USING LOW-COST SENSORS AND SYSTEMS FOR AIR POLLUTION MONITORING. Viša Tasić

Transcription

1 PRIMENA LOW-COST SENZORA I SISTEMA ZA MONITORING AEROZAGAĐENJA USING LOW-COST SENSORS AND SYSTEMS FOR AIR POLLUTION MONITORING Viša Tasić Institut za rudarstvo i metalurgiju Bor visa.tasic@irmbor.co.rs 1

2 The content of presentation: 1. The impacts of air pollution on human health 2. Methods for air pollution monitoring 3. Low-cost sensors 4. Sensor platforms with low-cost sensors 5. Calibration of low-cost gas sensors and platforms 6. Wireless sensor networks for air pollution monitoring 7. Conclusions 2

3 1. The impacts of air pollution on human health 3

4 1. The impacts of air pollution on human health People exposed to high levels of certain air pollutants (SO 2, CO, O 3, NO, NO 2, NO x, VOC, PM 10, PM 2.5 ) may experience: Irritation of the eyes, nose, and throat Wheezing, coughing, chest tightness, and breathing difficulties Worsening of existing lung and heart problems, such as asthma Increased risk of heart attack Long-term exposure to air pollution can cause cancer and damage to the immune, neurological, reproductive, and respiratory systems. In extreme cases, it can even cause death. 4

5 1. The impacts of air pollution on human health Example : Deposition of PM in the respiratory organs by inhalation Suspended particles: PM10 - less than 10 µm in diameter PM2.5 - less than 2.5 µm in diameter PM1 - less than 1 µm in diameter 5

6 1. The impacts of air pollution on human health Suspended particles (TSP, PM10, PM2.5, PM1) may contain: As, Cd, Ni, Pb According to International Agency for Research on Cancer (IARC) substances as: Inorganic As, Cd and Cd compounds, and Ni compounds are classified as carcinogens to humans (group 1); Pb compounds are classified as probably carcinogenic to humans, (group 2A); Pb and Ni and alloys are defined as possibly carcinogenic to humans (group 2B); 6

7 2. Methods for air pollution monitoring 7

8 2. Methods for air pollution monitoring Automatic monitoring methods (continual) Semi-automatic and manual monitoring methods (discontinual) Both methods are in use for air pollution monitoring in the: National network of Air Quality Monitoring (AQM) stations Local network of AQM stations (Municipality level) 8

9 2. Methods for air pollution monitoring Automatic AQM Networks in the Republic of Serbia - National network of AQM stations, operated by (SEPA) Serbian Environmental Protection Agency - Local networks of AQM stations, operated by local municipalities > 30 fixed AQM stations Reference gas analysers for: SO 2, CO, O 3, NO, NO 2, NO x, VOC, 2 mobile stations Reference equivalent analysers for: PM 10, PM 2.5

10 2. Methods for air pollution monitoring National network of automatic AQM stations Advantages: - Certified reference instruments - Strict maintenance and calibration procedures - High quality data - Data comparability between AQM stations and regions Disadvantages: - High costs of installation and maintenance - High power consumption - Sparce monitoring (limited number of AQM statios) 10

11 3. Low-cost sensors The coverage area of National AQM system is limited, so that, usually unable to present actual situation of air pollution in the wider area. As an alternative to the conventional method, air pollution monitoring system with low manufacturing cost and high mobility is therefore needed to be developed to compensate the shortcomings of conventional AQM systems. 11

12 3. Low-cost sensors A sensor is a device that detects and responds to some type of input from the physical environment. The output is a signal that can be transmitted electronically over a network for reading or further processing. 12

13 3. Low-cost sensors The idea is to cover the area of interest with a dense network of sensor nodes that are able to produce enough data about the air pollutant of interest. 13

14 3. Low-cost sensors Reference instruments costs: EUR Low-cost sensor costs: EUR 14

15 3. Low-cost sensors We need low-cost sensors for measuring traffic emissions: CO, NO 2, VOC, PM 10, PM 2.5 Gas sensors: - Electrochemical - Solid-state (metal-oxide) - Optical - Gravimetric - Catalytic - Based on MOS structures PM sensors: - Optical 15

16 3. Low-cost sensors Metal-oxide Metal-oxide Metal-oxide Electrochemical SnO 2 SnO 2 Low-cost gas sensor costs: EUR

17 3. Low-cost sensors Sharp GP2Y EUR Alphasense OPC N1 100 EUR Dylos DC EUR PM optical particle counter costs: EUR

18 Sharp GP2Y EUR 3. Low-cost sensors

19 3. Low-cost sensors Sharp GP2Y1010 We need additional hardware and software to be able to use (connect) low-cost sensors. We need sensor platform (sensor node).

20 4. Sensor platforms with low-cost sensors

21 4. Sensor platforms with low-cost sensors Sensor platform (Sensor Node) usually consists of : Sensor board (one or more sensors) Control board (microcontroller, external memory) Communicaton module (USB, GPS/GPRS, WiFi) Power supply module (AC/DC, baterry, solar panel) Low-cost sensor platform (cost less than 1000 EUR)

22 4. Sensor platforms with low-cost sensors

23 5. Calibration of low-cost gas sensors and platforms Calibration issues - The lack of standards for evaluation and validation of sensors - Lack of information about sensor and platform characteristics (accuracy, stability), - Temperature or humidity drift, - Baseline drift (differences between laboratory and field calibration), - Cross-sensitivity (chemical interference, for example NO 2 with O 3 ). Calibration in the laboratory (controlled conditions) Injection of specific mixtures of gas standards into a chamber that is equipped with T and RH control. Field calibration (real conditions) Co-location the sensor platforms near the AQM station

24 5. Calibration of low-cost gas sensors and platforms Calibration in the laboratory: Injection of specific mixtures of gas standards into a chamber that is equipped with T and RH control.

25 5. Calibration of low-cost gas sensors and platforms Example of calibration issues: NO 2 cross sensitivity to O 3

26 6. Wireless sensor networks for air pollution monitoring The rapid development of Wireless Sensor Networks (WSNs) has led to developing AQM systems which are: - Cost effective, - With low energy consumption, - Low installation and maintenance costs, - Quick and easily reconfigurable. The devices for wireless networking of small range (Bluetooth and ZigBee) are especially suitable, as well as mobile phone systems for greater range, such as GSM/GRPS 26

27 6. Wireless sensor networks for air pollution monitoring 27

28 6. Wireless sensor networks for air pollution monitoring Air pollution information is available through web pages, Web Apps, mobile Apps, etc. 28

29 6. Wireless sensor networks for air pollution monitoring Static Sensor Network (SSN) The sensor nodes are typically mounted on the streetlight or traffic light poles, or walls. Air pollution information with high spatio-temporal resolution is achievable. Community Sensor Network (CSN) The sensor nodes are typically carried by the users. By utilizing the low-cost portable ambient sensors and the ubiquitous smart phones, users are able to acquire, analyze and share the local air pollution information. Vehicle Sensor Network (VSN) The sensor nodes are typically carried by the public transportations like buses or taxis. By utilizing the low-cost portable ambient sensors and the mobility of vehicles, one sensor node is able to achieve sufficient large geographic coverage.

30 7. Conclusions - The conventional method of AQM is based on a limited number of stations. This method is very expensive and the collected data do not cover large areas. - As an alternative, AQM system with low-cost sensors is therefore needed. - But, prior to installation, the AQM system with low-cost sensors should pass appropriate quality assurance and control procedures, in the lab conditions, as well as, in the field. 30

31 7. Conclusions - New communication technologies enabled the implementation of WSN for air quality monitoring. - Due to low power consumption and simple configuration ZigBee WSNs are the most commonly applied WSNs for air quality monitoring. - In the near future, information on air quality will be available to all citizens in real time. - This task will be solved by using WSNs for AQM with low-cost sensors that will complement the existing national and local AQM systems. 31

32 Thank you for your patience! 32