Research Article - (2011) Volume 1, Issue 1
Dayanand Science College, Latur, Maharashtra, India
The present study aims to measure the concentration of various pollutants present in the ambient air. The primary focus of the study was on Respirable Suspended Particulate Matter (PM10) and Suspended Particulate Matter (SPM) although it also deals with other pollutants like SO2 and Nox. High volume Respirable dust sampler (RDS machine) with Thermo electrically cooled gaseous sampling attachment is used for sample collection. Ambient air monitoring is done at three different sites in Latur city comprising Residential, Commercial and Industrial areas. RDS machine was operated continuously for 48 hours at each site in a weak covering a period of six month. Result of investigation indicates that concentration of RSPM and SPM are exceeding the National Ambient Air Quality Standard at residential and commercial area whereas the concentration of SO2, NOX is bellowing the prescribed limits. Increasing vehicular activities are more responsible for the emission of Particulate matter (PM10). The measure causes includes inadequate improper traffic management system, road condition, absence of effective mass rapid transport system.
Ambient air quality, RSPM, SPM, SO2, NOX, traffic density
Study Area
Latur is a major district in Maharashtra state of India. It is well known for its quality of education, administration, food-grain trade and oil mills. City is situated 636 meters above mean sea level. The entire district of Latur is situated on the Balaghat plateau, 540 to 638 meters from the mean sea level. Annual temperatures range from 13 to 41 °C, the highest maximum temperature ever recorded was 45.8 °C. The lowest recorded temperature was 6.9 °C. Rainfall occurs in the monsoon season from June to September, varies from 9.0 to 693 mm/month. Average annual rainfall is 725 mm.
Both the gaseous and particulate components of atmospheric aerosols and particularly atmospheric pollutants contribute to the deterioration of air quality. Pollution has become a local as well as a regional issue of big cities due to industrial centers and surroundings of transport routes, especially roads and highway [1]. The increasing development of human activities has given rise to a significant increase in atmospheric pollutants which may have an impact on human health [2]. Air pollution is one of the most serious environmental problems in India. In India, urban air pollution is the result of emissions from a multiplicity of sources, mainly stationary, industrial and domestic fossil fuel combustion, motor vehicles emissions and ineffective environmental regulations. Adverse effects of air pollution include an increase in cardiovascular and respiratory deaths among elderly people as well as increased hospital admissions for heart and respiratory diseases. It is well known that health effect associated with air born particles are depends on there toxicity. The extent to which air born particles penetrates into the human respiratory system is mainly determined by the size of the penetrating particles [3]. There are several epidemiologic studies which have demonstrated a direct association between atmospheric inhalation of particulate matter and respiratory diseases, pulmonary diseases and mortality especially in urban areas.
Particulate matter
PM can be classified considering their size. The smallest particles have very short lifetimes in air because their attachment to larger particles. The largest particles are short lived and remain airborne near to their source due to their high rate of sedimentation [4]. PM may be originated by some natural and anthropogenic sources. Natural sources exceed anthropogenic emissions, but the latter are frequently concentrated in urban environments. Natural sources of atmospheric particles are volcanic out gassing, forest fires, sea salt (directly emitted), and gas phase conversion of other atmospheric compounds. Anthropogenic sources are mainly burning of fossil fuels (industrial, transport and domestic burning), diverse industrial processes, mining and agriculture. Industrial and transport emissions are a significant source of particles mainly due to combustion of fossil fuels. They can be responsible of high concentration of particles in the air in great urban settings. However, the distribution of atmospheric particles in urban settings will depend on the characteristics of the urban planning. In canyon streets higher PM emitted by car engines have been found closer to the ground [5]. PM is important for public health impact in urban settings. The effect of PM on health has been often studied in relationship to hospital admissions due to cardiovascular and respiratory diseases, but also with some types of cancer
Oxides of nitrogen
Motor vehicles significantly contribute to ambient nitrogen oxides (NOX) although all motor vehicles emit oxides of nitrogen majority of on road emission occurs from diesel vehicles [6]. The long term exposure to nitrogen dioxide, peoples may found to exhibit increased incidence of chronic cough and decreased lung function parameter.
Sulfur dioxide
Although motor vehicles emit sulfur dioxide and other sulfur containing compounds, traffic sources typically make only small contribution to ambient concentration [6] whereas near most industries are also responsible for sulfur dioxide emission. The sulfur dioxide is known as major respiratory irritant since many years.
Measurement of PM10 and SPM
Sample collection and data analysis was carried out by using a commercially available Respirable dust sampler (RDS- Envirotech APM 411TE model), on a weekly basis from June 2010 to December 2010. The particulate pollutant concentrations were estimated by drawing the measured volume of air into the covered housing of RDS. Usually, the air was drawn at a flow rate of 1.1 to 1.2 m3 per minute. The air inside the sampler passed through a combination of cyclone separator and filter in two stages. At the first stage, the cyclone separator was used to collect the bigger particles (particles in the size range of 10 to 100μm). The rest of the particulates in the size range of 2.5 to 10μm were collected over a previously dried and weighed glass micro fibre filters (Whatman GF/A, 203*254 mm). RDS is operated continuously for 48 hours. However filter paper and cyclone cup was replaced at interval of 8 hours as per central pollution control board norms and conditions .Thus, the collection inside the container attached with the cyclone separator could give the mass of PM10–100, and the collection over the filter paper could represent the mass of PM10 (Respirable particulate matter (RPM)). The loaded and unloaded filters were weighed after conditioning them in desiccators and oven. Finally, the SPM (Suspended particulate matter) concentration was calculated by summing the PM10 and PM10–100 concentrations.
Measurement for SO2 and NOX
Sample collection and data analysis was carried out by using a commercially available Thermo electrically cooled gaseous sampling attachment to RDS machine. Frequency of Sample collection is of 4 hours duration, machine works for two days at each site in weak. TCM and arsenite are used as absorbing reagent for SO2 and NOX respectively. Collected samples are then bring to laboratory and analyzed by West & Geake method for SO2 and Jacob & Hochheiser method for NOX. And from the procedure concentration of SO2 and NOX in μg / m3 is obtained.
Ambient air was monitored covering a period of six month from July to December. Six filter paper and cyclone cup were collected by using RDS at each weak from one site. The statistical results RPM for different sites have been presented in table1. The observed minimum RPM concentration was 93mg/m3 and maximum was 125 mg/m3 at residential area. Minimum RPM concentration was 90mg/m3 and maximum was 131 mg/m3 at commercial area. Minimum RPM concentration was 42mg/m3 and maximum was 99mg/m3 at Industrial area. Average RPM concentration was112 mg/m3, 104 mg/m3, 70 mg/m3 at residential, commercial and Industrial areas respectively. Average SPM concentration was 210 mg/m3, 245 mg/m3, and 147 mg/m3 at residential, commercial and Industrial areas respectively. It was noticed that average concentration of PM10 and SPM at residential as well as commercial areas are above the National ambient air quality standards, India. This may be due to the vehicular activity.
Table 1. Monthly average concentration of RSPM (PM10) in μg/m3 at three sites
Table 2. Monthly average concentration of SPM in μg/m3 at three sites
Table 3. Monthly average concentration of SO2 μg/m3 at three sites
Seasonal variations are also found at all sites. During the month of October the concentration of SPM, PM10, SO2 and NOX at sensitive and commercial area are found to be maximum. The reason may be increased October heat and festival activity like Dashra and Diwali [7]
The particulates are directly emitted into the atmosphere through natural and manmade (anthropogenic) processes including transportation, fuel combustion, industrial processes, land cleaning, wild fires and solid waste disposal [8]. In urban conditions, small aerosol particles are mostly emitted from combustion processes, i.e. car engines and industry. Urban aerosols have a higher proportion of vehicular emissions, which are in very fine size range. The larger particles correspond to the effects of human activities including road dust raised by vehicular motion, building activities and industrial emissions [9]. From the particle formation studies, it could be assumed that the majority of the submicron particles were primary emissions from traffic, or at least particles were formed very close to the sources (car engines) of precursor gases [8]. In addition to this the use of construction & demolition processing facilities is a growing trend. However, a consequence of this process is the generation of Particulate matter [10].
The statistical results sulfur dioxide and oxides of nitrogen for different sites have been presented in table 4 and 5. Average concentration of SO2 and NOX was bellowing the permissible limit of National ambient air quality standards, India at three sites.
Table 4. Monthly average concentration of NOX μg/m3 at three sites
Table 5. Average Concentration (μg/m3) of different pollutants for six Months at three sites
Table 6. National ambient air quality standards for different parameters in (μg/m3) For 24 hours
Figure 1: Showing Monthly average concentration of RSPM (μg/m3)At residential, commercial and industrial area
Figure 2: Showing Monthly average concentration of SPM (μg/m3) at Residential, commercial and industrial area
Figure 3: Showing Monthly average concentration of SO2 (μg/m3) At residential, commercial and industrial area
Figure 4: Showing Monthly average concentration of NOX (μg/m3) At residential, commercial and industrial area
The present study has provided a preliminary assessment of RPM, SPM, SO2 and NOX concentrations and its frequency distributions in Latur city. The Average RPM and SPM concentrations showed a well-defined variation and are higher in residential, commercial areas. The concentration of RPM is corresponds to SPM. And the average concentration of SO2 and NOX was bellowing the permissible limit of National ambient air quality standards, India at three sites. In general transportation, small-scale industries, and elevated rate of combustion of convectional fuels are found to be the source of particulate pollutant in Latur city. The highest concentration of RPM and SPM at residential, commercial area might be attributed pollution from automobiles. Traffic-derived aerosol particles were emitted into the atmosphere due to abrasion processes of automobile components such as the brake or tire wear. Therefore, the emissions and abrasion of the components of automobiles might be the major contributors to the mass of total particles along with emissions from some small-scale industrial sources [11]
