Environment Pollution and Climate Change
Open Access

Collection of certain pollutants in the air which counter affects the health of a wellbeing human, animal and plant life is known as air pollution. According to the World Health Organization (WHO); 1.4 million deaths from strokes every year, 2.4 million deaths from heart diseases every year, 1.8 million deaths due to lung disease and cancer every year and 7 million premature deaths every year are attributable to air pollution. Air is everywhere and so is its influence polluted air can adversely affect the human health, buildings, monuments, plants, ecosystems and the list is endless. Polluted air has been linked to climate as particulate matter absorbs or reflects sun light and affect cloud formation and rainfall pattern of a place [1].

Pollutants such sulphur dioxide, nitrogen dioxide and carbon monoxide are released into the atmosphere through various combustion processes; burning of fossil fuels such as coal, oil, natural gas and gasoline are the main sources of these pollutants. Particulate matter pollutants is a mixture of solid particles and liquid droplets that are added into the air by dust ash, fly ash, soot, smoke, aerosol and condensing vapors suspended in the atmosphere for longer periods of time [2].

Bengaluru is often manifested through the arduous battles that are fought by the citizens to save the city. The IT capital of the country has an ever growing population, now estimated to be over 1.2 crore [3].The rise in the population is directly related to the rise in the number of vehicles, around 1750 new vehicles are getting registered in the city every day and the vehicle population in Bengaluru has crossed 80.45 lakhs [4]. This has substantially had a tremendous effect on the city’s ambient air quality and health. This paper is an attempt to analyze the critical pollutants such as SO₂,NO₂ and RSPM, together constituting the Air Quality Index, using this information this paper also tries to analyze the general health effects these pollutants cause on both long and short term exposure. Due to the socio-economic and environmental challenges associated with rapid urbanization, it is connected with increasing levels of ambient concentration of air pollution. Main contributor of air pollutants in Bengaluru is the transport sector.

In the year 2018, there has been a report that the number of vehicles in Bangalore has crossed 80 lakhs, by this number we can estimate the amount of unprecedented emission into the air that is going to pollute the air up to a great extent. Increase in number of non transport vehicles (mostly two wheelers) is caused due to the rapid expansion of city without development of proper infrastructure. These vehicles not only cause emission of RSPM, SO₂ and NO₂ but also HC and CO which has led to increase in their concentration in air. Diesel consumption in vehicles emits SO₂ and particulate matter of all size. Particulate matter of size less than 2.5 and 1 μm is expected to have increased due to increase in consumption of diesel. High concentration of RSPM level due to construction activity can be managed if proper care is taken during construction [5].

On a global perspective, the effect particulate matter has proven that women are at a greater risk and also sometimes fatal due to prominent effect of particulate matter. Women showed a relative risk for fatal CHD of 1.42, 1.38, and 1.22 with each increase of 10 micrograms per cubic meter (μg/m³) of airborne PM2.5, PM10 – 2.5, and PM10, respectively, in the air pollution they encountered during the four years preceding death. Postmenopausal women showed higher relative risks of 1.49, 1.61, and 1.30 for each 10 μg/m³ increase in PM2.5, PM10–2.5, and PM10, respectively. Neither O₃, SO₂, nor NO₂ was associated with fatal CHD on its own. O₃ and to a lesser degree SO₂ (but not NO₂) increased the effect of all sizes of PM [6].

Population increase causes a significant positive impact on ambient air pollution [7]. Demand for land, food, transport, energy, natural resources and environmental infrastructures increases with the population rise and ecological balance is disturbed which in turn increases human and socio economic activities leading to increase in ambient air pollution. Backbone of economic development is energy consumption. However environmental pollution and its degradation are caused by unsustainable production and consumption patterns [8]. Reduction in life expectancy and increasing mortality is significantly caused by increased ambient air pollution. However, sustained economic development, along with energy efficiency are potential options for reducing ambient air pollution while improving quality of life and environmental sustainability [9]. By evaluating all the analysis done by various other researchers, RSPM contributes the most to the air pollution throughout the world. In the recent past all the other gaseous components seems to be under control except for the levels of RSPM.

Field sampling

Under National Ambient Air Quality Monitoring Programme (N.A.M.P), Karnataka State Pollution Control Board is monitoring Ambient Air Quality at 7 ( Graphite India Limited, KHB Indl Area, Peenya Industrial area ,Victoria Hospital , Amco batteries, Yeshwanthpur Police Station and International Machine tools accessories at Peenya ) locations using ‘ Respirable Dust Sampler’ (RDS) in Bangalore City by Conventional method. Four air pollutants viz., Sulphur Dioxide (SO₂), Oxides of Nitrogen as NO₂ and Suspended Particulate Matter (SPM) and Respirable Suspended Particulate Matter (RSPM/PM10), have been identified for regular monitoring at all the locations. The monitoring of pollutants is carried out for 24 hours (4-hourly sampling for gaseous pollutants and 8- hourly sampling for particulate matter) with a frequency of twice a week, to have 104 observations in a year.

Data Quality

A majority of the air pollution monitoring stations across the country are operated manually and it is unclear how the 8-h samples are used for regulatory purposes of assessing whether locations are meeting the 24-h NAAQS, since an 8-h sample only captures a snapshot of the actual levels. Further, it is likely that singular pollution episodes are either not accounted for, or have an undue influence on the measurements resulting in under- or over-reporting of PM10 concentrations. Manual monitoring also results in a delay in data collection, transmission, and availability, although the increasing number of CAAQMS are allowing data to be streamed to the CPCB website in near real-time overcoming some of the aforementioned concerns [10].

Calculation of AQI

On the Field Data Log, fill in the top portion of the form including: the date/time of visit, the site identification, sampler identification, site name, filter ID number, sample start and stop dates and times, and field operator initials.

10^3=unit conversion factor for milligrams (mg) to micrograms (μg)

The index of specific pollutant is derived mainly from the physical measurement of pollutants like SPM, RSPM, SO₂ and NOx. There are several methods and equations used for determining the AQI. In the present study AQI for each location in the study area has been estimated with the help of a mathematical equation given below.

AQI=1/3[{SO₂/SSO₂}+{NOX/SNOX}+{RSPM/SRSPM}}] × 100

Where,

SO₂=Individual Values of sulphur dioxide

NOX=Individual values of oxides of nitrogen

RSPM= Individual values of Respirable suspended particulate matter and

SSO₂, SNO₂ and SRSPM=Standards of ambient air quality of sulphur dioxide, oxides of nitrogen, Respirable suspended particulate matter [11].

Calculation of Exceedance Factor

Also, the Central Pollution Control Board (CPCB) developed a formula known as the Exceedance Factor (EF) so that it is easy for everyone to understand the pollution level.

EF=Observed Annual Mean of Criteria Pollutants/Annual Standard For Respective Pollutant

Therefore, Air Quality can be classified into the following:

Critical Pollution (C): EF>1.5

High Pollution (H): EF belongs to [1.0-1.5]

Moderate Pollution (M): EF belongs to [0.5-1.0]

Statistical Analysis

The statistical analysis was performed using Microsoft Excel 2010 to obtain graphs with respect to the trends that are being observed in the obtained data from KSPCB. Along with excel, we also used R Software to analyse the relationship between the pollutants and the Air Quality Index. Pearson correlation analysis (CA) was employed to analyse the inner relationships among elements.

Air pollution measurement in Bengaluru

Under the National Ambient Air Quality Programme (NAMP), the Karnataka State Pollution Control Board (KSPCB) has installed pollution recording apparatus at various locations throughout the city (Table 1). In this paper, the following locations are used for the analysis:

Table 1: Analysis on the Air Quality Trend from 2011-2018

• ITPL (Industrial Belt)

• Yelahanka (Industrial Belt)

• Peenya (Industrial Belt)

• Yeshwanthpur (Residential Belt)

• S.G.Halli (Residential Belt)

• Amco Batteries (Moderate Belt)

• City Railway Station (Moderate Belt)

• Victoria Hospital (Sensitive Belt)

Also, the Central Pollution Control Board (CPCB) developed a formula known as the Exceedance Factor (EF) so that it is easy for everyone to understand the pollution level.

EF= Observed Annual Mean of Criteria Pollutants/Annual Standard For Respective Pollutant Therefore, Air Quality can be classified into the following:

• Critical Pollution (C): EF>1.5

• High Pollution (H): EF belongs to (1.0-1.5)

• Moderate Pollution (M): EF belongs to (0.5-1.0)

• Low Pollution (L): EF < (0.5-1.0)

Analysis of Air Quality Index

As for the health impact of air pollutants, AQI is an important indicator for general public to understand easily how bad or good the air quality is for their health and to assist in data interpretation for decision making processes related to pollution mitigation measures and environmental management. Basically, the AQI is defined as an index or rating scale for reporting daily combined effect of ambient air pollutants recorded in the monitoring sites [12]. As a result an equation, which transforms the parameter, values by means of numerical manipulation into a more simple and precise form can be obtained. The index of specific pollutant is derived mainly from the physical measurement of pollutants like SPM, RSPM, SO₂ and NOx. There are several methods and equations used for determining the AQI. In the present study AQI for each location in the study area has been estimated with the help of a mathematical equation given below (Table 2).

Table 2: Levels of Health Concern

AQI=1/3({SO₂/SSO₂}+{NOX/SNOX}+{RSPM/SRSPM}}) × 100

Where,

• SO=Individual values of sulphur dioxide

• NOX=Individual values of oxides of nitrogen

• RSPM= Individual values of Respirable suspended particulate matter

and

• SSO, SNO and, SRSPM=Standards of ambient air quality of sulphur dioxide, oxides of nitrogen, suspended particulate matter (10).

From Figure 1(a, b), It is evident that in ITPL (Industrial area) the AQI was around 110 in 2011 which has seen an increase until 2014, and after that the graph has been falling with an increase in the year 2017 due to BMRCL initiation of metro work in this area, this led to an increase in particulate matter due to the construction requirement at this site. In Yelahanka we can approximate a steady fall in the AQI over the years. This is mainly due to the changes in industrial regulations that have been adopted by the industries. Also, in Peenya we can observe a moderate AQI inspite of the industries because there is not much combustional processes taking place in this area.

Figure 1: Levels of AQI

In residential areas, Amco Batteries residential area had observed a consistent increase until 2014 after which there has been a steady fall until 2018. The same trend is noticed at S.G Halli, while Yeshwanthpur has not been noticed with any improvement over the trend it seems to fluctuate every year. In sensitive areas, like Victoria Hospital the trend seems to fluctuate but with improvement of air quality.

In moderate areas, like City Railway Station the trend has been fluctuating over the trend with not much improvement this is because of passengers who arrive at the railway station opt for various modes of transportation (i.e cabs, auto rickshaws, etc.), which increases in the combustion in this area.

Analysis of SO₂

The sources of SO₂ applicable to Bangalore are mainly due to the burning of fossil fuels and diesel exhaust, and the salient health effects attributable to it are known to be inflammation of the respiratory tract, dysfunction of lungs and irritation of the eyes. SO₂ also causes health illnesses such as coughing, aggravation of asthma, chronic bronchitis and respiratory tract infections [13].

The permissible limits of SO₂ in the industrial, residential and moderate areas is50μg/m³, while for the sensitive areas it is 20 μg/m³.

From the Figure 2, In the case of industrial areas, the levels at ITPL during 2011-12 has dropped by 25.6% followed by a 69% drop in the year 2014-15, although there was an increase in the levels by 66% at Peenya in the year 2011-12 it was followed by a subsequent drop in 2012-13 by 53%,while Yelahanka has had a drop of 10% in the year 2011-12 followed by a drastic fall in the year 2014-15 by 66%.There has been an overall reduction in the levels of SO₂ at these industrial sites.

Figure 2: Analysis of SO₂

In the case of residential areas, the levels of SO₂ at SG Halli had initially dropped by 40% in the year 2011-12 but subsequently there was equal increase in the following year, however, in the year 2014-15 the levels of SO₂ had dropped by 62%. At Yeshwanthpur we observed an alternating level of SO₂ every subsequent year. At Amco Batteries there was fall by 47% in the year 2011-12 followed by another drop in 2014-15 by 66%.

In the case of sensitive area, Victoria Hospital had observed a slight increase in the 2011-13, however it was followed by a drastic decrease of 64% in the year 2014-2015.

Overall, the downward trend in the level SO₂ has substantially contributed well to the society in reducing the respiratory and child mortality rates in the city. The reason behind the downward trend could possibly be due to change in fuel types and its quality.

Analysis of NO₂

Breathing air with a high concentration of NO₂ can irritate airways in the human respiratory system. Such exposures over short periods can aggravate respiratory diseases, particularly asthma, leading to respiratory symptoms (such as coughing, wheezing or difficulty breathing), hospital admissions and visits to emergency rooms. Longer exposures to elevated concentrations of NO₂ may contribute to the development of asthma and potentially increase susceptibility to respiratory infections. People with asthma, as well as children and the elderly are generally at greater risk for the health effects of NO₂ [14]. The permissible levels of NO₂ in Industrial and residential areas is 40μg/m³ and in sensitive areas is 20 μg/m³.

From the figure 3, In the case of Industrial areas, in the regions of ITPL the level of NO₂ has dropped 8.3% in the year 2011-12 and increased by 11.6% in the year 2013-14 and interestingly the following there was drop by 37%. Surprisingly, such a pattern in the trend has been recorded at all Industrial sites (i.e. ITPL, Yelahanka and Peenya).These locations have overall faced a drop through the years 2011-13 followed by an increase during 2014-15 which was subsequently followed by a drop during the year 2015-16. These kinds of fluctuations have occurred at all industrial sites.

Figure 3: Analysis of NO₂

In the case of residential areas, a similar pattern is observed at the recorded residential sites (i.e. Yeshwanthpur, S.G.Halli, Amco batteries) , a fluctuation the levels of NO₂ with a significant drop in the year 2015-16 followed by an increase in upcoming years, despite fluctuations in the levels of NO₂ at different locations, they seems to be under the permissible limits.

In the case of sensitive areas, such as Victoria Hospital the levels of NO₂ have crossed the permissible limits throughout the trend, this is mainly due to traffic congestion in this area, slow moving traffic causes higher rates of combustion produces considerable amounts of NO₂ into the atmosphere.

In the case of moderate areas, such as City Railway Station the trend in the levels of NO₂ is not predictable as there is no specific pattern being observed, but it does follow a similar trend with respect to the industrial and residential locations. There was significant decrease of 72% from 2011-14 followed by 50% increase in the year 2015.

Analysis of Respirable suspended particulate matter (RSPM)

Karnataka has seen dramatic shift in terms of air quality during the period 2011-2015. The PM10 has significantly increased over the years in certain locations due to use of old vehicles, possible fuel adulteration, re-suspension of dust due to increased traffic, absence of water spraying, emission from traffic jams, obstruction to movement of pollutants, use of DG sets during power cuts, low wind velocity and inversions during winter and nights. Increase in the number of high rise buildings is obstructing wind movement, thereby making pollutants almost stagnant in the city [15].

PM10 is thought to contribute to cardiovascular and cerebrovascular disease by the mechanisms of systemic inflammation, direct and indirect coagulation activation, and direct translocation into systemic circulation. Respiratory diseases are also exacerbated by exposure to PM. PM causes respiratory morbidity and mortality by creating oxidative stress and inflammation that leads to pulmonary anatomic and physiologic remodelling [16]. The standard permissible limits for all areas are 60 μg/m³.

In the case of Industrial Areas, ITPL experienced a high peak of 230 μg/m³ due to the onset of BMRCL construction for the metro line leading to release of many small particles during construction and also the re-routing of roads caused slow moving traffic, hence, increasing the particulate matter in the year 2014. But, following this year we can observe a significant drop in the levels of particulate matter (PM10) in this area, which shows a good sign awareness. Overall, the average RSPM concentration exceeds by 2.4 times the permissible limits. In Yelahanka, there is a significant decrease throughout the trend, even then they exceed the permissible limits by 2.15 times. In Peenya, a bell shaped curve is being observed with its peak during 2014 after which there is a consistent fall in the level of RSPM concentration.

From the figure 4, in the case of residential areas, Yeshwanthpur does not follow any particular trend the levels of particulate matter has been fluctuating throughout, also on an average the level of RSPM seems to be 1.8 times higher than the standard permissible limits, in the same way Amco Batteries also observes a fluctuating trend throughout the analysis, and also on an average the level of RSPM seems to be 2 times higher than the permissible limits. Fortunately, in S.G.Halli the levels of RSPM seem to be under control throughout the analysis.

Figure 4: Analysis of PM10

In the case of sensitive areas, Victoria Hospital had been adversely affected in the year 2012 and 2014 with an unexpected rise in the levels of RSPM by 150% in the year 2012 and 75% in the year 2014 ,fortunately , from 2015 the levels have been dropping drastically and is in the standard control limits.

In the case of moderate areas, City Railway Station has been adversely affected by the levels of RSPM which seems to be having an upward trend throughout the analysis with an average increase of 20% every year.

Recent studies clearly suggest that current standards for PM may not be protecting general public and children, the standards should be revised. The health effects of PM are well documented, but there is no evidence of a safe level of exposure for which no adverse health effects occur. Monitoring of air pollution needs to be improved in many cities, the local authorities should develop dose response models on public health, which can be used to predict health of public. Particulate air pollution can be reduced using advanced technologies, stricter air quality standards, limits for emissions from various sources, reducing energy consumption, changing modes of transport, land use planning, using cleaner modes of transport [17].

Analysis of correlation matrix

By obtaining the correlation matrix between the Air Quality Index (AQI) and the various pollutants (Figure 5), there is a benefit of evidence to observe the correlation picturesquely. On the basis of this matrix we can observe that, in 2011, there is a positive correlation between AQI and PM10 which is greater than both the other combinations( AQI Vs. SO₂ & AQI Vs. NO₂).This trend is being observed throughout the analysis from 2011-18, which concludes that the highest influence on AQI is caused due to PM10. By calculating the Exceedance Factor (EF) for PM10, 70% of the trend has an EF>1.5 which means these areas are critically polluted by particulate matter PM10. OC, EC, Sulphate, ammonium, K, V, Ni, Cu, Zn, Pb, As, Cd and Se are mainly in PM2.5 fraction of particles, while chloride, nitrate, Na, Mg, Al, Fe, Ca, Ti and Mn are mainly in PM2.5-10 fraction. The major components such as sulphate, OC and EC account for about 70-90% of the particulate mass. Enrichment factors (EF) for elements are calculated to indicate that elements of anthropogenic origins (Zn, Pb, As, Se, V, Ni, Cu and Cd) are highly enriched with respect to crustal composition (Al, Fe, Ca, Ti and Mn).

Figure 5: Annual Correlation between various pollutants with the Air Quality Index (AQI)

Analysis of SO₂ vs. NO₂ vs. PM10

By obtaining this graph (Figure 6), we can conclude with evidence that the particulate matter (PM10) in Bangalore has been over the standard limits at an alarming rate. While, SO₂ and NO₂ are within the standard limits causing not much harm to the environment around us. The gaseous component NO₂ has been almost constant after 2015, but it is in control. Furthermore, the gaseous component SO₂ been steadily decreasing since 2015, which is a very good sign for the environment in Bangalore.

Figure 6: Analysis of SO₂ vs. NO₂ vs. PM10

In all the metropolitan cities and popular tourist locations the particulate matter is out of control (Figure 7). In metropolitan cities these levels are out of control due to increasing population because the evolution the IT world in metro cities, which leads to increasing number of vehicles in turn leading traffic congestion. At tourist locations, the increase in particulate could be due to various factors, such as tourist vehicles, and also for example, at Varanasi the rituals include a lot of burning adding dust significantly into the atmosphere which increases the amount of particulate matter. In the year 2018, there has been a report that the number of vehicles in Bangalore has crossed 80 Lakhs; by this number we can estimate the amount of unprecedented emission into the air that is going to pollute the air up to a great extent. As the excerpt from the article says that “Transport is the main contributor of air pollutants in Bengaluru”.

Figure 7: Analysis of AQI of metropolitan cities

While the projected rate of population increase may be reduced, even moderate population growth is likely to lead to substantial increases due to passenger and freight travel demand in the city, due to introduction of Metro, Monorail, BRTS, fuel price etc. The increasing geographic dispersion of metropolitan population is also likely to increase aggregate transportation demand, since the greater number of trips will also be longer and public transport will be less efficient and universal [18]. Bengaluru being the third most populous city in the country is a platform for a lot of technological start-ups and IT hubs. Bengaluru hosts many leading Biotechnology companies, with immense importance and support to its research and development fields. With 40% of India’s IT industry located in Bangalore, the city is among the most favoured destination for IT and other knowledge-based industries. The city’s IT and related services account for about 55% of Karnataka’s state gross domestic product.

By evaluating all the analysis done by various other researchers, RSPM contributes the most to the air pollution in Bangalore. In the recent past all the other gaseous components seems to be under control except for the levels of RSPM (Figure 8).

Throughout, we are able to analyse that the levels of RSPM (Figure 8) are proving to be hazardous to our environment. By WHO, the main contributors to this component is reported to be is dust, waste burning, transport, Diesel Generator sets, Industries, domestic cooking and heating. The standard limit of RSPM is 60μg/m³, and in most of the recorded sites this component in manifolds higher that the standard limit. Hence, through this paper we can draw conclusions that there should be adequate amount of awareness being spread amongst the contributors making them aware of the hazards being posed by this component.

Figure 8: Particulate matter