Development of Internet of Things (IoT) Based Monitoring of Hazardous Exhaust Compounds in Air - A Review

. Presence of pollutants in Air is the most prominent problem globally confronted now a day. The extreme use of fueled vehicles and rapid urbanization has deteriorated the air quality. This deteriorated air contains hazardous compounds like Mono-oxides & Di-oxides of carbon, Sulphur, Nitrogen, Atmospheric Particulate Matter. Exposure to such hazardous compounds in the air for a long time can cause damage to the human health. Traditional air monitoring systems consists of monitoring stations. As far as traditional air quality monitoring methods are concerned, they are highly expensive and requires a regular maintenance. Due to these limitations, these stations are deployed in small numbers and also it provides indicative values of the sensed data. This monitored data has low resolution and precision. This paper proposes framework for the development of smart and portable system using Internet of Things (IoT) for monitoring of hazardous exhaust compounds in the air using real time. This framework consists of different types of sensors and a controller that are used for monitoring and assessment of the air quality. Also it is used to check the presence of hazardous compounds emitted by different industries and share this data through IOT. The outcome of the proposed research work can be utilized by industries as well as by other agencies to carry out an audit of hazardous exhaust components present in air, so as to take necessary precautions and to save human.


Introduction
During past few decades, world has witnessed tremendous Industrial growth and rapid urbanization. Due to this industrial growth, employment has increased manifold. On the other hand it has also contributed to the release of hazardous compounds in the air. Due to great pace of Urbanization & industrial growth, environment has witnessed deterioration of the quality of air. The boundless use of crude oil private and commercial vehicles as well as machines in the industries, discharge a large amount of perilous gases and gaseous particles matter in the air. Pure Air is important ingredient of life for every individual. Theses hazardous exhaust compounds released in Air affects the health and overall development of human being [1].
Air in the atmosphere contains heavy metals and hazardous exhaust compounds along, polluting water and agricultural land. Therefore, Release of hazardous exhaust components and particulate matter from exhausted air from vehicles and industries is not a issue of entirely industrial regions but a global problem which influences everyone in the society along with effect on environment [2] . As per the report of World Health Organization (WHO), Out of total population of the world, around 92% used to live in the areas that has presence of such hazardous exhaust compounds. In addition, the report also states that the presence of Hazardous exhaust compounds, particulate matter & hydrocarbons in the exhausted air is the big environmental risk to health of every individual. Moreover, the statistic shows 3 million deaths annually are causing due presence of hazardous exhaust compounds in the air [3] .
Moreover, the number of vehicles commuting on the roads and excessive use of conventional energy sources is one of the major factors for releasing the hazardous exhaust compounds air. There are different types of hazardous exhaust compounds exhausted in air by varied sources, These includes Mono-oxides & Di-oxides of carbon, Sulphur, Nitrogen, gaseous Particles i. e. Perticulate Matter (PM for short) which is having diameters less than or equal to 10 μm is PM10 and the other having diameter less than or equal to 2.5 μm is PM2.5 [4]. It is the Particulate Matter PM2.5 that affects the human with respiratory dieses and may damage the lung or heart. . Constant human exposure to such Hazardous exhaust compounds may invite several health problems based on the exposure duration to it, type of hazardous compounds, and the level of such compounds. The WHO has recommended standard of air quality that demonstrates the effects on health from various hazardous compounds present in the discharged air from industries and societies [4]. Different health effects of theses hazardous exhaust compounds are difficulty in breathing, suffocation, nausea or Irritation of skin etc. The mainly occurring health issues are weakened lung functioning, asthma, respiratory diseases and premature death [5] . Therefore, Innovative system for monitoring the Hazardous exhaust compounds in the exhausted is the need of the hour, so that harm to the human health and ill effects on the environment can be reduced. Moreover, these monitoring systems will help the industries to keep the track of these hazardous exhaust compounds for audit and also and government / other agencies to prepare the policies to healthy environmental conditions for all.

Related Work
Though, sufficient work has been carried out as far as Monitoring of hazardous exhaust compounds in air is concerned using different techniques. But still there is a scope of research to address various untouched hazardous compounds. The intense need for system, that shall monitor the presence of hazardous exhaust compounds in air motivated for the development of the system that is capable of monitoring and assessing the future trends of various hazardous exhaust compounds in air.
Being an essential part, this section outlines the contribution of various research work based on different technologies.
In its work S. Muthukumar et'al [6] proposed a pollution monitoring system, which only monitors the vehicular pollution using different types of sensors. The proposed system is based on IoT and is used to gather the real time values of air pollutants like SO2, CO, CO2, NO and also calculates the percentage of these pollutants. The pollutants that are addressed by the proposed systems are ammonia, oxygen and carbon monoxide etc.
The model for assessing the complexity of air pollution was proposed by Chen Xiaojun et'al [7] in their work air pollution monitoring and forecasting system. It uses several sensors and neural network for monitoring and prediction of the pollutants like temperature, humidity, wind direction, wind speed.
Jen-Hao Liu et'al [8] presented a framework for monitoring air quality. The system is based on wireless sensor networks (WSNs) and global system for mobile communications (GSM). The proposed system only monitors the carbon concentration in air. The LabVIEW program developed is used to manage the system that consists of nodes for sensors, a gateway, and a control center. The data acquired and maintained at the control center. An intelligent IoT model based on Petri Nets (PN) was proposed by Ahmad F. Subahi [9] for monitoring of temperature and guessing the reference temperature that can be used for temperature regulation block. It also put an emphasis on the energy consumption and efficiency of the model. An IoT based monitoring system was proposed by Zhibin Liu1 [10] using Zigbee for monitoring of indoor air quality which monitors PM2.5, CO2, temperature & humidity. The data collected through IoT devices are shared using GPRS / 4G Network. The model monitors the temperature and makes the guessing of the reference temperature that can be used for temperature regulation block. It also put an emphasis on the energy consumption and efficiency of the model.
A Low-cost, open IoT system for carbon Dioxide monitoring in indoor classrooms was proposed by Rafael Fayos-Jordan [11] , which consists of an IoT based system that has open hardware and open-software and architecture in order to measure the CO2 concentration, temperature and relative humidity.
An IoT based models were proposed for monitoring of various hazardous pollutants in air, sound, Water and Soil by different authors [12][13] [14][15] [16] . These models use different types of controllers and sensors for data acquisition and monitoring. These models are capable of monitoring different compounds of pollutants present in air, sound, Water and Soil like various hazardous compounds in air, PH value in industrial effluents etc. A real time system to monitor and analyze air quality is designed that record the data remotely to the server, and update the data via the internet was proposed by Kennedy Okokpujie [ 17] The proposed system was developed using an Arduino microcontroller and it monitors the presence of gaseous, dust pollutants present in air & its level [18] [19] . [20] introduces the IoT crowd-sensing platform using bicycle networks as IoT to provide various services to citizety. The platform is based on research work to guess the most interesting bike-friendly services. This system incorporâtes the services like realtime remote geo-location identification of the bike, tracing of theft and air pollution observation. This information is routed and shared using IoT platform. Air quality monitoring system for Real-time and based IoT with mobile sensing in metropolitan areas was published by Srinivas Devarakonda et al [21] . This system comprises of two models one is installed on public vehicle and other is installed on personal vehicle. Data of Air quality obtained with such acquisition models can be used for a variety of purposes. Patients having respiratory or cardiovascular health issues will find these results valuable in determining less congested routes [20] [21] .

Fulvio Corno et'al
A structured overview of guidelines of existing air quality and standards in force by diefferent juridictions are presented by He Zhang [22] . It also outlined a review and analysis of low-cost, state-of-the-art air quality sensor (LCAQS) systems with relevant specifications such as Range of detection, tolerance measurement, resolution and response time [22] [23] . A structured analysis of the latest systems for the monitoring of indoor air quality using Internet of Things is provided by Jaguriti Saini et al [24] . This document also highlights design considerations for surveillance systems, which highlights different types of sensor, a siutable controller based architecture and connectivity and implementation issues. Also, it addresses the different types of sensors i. e. Thermal sensor, gas sensors for detection of multiple or single gas, along with dust sensor [24] [25] .
Sarath K. Guttikunda et'al [26] [27] presented a survey on discharge of Atmospheric emissions and pollutants by thermal power plants that are governed by coal-fire in India and Air pollution knowledge assessments (APnA) for 20 Indian cities. Their study also provides important information about consumption of coal in thermal power plants and pollutants that are being generated along with surveys of 20 major cities in india against air pollution due to varied sources. The major concern of a pollution monitoring system based on real-time includes various types of sensors, use of Internet of Things (IoT) and communication protocols, capturing the data and its transmission across communication channels, security of data and it's consistency. [28] .

Proposed Methodology
In the proposed work, it is intended to develop a hardware model that will monitor presence of hazardous compounds that industries exhibit in societal area. Here the concept is to use the potential of Internet of Things (IoT) for monitoring the monitor presence of hazardous compounds. This framework proposes an air quality observing framework that enables us to monitor and check the presence of hazardous compounds emitted by different industries through IOT and give alert of precaution to all concerned.
Steps involved in the Air & Noise Pollution Monitoring: -1) Sensor will sense the different hazardous components present in the air.
2) The Sensor output is given to the signal conditioning for converting it in to appropriate level.
3) The output of signal conditioners is given to the IoT controller. 4) IoT controller will process & compare the input samples with that of the standard Parameters available in the database 5) IoT controller will record levels of hazardous exhaust compounds present in an air which can be utilized to develop correlations 6) The system will be validated and if required, it will be modified accordingly. 7) The proposed system will be used to provide benefit to different industries and society with the rapidly increasing use of internet IoT (Internet of Things).

Fig 1. IoT Based System for Monitoring Hazardous Exhaust compound in air
IoT is nothing but the interconnected devices network, which are supported with different kinds of sensors, software architecture, connectivity and necessary electronics circuits to gather and exchange information to make the system more interactive and responsive. Internet of Things (IoT) is basically a architecture in which information exchange and integration allowed between the end user systems and physical world using the existing network [12] [13] .

IoT Controller
IoT Controller is basically a combination of controller and internet connected physical devices. Controller is used to process the sample values read from the sensors. These processed sample values are then fed to the end user devices using internet for creating the data base. Also these sample values can be stored on the cloud.

AI Algorithm
Artificial Algorithm will be incorporated to analyze the sample values and use the appropriate algorithm to predict the future trend of the presence of hazardous exhaust compounds in air.

Conclusion
Detection of different types of hazardous compounds present in the air that is exhausted from various industries is a very essential. This will help in order to reduce harm / damage caused due these hazardous compounds to the human being. The Ambient Air Quality Monitoring Systems (AAQMS) are installed in urban areas by the Pollution Control Agencies in India. These systems require high Installation and Maintenance cost. Therefore, these systems are difficult to install at every industry.
This article portrays an outline for the development of Smart & Low cost, IoT based system for monitoring of hazardous exhaust compounds from various industries. The system in consideration will Collect the air samples of the exhausted air and analyze these samples. Depending on the analysis, it will display the presence of different hazardous compounds in the Air along with their concentration. The proposed system will also incorporate the Artificial Intelligence (AI) based algorithm to estimate the future trends of these hazardous compounds. This will help the concerned industry to take the necessary measures to control the emission of such hazardous exhaust in Air. Moreover, the system will be capable of creating the data base of such past monitoring. This database will be maintained on central server using cloud and can be shared using Internet of Things (IoT) with external agencies for further analysis or for the pollution audit of the concerned industry.