Introducing Low Cost Sensor Monitoring: Improving the Performance of the National Ambient Air Quality Network (NAAQMN)

15th Air Quality Governance Lekgotla

Session 1.3

Premier Hotel, Kempton Park, Gauteng

04 – 06 October 2021, MS Teams Meeting

Objective of Presentation

• To share a common understanding on DFFE low-cost sensor monitoring initiative that is designed to complement the National Ambient Air Quality Monitoring Network reference monitoring

• DFFE is undertaking this initiative to lead in the introduction of the technology taking cognisance of the growing international opportunities and advancements of using low-cost sensors in air quality monitoring (and acknowledging the limitations)

Presentation Outline

• NAAQMN operation and status

• What are alternative air quality monitoring techniques?

• Why low-cost sensor monitoring?

• Low-cost sensor opportunities and challenges

• Introducing sensors to the NAAQMN• Proposed classification of stations based on measurement technologies• DFFE proposed low cost sensor monitoring plan

• Way forward

National Ambient Air Quality Monitoring

Network – NAAQMN

• There are currently 135government owned stations

• Out of these 101 stations are reporting LIVE to SAAQIS

• Less than 50% of stations are meeting data requirements

Challenges with NAAQMN

• Poor operation and data recovery of monitoring stations due to:• Resourcing of the NAAQMN (finance, personnel and infrastructure)

• Supply chain challenges – both from authority and suppliers of equipment

• Power supply – load shedding and interrupted supply due to disconnections

• Security – vandalism of equipment

• Technical capacity of personnel to manage stations effectively

• Decentralised system of managing monitoring stations across the country – expensive, ineffective, inefficient and uncoordinated

Status of NAAQMN Functionality – 2020 Annual Data Recovery

AQ Governance Lekgotla 2019 ResolutionApproach for Future Stations Management

• In view of challenges identified as we as the prohibitive costs of maintaining stations, it is recommended that the following approach be considered: • Government maintains the current NAAQM and keeps it functional and

meeting minimum data requirements – as these are already heavy investments – BUT have a moratorium on the procurement of new continuous monitoring stations.

• There are low-cost devices with far less maintenance requirements gov. can purchase and install in areas where there is no monitoring.

• Only in the event that low cost monitors record high levels of pollutants –necessary investments on instruments that constitute approved methods for reporting compliance may then be purchased and installed

Follow-up to AQ Governance Lekgotla 2019 Resolution

• Following the resolution, DFFE started ground work on alternative monitoring

• Multi-stakeholder workshop on 27 February 2020• Sensor suppliers presented on performance of sensors and monitoring matrix

• Discussions on how sensors could be introduced to SA as a tool to support the NAAQMN and increase citizen awareness on air quality

• Low-cost sensor toolbox – support for sensor users and operators

• Reference laboratory for sensor comparison with reference methods

• Then there was COVID lockdown and further engagements stalled

MINTECH - Working Group II

MINMEC requested WGII to provide options for NAAQMN recapitalisationand modernisation in order to improve monitoring performance

• Held Working Group II Technical Meeting on 15 July 2021

• WGII workshop was followed by the NAAQMN Tech Committee meeting on 16 July 2021

• Both meeting were meant for DFFE to introduce a proposal for introducing low cost sensors to the NAAQMN• Responses from authorities were mixed – Wednesday workshop

• Not enough clarity on the implications to the NAAQMN and authority roles in ambient monitoring – presentation on legal framework

What are Alternative Air Quality Monitoring Techniques Available?

• Low Cost Sensors/Electrochemical samplers /Air Sensors/ Micro sensors

• Passive sampling

• MiniVol samplers (only for particulate matter)

• Compact analysers – smaller versions of reference instruments

• Remote Sensing

• Photochemical/dispersion/ predictive modelling

Low-Cost Sensor Opportunities and Challenges

Opportunities

• Portable, compact and affordable air quality monitoring technologies that can be deployed in practical timeframes in order to speedily supplement the NAAQMN and address some of the immediate challenges

• Provide real time measurements at lower cost - cheap to commission and operate

• Easy to operate – no need for skilled operators to manage and calibrate

• Operate with limited human intervention for long periods

• Easily to secure – reducing risks of vandalism/theft

• Can be powered by solar – reducing electricity challenges

• Versatile measurement matrix – multiple pollutants

Challenges

• Developing technology and some users reluctant to introduce into AQM practices

• Limited exhaustive and accessible information to compare the performance of low-cost sensors and the wide commercial offerings

• Makes it difficult to select the most appropriate low-cost sensors for monitoring purposes

Implications of Introducing Low Cost Sensors to NAAQMN

NAAQMN Station Classification

• Introducing low-cost sensors requires a relook at the NAAQMN and the way monitoring stations objectives are defined

• A classification of stations based on monitoring objectives

• NAQI stations – national core stations measuring the efficacy of AQM interventions across the country

• Priority Area stations – national priority areas as is prescribed by legislation

• Hybrid stations – those using a combination of monitoring technologies

• Low-cost sensor monitoring legal framework

Alternative Monitoring

Stations

Hybrid –Alternative &

Reference Stations

Priority Areas

Stations (15)

NAQI Stations

(39)

Proposed Approach – NAAQMN Station ClassificationsStation

ClassificationObjective Monitoring Approach Other Operating Requirements

NAQI Stations Monitoring to inform the NationalAir Quality Indicator and long-term national interventions

Reference Monitoring Expensive monitoring requiring sustainable funding

Priority Areas Monitoring to inform the priority areas interventions

Reference Monitoring Expensive monitoring requiring sustainable funding

Local Strategic Station

Monitoring to inform localised interventions

Reference Monitoring Expensive monitoring requiring sustainable funding

Hybrid Stations Monitoring air for reporting andscreening purposes

Combination of reference and alternative techniques monitoring depending on objective

Use of reference monitoringcould be confined to PM to reduce costs

AlternativeMonitoring Stations

Monitoring for screening purposes

Alternative Monitoring Reference monitoring to be considered when there is noncompliance with NAAQS

Approach to Introducing Low-Cost Sensor Monitoring to the NAAQMN

Proposed Approach to the NAAQMN

• Following July/August WGII engagements

• DFFE has secured possible funding for low-cost sensors

• Prepared a Low-cost sensor monitoring plan• Station Classifications

• Selected stations in the NAAQMN for possible commissioning of sensors

• Developed a program for sensor maintenance and data reporting

• Initiated the procurement process

NAAQMN Low-Cost Sensor Monitoring

Establish a low-cost sensor monitoring network to complement the national monitoring• Instead of recapitalising the stations with new analysers, low-cost sensors

could be considered• For monitoring criteria gases – use low cost sensors • Reserve reference monitoring for particulate matter• This is because most low cost sensors are most effective at monitoring gasses, but

not particulate matter (in general, low-cost sensors underestimate particulate matter)

• This approach will significantly reduce the costs of running NAAQM (both in finances, logistics and personnel)

• The approach is in line with best international practices – redesigning monitoring networks and substituting expensive monitoring technologies

Low-Cost NAAQMN Stations Commissioning Timeframe

Identifying stranded stations & those with non-functional analysers and redesign requirements – August 2021

Establish a national program to introduce low cost sensor monitoring into the NAAQMN – October 2021

DFFE procurement of low-cost sensors and commissioning – December 2021

Recapitalisation of PM instruments at other stations –September 2022??

Station Identified for Low-Cost Sensor Monitoring

Consider station performance (2020 and 2021) based on the station functionality report

Most stations are residential and industrial sites

Ensuring national coverage and security

Identified 32 stations across the country

(30 existing and 2 new stations in Northern Cape)

32 stations selected –further analyses on why the stations are not performing to full capacity

Consider co-location of analyzers across the country for performance analyses

Full analyses of low-cost sensor performance after the colocation period (say 6months including the winter)

Station Identified for Low-Cost

Sensor Monitoring

Station Type

Province Industrial Residential Traffic Urban Total

Sensors

EC 1 2 3

FS 1 1

GP 4 4 1 1 9

KZN 4 1 5

LP 2 2

MP 1 1

NW 1 2 1 4

NC 2 2

WC 2 1 3 6

Total 13 10 1 8 32

Station Identified for Low-Cost Sensor Monitoring

Station Identified for Low-Cost Sensor Monitoring

Parameters to be Measured

Air Pollutants

• Sulphur dioxide

• Nitrogen dioxide

• Ozone

• Carbon monoxide

• Particulate matter (PM10 and PM2.5)

• Hydrogen sulphide

Meteorological Parameters

• Ambient temperature

• Ambient pressure

• Met monitoring is rather optional on some of the sensors

Sensor Installation and Commissioning

• DFFE will engage with network owners on the installation of sensors once the type of sensor to be procured is established

• Engagements to consider matter such as power supply, security, access to site, and the feasibility of adding the sensor onto the infrastructure

• For NC, engagements will be on site location and logistics as these are new

• Sensors will be commissioned at all stations as soon as they are procured

• Once installed and commissioned, sensors must calibrated and monitored for performance for at least 30 days and reported as part of sensor commissioning

• All sensors will be commissioned for LIVE reporting to SAAQIS

Sensor Management, Maintenance & Data Reporting

• Sensor Maintenance and Repair• The supplier will be required to include a technical support plan for as long as

the sensors warranties stand as well as a sensor maintenance plan for the period of five years.

• Regular calibration and basic upkeep will be in line with manufacturer specifications

• Noting that low-cost sensors are generally low maintenance instruments

• Considerations will be made for replacement of malfunctioning sensors

Sensor Performance Monitoring

• A calibration program will be established as part of technical support

• Take into account data correction principles due to the changes in meteorological conditions (such as relative humidity and ambient temperature) as well as possible changes in seasonal composition of atmospheric pollutants, especially particulate matter.

• Corrections of data to ensure accurate data are reported to the public

• This will require that some reference monitors CONTINUE at the sensor stations, for assessment of sensors against reference monitoring methods for a period of at least 6 months (co-location) –discuss ??

Sensor Data Management and Reporting

• DFFE will be responsible for:• Conducting daily check of sensor data on SAAQIS to ensure that all

sensors are operating optimally. Where sensor faults are identified, these will be reported to the service provider for further investigations and technical support

• Ensuring that current and accurate data from all sensors are readily available to the public through SAAQIS.

• Conducting data quality control and quality assurance monthly.

• Preparing detailed air quality monitoring monthly reports at provincial levels to be share with stakeholders via SAAQIS

Way Forward

• Procurement process underway

• Once advanced, DFFE will initiate engagements with network owners as per plan

• SAWS to establish a laboratory for sensor comparisons with reference methods – engagements initiated with SAWS

• Comparisons as well as DFFE roll-out will influence the guidance to be provided

• Encourage more sensor comparisons to built a national inventory and assist with guidance development

Thank You

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Department of Forestry, Fisheries and the EnvironmentChief Directorate: Air Quality Management