Environmental Air Pollution Monitoring System

Abstract

Over the few Decades there is a rapid growth in the transportation facilities. These facilities are meant to serve the humans and make their life easier. Apart from the advantages these facilities also create serious problems to the environment. The first and the foremost is the severe environmental pollution which has caused deterioration of atmosphere, climate change, stratospheric ozone depletion, loss of biodiversity, changes in hydrological systems. Using Arduino technology the concentration of pollutants in the environment at a particular location is measured and the information is sent to the authorities frequently.

Whenever the concentration of the pollutants increases the prescribed limit, a warning message is sent through GSM. By using this information air pollution can be controlled by regulating the traffic or by bypassing the traffic at that particular location.

Arduino is a single-board microcontroller meant to make the application more accessible which are interactive objects and its surroundings. It calculates the raw data from the sensors and displays it on the LCD panel. The hardware features with an open-source hardware board designed around an 8-bit Atmel AVR microcontroller or a 32-bit Atmel ARM. Current models consists a USB interface, 6 analog input pins and 14 digital I/O pins that allows the user to attach various extension boards.

1. Introduction

Air pollution is a critical environmental issue that cannot be ignored. The increasing trend of the global urbanization results in air-pollutants concentrated in urban areas and megacities. Transportation, road traffic, home heating, industrial emissions, and other local anthropic actions are the major emission sources of toxic gases (NOx, O3, CO, SO2, NH3, H2S), volatile organic compounds (benzene, toluene, xylene), polycyclic aromatic hydrocarbons (PAH), greenhouse gases (CO2, CH4, N2O), particulate matter (PM1.0, PM2.5, PM10), aerosol and dust, heavy metals, pollens in the environment.

Inhaling pollutants for long time causes irreversible damages in human health [1]. The World Health Organization (WHO) reports the air pollution as a significant risk factor for human health. This causes serious problems such as skin and eyes infections, irritations, heart diseases, bronchitis, asthma, lung cancer. Also, air pollution is one of the major causes for many premature deaths. Finally, air pollution not only has bad effects on public health but also on the environment such as acid rains, photochemical smog, ozone layer deterioration and global warming.

Control of air pollution and air quality monitoring are strictly necessary to implement abatement strategies and stimulate environmental awareness in the citizens’ community. Several techniques and technologies can be used to monitor air pollution data [1]. Currently, traditional environmental monitoring methods, such as air quality monitoring stations, are typically precise but expensive and bulky. These high-cost and high accuracy air quality monitoring stations based on chemical analysers are used to address the environmental regulations and standards. Generally, they are less densely employed and provide sensing data at low spatial resolution in the cities. Thus, air quality monitoring systems based on low-cost and accurate sensors to be integrated in wireless sensor networks distributed at high spatial resolution in the smart cities can be a valid and effective tool for real-time ubiquitous monitoring, support decisions, inform general public.

1.1. AIR POLLUTION STANDARDS

Air pollution is a major environmental health threat to humans especially children. For children under five, it can cause chronic obstructive pulmonary disease and lung cancer in adults. Acute lower respiratory tract infections, especially pneumonia, are the biggest killers of young children and cause more than 2 million annual deaths. More than 384 hazardous gases have been identified in the environment. However, of these gases six pollutants: CO, NO2, ground level O3, SO2, particulate matter and lead are the most dangerous and are known as “the common air pollutants” or “criteria air pollutants.” Limits of Gas Pollutants are shown in Table 1.1. The sources and diseases caused by these common air pollutants are as follows [2].

II. LITERATURE SURVEY

Over the years, there have been several regulations made by the Government to control the emission from vehicles, most of them being unsuccessful at the same. The standards and the timeline for implementation are set by the Central Pollution Control Board under the Ministry of Environment & Forests. Bharat stage emission standards are emission standards instituted by the Government of India to regulate the output of air Pollutants from internal combustion engine equipment, including motor vehicles. The first emission norms were introduced in India in 1991 for petrol and 1992 for diesel vehicles. These were followed by making the Catalytic converter mandatory for petrol vehicles and the introduction of unleaded petrol in the market.

On April 29, 1999 the Supreme Court of India ruled that all vehicles in India have to meet Euro I or India 2000 norms by June 1, 1999 and Euro II will be mandatory in the NCR by April 2000. Car makers were not prepared for this transition and in a subsequent judgment the implementation date for Euro II was not enforced. The standards, based on European regulations were first introduced in 2000.

Table1.1: Average Concentration and Maximum Limit of Air Pollutants

Average content in

Pollutant

Chemical symbol the atmosphere

Maximum Limit

(Annual Mean)

Carbon monoxide

CO

10 ppm

35 ppm

Sulphur dioxide

SO2

20 µg/m3

100 µg/m3

Ozone

O3

100 µg/m3

20 mg/m3

Nitrogen dioxide

NO2

40 µg/m3

100 µg/m3

Particulate matter

PM2.5

10 µg/m3

25 µg/m3

Progressively stringent norms have been rolled out since then. All new vehicles manufactured after the implementation of the norms have to be compliant with the regulations. Since October 2010, Bharat stage III norms have been enforced across the country. In 13 major cities, Bharat stage IV emission norms are in place since April 2010.Visakhapatnam as it was called and known as the seaside hill resort with beautiful green-covered hills all around, alas, has been made to acquire the dubious distinction of being the ‘most polluted industrial cluster’ conferred by the Central Pollution Control Board with the highest Comprehensive Environment Pollution Index of 70.82 surpassing even the Patancheru - Bolaram chemical industries belt which at one time the High Court ordered to be closed [4].There are many ways to measure air pollution, with both simple, chemical and physical methods and with more sophisticated electronic techniques. There are four main methods of measuring air pollution.

PASSIVE SAMPLING METHOD:

In this method, we collect the samples and send the samples to the laboratory every day. In the laboratory, the samples are tested using some instruments. The disadvantage of using this method is the results obtained are not accurate and the process involved is not automatic that is it consumes time and also requires technicians in the process of producing the results [5].

B. AUTOMATIC SAMPLING METHOD:Automatic methods produce high-resolution measurements of hourly pollutant concentrations or better, at a single point. The samples are analysed using a variety of methods including spectroscopy and gas. The sample once analysed is downloaded in real-time, providing very accurate information. The disadvantage of using this method is it is not cost effective [6].

C. ACTIVE SAMPLING METHOD:Active sampling methods use physical or chemical methods to collect polluted air, and analysis is carried out later in the laboratory. Typically, a known volume of air is pumped through a collector (such as a filter, or a chemical solution) for a known period of time. The collector is later removed for analysis. Samples can be collected daily, providing measurements for short time periods, but at a lower cost than automatic monitoring methods. The disadvantage of using this method is it is time consuming [7].

III. PROPOSED METHOD BLOCK DIAGRAM

The block diagram for the environmental air pollution monitoring system is shown in Fig. 1.1. It consists of Arduino Uno board, Power supply, Sensors for different gas pollutants, GSM module, LCD display and Buzzer.The sensors can be powered using a regulated power supply of 5V. Sensor MQ-135 detects NOx and CH4, MQ-7 detects CO. Arduino Uno Board acts as a processor and controller. It calculates the raw data from the sensor and displays it on the LCD panel.

Fig. 1.1: Block Diagram for Environmental Air Pollution Monitoring System

IV ALGORITHM AND FLOWCHART

In order to perform entire process, one need to adopt a step by step process and is presented in the form of an algorithm.

Step 1: START.

Step 2: Declaration of sensor data using characteristic curves from respective datasheets.

Step 3: By using this sensor data, calibration of sensors is performed.

Step 4: Calculate RS and RO values.

Step 5: If Gas id=0, then calculate the concentration of Gas id=0 and display on LCD else next Gas id is considered.

Step 6: If Gas id=1, then calculate the concentration of Gas id=1 and display on LCD else next Gas id is considered.

Step 7: If Gas id=2, then calculate the concentration of Gas id=2 and display on LCD else Step 5 is repeated.

Step 8: If concentration of any gas exceeds the prescribed limit, the buzzer is activated and a warning message is sent through GSM else the process repeats.

Step 9: REPEAT.

IV: RESULTS

The concentration of the three major gas pollutants namely, Carbon Monoxide (CO), Methane (CH4) and Nitrogen Dioxide (NO2) are measured at some polluted areas of Vijayawada and whenever the concentration of a particular gas pollutant exceeds its prescribed limit a warning message is sent through the GSM. Fig. 1.3 shows the concentrations of three pollutant gases observed at Municipal Corporation Guest House, Vijayawada on 12th February. The concentrations of NO2 and CH4 are zero ppm since under normal environmental conditions these two gases are present at very low levels (usually in ppb and even lesser). Concentration of CO=0.49 ppm at that instant

Fig. 1.3: Observation on 12th February at Municipal Guest house Vijayawada.

Fig. 1.4 shows the concentrations of three pollutant gases observed at Municipal Corporation Guest House, Vijayawada on 5th April. The concentrations of NO2 and CH4 are zero ppm and concentration of CO=0.74 ppm at that instant.

Fig. 1.4: Observation on 5th April at Municipal Guest House, Vijayawada.

Fig. 1.5 shows the concentrations of three pollutant gases observed at Benz circle, Vijayawada on 5th April. The concentrations of NO2 and CH4 are zero ppm and concentration of CO=0.94 ppm at that instant. Fig. 1.6 and Fig. 1.5 shows the concentrations of three pollutant gases observed near Bike exhaust system. At one instant of time the concentration of NO2= 0.69ppm and the concentration of CO exceeded the prescribed limit as shown in Fig. 1.6. Hence a warning message “CO Limit Exceeded” is sent through the GSM at that instant as shown in Fig. 1.6.

Fig. 1.5: Observation on 5th April at Benz Circle, Vijayawada.

Fig. 1.6: Observation near Bike Exhaust System.

At some other instant of time the concentration of CH4 exceeded the prescribed limit as shown in Fig. 1.7. Hence a warning message “CH4 Limit Exceeded” is sent through the GSM at that instant as shown in Fig. 1.8.

Fig. 1.7: Observation near Bike Exhaust System.

At some other instant of time the concentration of CH4 exceeded the prescribed limit as shown in Fig. 1.8. Hence a warning message “CH4 Limit Exceeded” is sent through the GSM at that instant as shown in Fig. 1.8. Fig. 1.9 shows the screenshot when the message is sent through the GSM module stating that CO and CH4 limits are exceeded at that particular instant when tested near bike exhaust system.

VALIDATION OF SENSOR DATA

Environmental Air Pollution Monitoring System was operated near municipal corporation guest house region in Vijayawada, India to collect the readings of the concentration of Carbon Monoxide in air. The real-time readings obtained from Environmental Air Pollution Monitoring System are tabulated in Table 4.1. The readings obtained are then validated by using the data of ‘Pollution Control Board’, Vijayawada [31]. We compare and validate the real time readings of Environmental Air Pollution Monitoring System of municipal corporation guest house region in Vijayawada with that of ‘Pollution Control Board’ and also with the permissible limits of Carbon Monoxide. The permissible limit for CO concentration for Vijayawada region as per PCB [31] is 10 ppm and the concentration obtained from Environmental Air Pollution Monitoring System is 0.735 ppm, which is well within the permissible limit and is hence valid.

Table 1.2: Real-time Carbon Monoxide Concentration Data Measured

Time interval

Concentration of CO (ppm)

1

0.65

2

0.69

3

0.71

4

0.73

5

0.73

6

0.74

7

0.74

8

0.73

9

0.73

10

0.74

Average

0.72

1. MQ-7 Sensor

2. MQ- 135 Sensor

3. LCD Display

4. Cabinet for mechanical strength

5. GSM module

6. ARDUINO UNO

CONCLUSION

A Sensor based Air Pollution Monitoring System was designed using the wireless sensor network which is cost effective. The system is used to measure concentration of pollutant gases such as CO2, NO2 and other pollutant gases from environment. The pollution data from various sensors arrays is transmitted to a central server that makes this data available to government authority. The data shows the pollutant levels and their conformance to local air quality standards. The system also uses the WHO limits to evaluate the level of health concern for a specific area. It also associates meaningful and very intuitive colours to the different categories, thus the state of air pollution can be communicated to the user very easily.

REFERENCES

T.Subramani,. “Study of Air Pollution Due to Vehicle Emission in Tourism Centre” International Journal of Engineering Research and Applications, Vol.2, Issue.3, pp 1753-1763, 2012..

US Environmental Protection Agency, Office of Air Quality Planning and Standards. Review  of the National Ambient Air Quality Standards for Particulate

Matter: Policy Assessment of Scientific and Technical Information. OAQPS Staff Paper—First Draft. Research Triangle Park,   NC: US Environmental Protection Agency; 2003.

Approved Methods for the Sampling and Analysis of Air Pollutants in New South Wales by the department of environment and conservation NSW.Government Gazette on 24 December 1998, p. 10320

M.U.H. Al Rasyid LU. Nadhori A. Sudarsono Y.T. Alnovinda ""Pollution monitoring system using gas sensor based on wireless sensor network"" International Journal of Engineering and Technology Innovation (IJETI) Taiwan Feb. 2016. 

John D. Ray, David B. Joseph,” A Cost-Effective Method of Obtaining Air Quality Data in Protected Areas.

Dr. Sharad Gokhale ,”Air Pollution Sampling and analysis”. Department of Civil Engineering Indian Institute of Technology Guwahati Guwahati –Assam, India

Active versus Passive Air Sampling by Eddie Salter, SKC Ltd.” https://www.envirotech-online.com/article/health-and-safety/10/skc/active-versus-passive-air-sampling-eddie-salter/923”

Multi-Gas Long Path Air Quality Monitoring System by SANOA” environnement.it /public/articoli/ 53/Files/Sanoa_Scheda_tecnica_uk.pdf

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