Ankara. 5. Matthews, J., Knight, A. A Ergonomics in agricultural equipment design. National Institute of Agricultural Engineering, Silsoe. 6. Omland, O Exposure and respiratory health in farming in temperate zones a review of the literature. Ann Agric Environ Med. 9 (2): Razote, E.B., Maghirang, R.G., Guo, L., Tallada, J.G., Auvermann, B.W., Harner III, J.P., Harner III, W.L. TEOM Measurements of PM10 and PM2.5 concentrations at cattle feedlots in Kansas. An ASABE Section Meeting Presentation Paper Number: MC Sabancı, A Ergonomics (in Turkish). Baki Publication, Adana. 9. Seifert, S.A., S.V. Essen, K. Jacobitz, R. Crouch, and C.P. Lintner Organic dust toxic syndrome: a review. Journal of Toxicology: Clinical Toxicology. 41(2):

8 10. Sprince, N. L., Lewis, M. Q., Whitten, P. S., Reynolds, S. J., Zwerling, C., Respiratory symptoms: associations with pesticides, silos and animal confinement in the Iowa farm family health and hazard surveillance project. American Journal of Industrial Medicine. Vol. 38: Wiley-Liss, Inc. 11. Suggs, C.W Thermal environment of agricultural workers: environmental stress, module 10. ASAE, St. Joseph, Michigan. 12. Witney, B Choosing and using farm machines. Copublished in The United States with John Wiley & Sons Inc., Newyork. 8

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