This article will present a simple technical solution for a low-power and real-time air quality monitoring system. The whole package of software and hardware technical solutions applied for recording, transmitting and analyzing data is briefly described. This original monitoring system integrates a single chip microcon-troller, several dedicated air pollution surveillance sensors (for PM10, PM2.5, SO2, NO2, CO, O3, VOC, CO2), a LoRaWAN communication module and an online platform. This system was tested and applied under real field conditions. Depending on the measured values, it provides alerts, or, it can lead to the re-placement of specific components in the exhaust equipment. This article will pre-sent some experimental results, validated also by official measurements of government operated air quality stations

Andea, Petru

Dzitac, Simona

Frigura-Iliasa, Flaviu Mihai

Meianu, Dragoș

Musuroi, Sorin

Simo, Attila

English

Agora University Editing House: Journals

INTERNATIONAL JOURNAL OF COMPUTERS COMMUNICATIONS & CONTROLOnline ISSN 1841-9844, ISSN-L 1841-9836, Volume: 15, Issue: 4, Month: August, Year: 2020Article Number: 3891, https://doi.org/10.15837/ijccc.2020.4.3891CCC Publications Technical Solution for a Real-Time Air Quality Monitoring SystemA. Simo, S. Dzitac, F. M. Frigura-Iliasa, S. Musuroi, P. Andea, D. MeianuAttila Simo*1. Politehnica University Timisoara300006 Timisoara, Piata Victoriei, 2, Romania2. Romanian Academy of Scientists300220 Bucuresti, Ilfov, 3, Romania*Corresponding author: attila.simo@upt.roSimona Dzitac, Dragos, MeianuUniversity of Oradea410087 Oradea, Universitatii, 1, Romaniasimona@dzitac.ro, dmeianu@uoradea.roFlaviu Mihai Frigura-Iliasa,Sorin Musuroi, Petru Andea1. Politehnica University Timisoara300006 Timsoara, Piata Victoriei, 2, Romania2. Romanian Academy of Scientists300220 Bucuresti, Ilfov, 3, Romaniaflaviu.frigura@upt.ro,sorin.musuroi@upt.ro, petru.andea@upt.roAbstractThis article will present a simple technical solution for a low-power and real-time air qualitymonitoring system. The whole package of software and hardware technical solutions applied forrecording, transmitting and analyzing data is briefly described. This original monitoring systemintegrates a single chip microcon-troller, several dedicated air pollution surveillance sensors (forPM10, PM2.5, SO2, NO2, CO, O3, VOC, CO2), a LoRaWAN communication module and anonline platform. This system was tested and applied under real field conditions. Depending on themeasured values, it provides alerts, or, it can lead to the re-placement of specific components in theexhaust equipment. This article will pre-sent some experimental results, validated also by officialmeasurements of government operated air quality stations.Keywords: wireless sensors network, air quality monitoring, LoRaWAN.https://doi.org/10.15837/ijccc.2020.4.3891 21 IntroductionNowadays, air quality monitoring in the urban environment, generally, and near the industrialplants, particularly, is becoming an increasingly important issue. Many, today existing air qualitymonitoring systems are using Wireless Sensor Networks (WSN), Vehicular Sensor Networks (VSN)or other Internet of Things (IoT) based technologies. The shortcomings of these systems, if thetechnology is not well chosen, (e.g. a system based on ZigBee, NB-IoT, LTE-M) is that they requirea large number of sensors and gateways to establish a multi-hop network for ferrying the data to thebackend system. Such approach generally increases the network cost and the energy consumption.If application scenario needs small packages of data, the measuring points has no electricity supplyand needs coverage over large geographical area, for such situa-tions, the Low Power Wide Area(LPWA) networks provide the solution.LPWA networks permits a long communication range, low power consumption, low cost and directM2M access. There are a number of competing standards in the LPWA network space, such: Sigfox,Dash7, Telensa, NB-IoT, Nwave, LoRa, etc.This paper presents a part of a more complex work from the LPWA networks field, ongoingin the Power Systems Department from Politehnica University of Timisoara, in collaboration withETA2U Company. A software-hardware complex of technical solutions for collecting, transmittingand analyzing data is presented within this paper. The proposed pilot system integrates a single chipmicrocontroller, several calibrated air pollution low-cost monitoring sensors (PM10, PM2.5, SO2, NO2,CO, O3, VOC, CO2), LoRaWAN communication module and an online application. The proposedsolution is tested and validated under real field conditions.Depending on the measured values, the application can generate alerts and can propose the replace-ment of certain components in the filtration systems, in case of industrial plants. The authors havealso dealt with the air pollution-monitoring problem in the past. In [10] they offer a practical model ofan automated environment parameters monitoring system for industrial plants, a multifunctional soft-hardware complex of technical solutions for collecting, transmitting, processing and analyzing data.The proposed system in [10] can embed different type of sensors for chemical emissions monitoringin industrial plants. The whole system is based on the LoRaWAN communication protocol and aself-flying drone system. The current project was born to have real-time data about air parameters,over large geographical area, which helps us manage activities in the territories impelled by devices(e.g. traffic management, construction areas, industrial plants).In literature, there are many theoretical studies and proposed solutions regarding air pollutionmonitoring [2], [3, 4, 7, 9] . Many uses cases refer to small geographical areas where WIFI technologyis also suitable. Few projects target large geographical areas and require devices to have low energyconsumption [6, 11]. Existing air quality monitoring systems are using a specific range of sensors tomeasure various air pollutants but tend to only have one PM sensor and do not use LPWA networks[1, 8, 12].The deployment of a thick, reliable wide area network of air quality monitoring system would im-prove the ability to identify sources of pollution, understand person-al exposure, complement existingmonitoring networks and raise air quality awareness among the population.2 Monitoring system descriptionDeploying wireless sensors network over large geographical area requires supporting infrastructure.The pilot project where the monitoring devices were to be installed referred to an industrial area ofabout 25 km2. The longterm strategy intents that this air quality monitoring device to become partof a smart city infrastructure providing concrete data about the air parameters for local residents.The main purpose was to create a low-cost device, which, if needed, to be accessible, even for theresidents, but, at the same time, to provide correct and indisputable results. A Raspberry Pi HardwareAttached on Top (HAT) provides the computation. In the first stage, the team tried the measurementvariant presented in [10], with Waspmote Pro 1.5 and Waspmote 3.0, to which the sensors were added.Later, this support was replaced with an own data acquisition board, on which the sensors andhttps://doi.org/10.15837/ijccc.2020.4.3891 3the communication module were integrated.In this pilot project, we used the LoRaWAN communication protocol, due to its flexibility, ease ofuse, and other advantages offered versus other LPWA technologies, and to the local coverage.This project strong point was the fact that the ETA2U Company has a LoRa net-work at thelevel of the Timisoara municipality, named LoRaTIM. It is a complex network, consisting of CiscoIXM-LPWA-800-16-K9 and Kerlink gateways, with a very good coverage that can be seen on figure1.Figure 1: LoRaTIM network coverage2.1 Hardware systemWithin this pilot project, the team have planned the construction of six devices, for monitoringair quality issues in an industrial area of Timisoara, Romania. With these six devices, the area ofinterest is covered. This area being geographically large for data collection, is is necessary to use theLoRaWAN communication protocol.In the first phase, the solution was tested with the device previously conceived by our team [10],presented in figure 2.Some of the results obtained with this version 1 (with calibrated sensors) were very good (partiallypresented in figure 2), but a major disadvantage was that not all the sensors could be connected onthe same sensor board (PM10, PM2.5, SO2, NO2, CO, O3, VOC, CO2). The results for NO2 for June2018 are presented in figure 3. Similar results were obtained for the other polluting agents, too.In order to cover the entire range of pollutants that have been proposed, should have had todouble the number of sensor boards (figure 2, on the right side), which increased the device cost, thevolume and not least the energy consumption. In addition to the sensors that were placed directlyon the sensor board, the particulate mat-ter (PM) sensor had to be connected to this. This furthercomplicates the situation.In this pilot project, the team used the HPMA115S0-XXX Honeywell particulate matter sensor.This is a laser-based sensor which detects and counts particles using light scattering [5].The detection concentration range is 0 µg/m3 to 1,000 µg/m3, it is fully calibrated, with <6 sresponse time and max 80 mA current supply. Based on IEC61000 stable operation, plus/minus 15%accuracy (PM2.5, PM10) it can be considered a sensor that meets the needs. Because of these, theteam decided to design an own sensor board (one board per device), on which can be connected all thesensors (SO2, NO2, CO, O3, VOC, CO2), HPMA115S0-XXX, the LoRaWAN HAT and Raspberry PiHAT (as shown in figure 4). Thus, on this board can be connected all the seven sensors plus the restof the device elements.All components, are enclosed in an plastic enclosure with IP66 IP rating (as in figure 9), having360 mm x 270 mm x 165 mm (H x W x D) dimensions. Two grids (6 x 4) of 10 mm holes were drilledhttps://doi.org/10.15837/ijccc.2020.4.3891 4Figure 2: Hardware componentsFigure 3: Values recorded for NO2 for one monthon both sides of the enclosure to ensure a constant air flow, for SO2, NO2, CO, O3, VOC and CO2sensors. The HPMA115S0-XXX PM sensor was taken out of the box.Figure 4: Own data acquisition board, developed by ETA2U Innovation2.2 Software systemIn parallel with the development of the monitoring devices, an online platform has been designedfor data analytics and different alerts setting.On this platform, the user can select from the list or on the map the industrial platform of interest,after which he can select the device from which he wants the information about air quality parameters.Figure 5 shows the design of the platform. Because the administrators of the industrial platform didhttps://doi.org/10.15837/ijccc.2020.4.3891 5Table 1: List of hardware used to build one monitoring deviceItem Quantity Unit Price (Euro)Raspberry Pi HAT 1 40Gas sensors 7 10Honeywell PM Sensor 1 35LoRaWAN HAT + antenna 1 45Plastic enclosure 1 37not agree, the location of the devices could not be displayed on the map.The online platform was developed using HTML, CSS, PHP, Javascript and SQL.The platform offers us the possibility of tracking the evolution of air parameters, in the form ofgraphs. Data can be displayed per day, per week, per month for each parameter separately (figure 5)or all on the same graph. Because the pilot project is dedicated to local use, the language used in theplatform is the local language (Romanian). In the future will be added the option by which users canchoose another international language.Figure 5: Graphical user interface – online platform3 Results and discussionsThe purpose of this paper is not the analysis of the air quality in an area of interest but thepresentation of a low-cost (table 1) air quality monitoring device that provides correct data.The data collected by the sensors are sent to a database from where they are displayed by theonline platform such that to be easy to understand for the end user.In the online platform, the user can select the period for which he wants to display the results.The results are displayed as graphs. Parameter values for one hour or several hours can be displayed(figures 6, 7, 8), for a week, a month or for a certain peri-od (figures 9, 10 for the 01.10.2019 -08.10.2019 period).https://doi.org/10.15837/ijccc.2020.4.3891 6Figure 6: NO2 values for 24h (22.10.2019 - 23.10.2019)Figure 7: PM10 values for 3h (23.10.2019)Figure 8: PM2.5 values for 3h (23.10.2019)All the parameters discussed in this paper can be displayed in this form (PM10, PM2.5, SO2,NO2, CO, O3, VOC, CO2).After 7 months of operation in real conditions and with repeated comparisons between the datacollected by these devices and data from parallel measurements with government operated air qualitystations, it can be concluded that the devices provide reliable values (figures 11, 12, 13).After mounting all devices, certain problems appeared, related to the locations select-ed initially.Due to poor air flow the results were not relevant. In the first phase, these devices were relocated, andin the second phase the number of holes on the side of these devices was increased. The measured dataclearly show that in certain periods of time the values of the air quality parameters do not complywith legal norms and concrete measures must be taken.https://doi.org/10.15837/ijccc.2020.4.3891 7Figure 9: PM2.5 values for 1 week (01.10.2019 - 08.10.2019)Figure 10: PM10 values for 1 week (01.10.2019 - 08.10.2019)Figure 11: Comparison between governments operated air quality station data and our low-cost devicesdata - NO2 values for 24h (22.10.2019 - 23.10.2019)https://doi.org/10.15837/ijccc.2020.4.3891 8Figure 12: Comparison between governments operated air quality station data and our low-cost devicesdata - PM10 values for 3h (23.10.2019)Figure 13: Comparison between governments operated air quality station data and our low-cost devicesdata - PM2.5 values for 3h (23.10.2019)https://doi.org/10.15837/ijccc.2020.4.3891 94 ConclusionsDue to the dynamic development of the city of Timisoara, in many areas, air quality problems arise(chaotic development on the real estate market, due to which the industrial platforms are located eithervery close to the residential areas or already found inside the city). Also, the car traffic is increasingnear the industrial areas. Plus, any method is welcome to follow the air quality in the industrialplatforms regarding the change of the filters in the exhaust systems.There are many established methods, but we wanted to meet the needs of the economic environmentwith a low-cost device, which can provide the same information and quality. More than necessary, ourdevices from this pilot project, can send data to the application server through LoRaWAN, withouthaving to build a complex and expensive network such as a Wi-Fi network.After this pilot project implementation, we can conclude that this air quality monitoring devicecan operate at a city scale, due to the implementation of LoRaWAN as communication protocol.Further works will focus on increasing the autonomy of the devices, so that where they will needto be mounted in places where there is no electricity supply. The existing model has autonomy only2-3 days depending on the number of readings per day.References[1] Arroyo, P.; Herrero, J.L.; Suárez, J.I.; Lozano, J. (2019). Wireless Sensor Network Combinedwith Cloud Computing for Air Quality Monitoring, Sensors, 19(3), 1–17, 2019.[2] Borrego, C.; Costa, A.M.; Ginja, J.; Amorim, M.et al. (2016). Assessment of air quality mi-crosensors versus reference methods: The EuNetAir joint exercise, Atmospheric Environment,147, 246–263, 2016.[3] Castell, N.; Dauge, F.R.; Schneider, F. et al. (2017). Can commercial low-cost sensor platformscontribute to air quality monitoring and exposure estimates?, Environment International, 99,293–302, 2017.[4] Hasenfratz, D.; Saukh, O.; Walser, C. et al. (2016). Deriving high-resolution urban air pollutionmaps using mobile sensor nodes, Pervasive and Mobile Computing, 16(B), 268–285, 2016.[5] Honeywell (2018). HPM Series Particulate Matter Sensors, Honeywell, 2018.[6] Johnston, S.J.; Basford, P.J.; Bulot, F.M.J. et al. (2019). City Scale Particulate Matter Monitor-ing Using LoRaWAN Based Air Quality IoT Devices, Sensors, 19(1), 1–20, 2019[7] Lee, S.; Lim, S. B. (2015). Applications of Ubiquitous Sensor Network: Micro-Scale Air QualityMonitoring, International Journal of Computers Communications & Control , 10(3), 370–381,2015.[8] Mo, X.; Zhang, L.; Li, H.; Qu, Z. (2019). A Novel Air Quality Early-Warning System Based onArtificial Intelligence, Environmental Research and Public Health, 16(19), 1–25, 2019.[9] Oprea, M.; Mihalache, S. F.; Popescu, M. (2017). Computational Intelligence-based PM2.5 AirPollution Forecasting, International Journal of Computers Communications & Control , 12(3),365–380, 2017.[10] Simo, A.; Barbulescu, C.; Salinschi, M. (2018). LoRaWAN based industrial emission monitoringwith self-flying drone, In 18th International Multidisciplinary Scientific GeoConference , 503–510,2018.[11] Wang, S.Y.; Zou J.J.; Chen Y.R. et al. (2018). Long-Term Performance Studies of a LoRaWAN-Based PM2.5 Application on Campus, In 87th Vehicular Technology Conference (VTC Spring) ,1–6, 2018.https://doi.org/10.15837/ijccc.2020.4.3891 10[12] Wesseling, J.; de Ruiter, H.; Blokhuis, C. et al.(2019). Development and Implementation ofa Platform for Public Information on Air Quality, Sensor Measurements, and Citizen Science,Atmosphere, 10(8), 1–20, 2019.Copyright c©2020 by the authors. Licensee Agora University, Oradea, Romania.This is an open access article distributed under the terms and conditions of the Creative CommonsAttribution-NonCommercial 4.0 International License.Journal’s webpage: http://univagora.ro/jour/index.php/ijccc/This journal is a member of, and subscribes to the principles of,the Committee on Publication Ethics (COPE).https://publicationethics.org/members/international-journal-computers-communications-and-controlCite this paper as:Simo, A.; Dzitac, S.; Frigura-Iliasa, F. M.; Musuroi, S.; Andea, P.; Meianu, D. (2020). TechnicalSolution for a Real-Time Air Quality Monitoring System, International Journal of Computers Com-munications & Control, 15(4), 3891, 2020. https://doi.org/10.15837/ijccc.2020.4.3891

Technical Solution for a Real-Time Air Quality Monitoring System

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Technical Solution for a Real-Time Air Quality Monitoring System

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