suspended particulate matter in ambient air of shillong city ... - indjsrt

Ind. J. Sci. Res. and Tech. 2014 2(6):37-41/Lamare & Chaturvedi Online Available at: http://www.indjsrt.com Research Article

ISSN:-2321-9262 (Online)

SUSPENDED PARTICULATE MATTER IN AMBIENT AIR OF SHILLONG CITY, MEGHALAYA, INDIA *

R. E. Lamare and S. S. Chaturvedi Department of Environmental Studies, North-Eastern Hill University, Shillong -793022, Meghalaya, India *Author for Correspondence ABSTRACT: The present study was carried out to evaluate the RSPM, NRSPM and TSPM concentrations in the ambient air of Shillong City, Meghalaya. Sampling was done in April, 2010. The concentration of RSPM, NRSPM and TSPM at Station 1 (Dhankheti Junction) varies from 81.24 µg/m3 to 261.43 µg/m3; 73.17 µg/m3 to 265.54 µg/m3 and 212.49 µg/m3 to 467.94 µg/m3, respectively. The overall RSPM and TSPM concentrations were found to exceed the permissible limit during the study period. Based on the results obtained, the concentrations of particulate matter in the ambient air at Stations 1 was attributed mainly by motor vehicle emission produced from various types of automobiles (both diesel and petrol driven) plying in the area. However, their concentrations at Station 2 (NEHU campus) were found comparatively lower and are within the limit. Key Words: Ambient Air, RSPM, NRSPM, TSPM, Shillong and Meghalaya INTRODUCTION Air monitoring assessment is an imperative investigation undertaken for determining and understanding the degree, nature and status of the ambient air quality of an area. Population growth, industrialisation, exponential rises in number of vehicles and improper implementation of stringent emission standards make the problem of air pollution worse (Ravindra et al., 2001). More than 90% of air quality monitoring stations of Indian cities has reported particulate concentrations exceeding the recommended guidelines (TERI, 2003). These pollutants enter into the atmosphere in the form of gases or particles. Increase in vehicular pollution is one of the most important factors responsible for deterioration of air quality in most Indian cities (Morawska et al., 2002; Gokhale and Patil, 2004; Sharma et al., 2006; IIR 2006).

Figure 1: Map of the Study area Suspended particulate matter (SPM) consists of smoke, dust, fumes and droplets of viscous liquid. SPM are particulate having aerodynamic diameter less than 100 micron which tend to remain suspended in the atmosphere for a long period of time. In most of the cities in India, the level of SPM in ambient air has been reported to frequently exceed the permissible limits (Saseethanan and Meenakshi, 2003). SPM is one of the major air pollutants responsible for degradation of the ambient air quality and may have adverse effects on human health because they can penetrate deep into the respiratory system (Pope et al., 1995; Schwartz et al., 1996). Particulate matter suspended in the atmospheric air having aerodynamic diameter less than 10 micron in size are refers to as respirable suspended particulate matter (RSPM) or PM10. These particulate are small enough to be inhaled deep into respiratory tract and pulmonary system of human beings and pose health related problems to person inhaling it. Non Respirable

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Suspended Particulate matters (NRSPM) are particles above 10 micron or larger than PM 10 in size. The sum of both PM10 and NRSPM represents total suspended particulate matter (TSPM). The present study was carried out with an objective to quantify the level of RSPM, NRSPM and TSPM in the ambient air of the Shillong city, Meghalaya. Study area The study was conducted in Shillong city, Meghalaya. The two sampling stations selected for this study were shown in Figure 1 and described as given below: Dhankheti (Stations: 1): It lies between 25o34’0.78”N and 91o53’26.28”E. The sampling station is situated at 1531 meters elevation above the sea level. Sampler was kept near the Dhankheti junction at the height of 2-3 meters above the ground. This is one of the heaviest traffic routes in the city as it falls under the National Highway-44 where hundreds of vehicles are plying through this area every day ranging from two wheelers, light vehicles and heavy vehicles running throughout the day. According to National Ambient Air Quality Standards (NAAQS), the sampling stations can be categories under Residential, rural and other area categories (CPCB, 2000). However, this area also falls under the sensitive zone considering the presence of the Woodland Hospital and two educational institutes (St. Peters College and the Loreto Convent School) which are just few meters away from the road. NEHU Campus (Stations: 2): It lies at 25o36’43”.54N and 91o54’0.09”E with an elevation of 1413 meters above the sea level. Sampler was kept in front of the Department of Environmental Studies. The area is characterised with pine forest and minimal vehicle plying through the road. The only main activity that may contribute to particulate matters in the air was the construction activities taking place near the stations. MATERIALS AND METHODS In this study, ambient air quality parameters like total suspended particulate matter (TSPM), non respirable suspended particulate matter (NRSPM) and respirable suspended particulate matter (RSPM) were monitored by using Respirable Dust Samplers (Model: Envirotech APM-460BL) equipped with a cyclone in it. Sampling was done in April, 2010. The high efficiency cyclone retain particulate matters >10 micron whereas allowed the 10micron was carefully removed and then transported to the laboratory to obtained its final weight.

Figure 2: A- RDS at Station 1; B and C - Glass filter paper after 24 hours of sampling at Station 1and Station 2, respectively

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The difference between initial and final weight of the filter paper and dust collector cup to the total volume of the air drawn during sampling period determines the amount of respirable suspended particulate matter and non respirable suspended particulate matter, respectively. Total suspended particulate matter comprises the sum of respirable suspended particulate matter (particle size 10 µ). Calculations involved are given below: (A). Calculation of Air Volume Sampled (m3) (Q1 + Q 2 ) ∗ T 𝑉= 2 Where, Q1= Initial air flow rate.m3/min Q2=Final air flow rate.m3/min T= Sampling time in minutes. (B). Calculation of concentration of RSPM and NRSPM. [Final Weight (Wf ) − Initial Weight (Wi )] ∗ 106 = Volume of Air (m3 ) Where, Wf= Final weight of filter paper/ dust collector cup, g Wi= Initial weight of filter paper/ dust collector cup, g V= Air volume sampled, m3 106= Conversion of g to µg (1g=106µg) (C). Calculation of TSPM = RSPM + NRSPM (μm/m3 ) RESULTS AND DISCUSSION The 24 hours particulate matters concentrations from two different sampling stations collected and computed during the study period were discussed as given below: Respirable Suspended Particulate matter (RSPM) or PM 10 The concentration of RSPM at Station 1 varies from 81.24 µg/m3 to 261.43 µg/m3. Based on National Ambient Air Quality Standards (NAAQS), the sampling stations can be categories under Residential, rural and other area categories. The permissible limit for RSPM in such categories for 24 hours is 100 µg/m 3. The results revealed that 73.33% out of the total sampling period RSPM exceeded the permissible limit at Station 1. However, RSPM concentration at Station 2 ranged from 13.34 µg/m3 to 95.02 µg/m3 and all are within the limit (Fig. 3). The values in the former station were found comparatively higher than that of the latter sampling stations. This clearly indicates that an elevated RSPM concentration at Dhankheti was attributed mainly by the increasing number of vehicles plying in the area leading to significant increase in the emission load to the ambient air.

Figure 4: RSPM concentration at sampling stations Non-Respirable Suspended Particulate matter (NRSPM) At Station 1, the 24 hour concentration of NRSPM was found in the ranged 73.17 µg/m3 to 265.54 µg/m3. However, its concentrations were reported between 6.16 µg/m3 to 162.02 µg/m3 at Station 2 (Fig. 4). The re-suspension of coarse and fine soil dust from unpaved portion of the road and its dispersal by the action of wind leads to the rise of NRSPM concentration in the air (Almeida et al., 2007; Rathar et al., 2014).

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Figure 5: NRSPM concentration at sampling stations

Figure 6: TSPM concentration at sampling stations Total Suspended Particulate Matter (TSPM) The permissible limit for TSPM for 24 hours sampling at industrial, residential-rural and other area and other sensitive area was 500 µg/m3, 200µg/m3 and 100µg/m3, respectively. The TSPM concentration at Station 1 and Station 2 monitored during the study period was observed between 212.49 µg/m3 to 467.94 µg/m3 and 67.51 µg/m3 to 226.24 µg/m3, respectively. Based on the prescribed standard limit, TSPM concentrations at Station 1 were reported to exceed the given limit for 24 hour sampling period (Fig. 5). TSPM concentration at Station 2 at some period crossed the limit due to elevated concentration of NRSPM in the ambient air. CONCLUSION Based on the investigations carried out on 24 hours sampling basis, the overall elevated values of RSPM and TSPM concentrations recorded in its ambient air at Station 1 area was attributed mainly by motor vehicle emission produced from various types of automobiles (both diesel and petrol driven) plying in the area. Besides, the vehicular emission is the only major contributing air pollution sources in the area. Various studies have also indicate that vehicular emission is the main reasons for the rise of various pollutants in the atmosphere particularly the suspended particulate matter accompanied with heavy traffic/ high traffic densities, vehicular traffic, poor traffic management and narrow road (Seinfeld, 1989; Horaginamani and Ravichandran, 2010; Hosamane and Desai.2013; Charan and Sahel, 2014). In contrary, the ambient air at Station 2 was reported within the prescribe limit. ACKNOWLEDGEMNET The authors would like to express their sincere gratitude to Mr. Phight Majaw, Mr. Rimoon Lamare, Mr. Phabien Sunn and Mr. Thangjam Somendro for their support and contributions. We also thank the Head, Department of

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Environmental Studies, North-Eastern Hill University for providing all necessary infrastructure and laboratory facilities to carry out the study. REFERENCES Almeida SM, Farinha MM, Ventura MG, Pio CA, Freitas MC, Reis MA & Trancoso MA (2007). Measuring air particulate matter in large urban areas for health effect assessment. Water Air Soil Pollution, 179 43-55. Charan PD & Sahel H (2014). Study of Respirable Dust in Ambient Air of Bikaner City and Its Impact on Human Health. Applied Journal of Hygiene, 3(1) 11-14. Gokhale SB & Patil RS (2004). Size distribution of aerosols (PM10) and Lead near traffic intersections in Mumbai, India. Environment Monitoring Assessments, 95 311-324. Central Pollution Control Broad (CPCB, 2000). Air Quality status and trends in India. National ambient air Quality Monitoring series: NAAQMS/14/1999-2000 163. Horaginamani SM & Ravichandran M (2010). Status of ambient air quality in Tiruchirappalli city. Journal of Ecotoxicology and Environmental Monitoring, 20(1) 51-54. Hosamane SN & Desai GP (2013). Urban air pollution trend in India - present scenario. International Journal of Innovative Research in Science, Engineering and Technology, 2(8) 3738-3747. India Infrastructure Report (IIR) (2006): 3i Network Urban Infrastructure. Oxford University Press, New Delhi, India. Morawska I, Jyaratna ER, Mengersen K, Jamriska M & Thomas S (2002). Differences in air borne particle and gaseous concentration in urban air between weekdays and weekends. Atmospheric Environment, 36 4375-4383. Rather PA, Wanganeo A, Mushtaq B, Wani MA & Bhat BA (2014). Air quality monitoring and effects of air pollution on animal health in Bhopal, India. International Journal of Modern Biology and Medicine, 5(3) 100-110. Pope CA, Thyb MJ & Namboodiri MM (1995). Particulate air pollution as a predictor of mortality in prospective study of US adults. American Journal of Respiratory and Critical Care Medicine, 151 669-674. Ravindra K, Mittal AK & Van Grieken R (2001). Health risk assessment of urban suspended particulate matter with special reference to polycyclic aromatic hydrocarbons: A review. Reviews on Environment Health, 16 169-189. Saseetharan MK & Meenakshi P (2003). Analysis of seasonal variations of suspended particulate matter and oxides of nitrogen with reference to wind direction in Coimbatore city. IE(I)J. EN,vol.84, pp.1-5 Schwartz J, Dockery DW & Neas LM (1996). Is daily mortality associated specifically with fine particles?. Journal of Air and Ware Management Association, 46 927-936. Seinfeld HJ (1989). Air Pollution: Physical and Chemical Fundamentals. McGraw-Hill, New York. Sharma K, Singh R, Barman SC, Mishra D, Kumar R, Negi MPS, Mandal SK, Kisku GC, Khan AH, Kidwai MM & Bhargava SK (2006). Comparison of trace metals concentration in PM10 of different location of Lucknow city. Bulletin in Environment and Contamination Toxicology, 77 419-426. Tata Energy Research Institute (TERI, 2003). Green India 2047, Renewed, New Delhi.

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