Sensor-based air quality monitoring instruments left out of new certification scheme

The notification gives CSIR-NPL the authority to certify instruments but fails to address the certification of low-cost instruments

By Digvijay Singh Bisht
Published: Friday 30 August 2019

The Ministry of Environment, Forest and Climate Change (MoEFCC) recently designated the Council of Scientific and Industrial Research-National Physical Laboratory (CSIR-NPL) as a national agency that shall be responsible for carrying out certification for instruments and equipments for monitoring emissions and ambient air.

The ministry issued a notification on August 22 under Section 3 of the Environment Protection Act, giving CSIR-NPL the authority to certify instruments. The aim is to have a check on the quality of instruments and data. The development comes in the backdrop of the National Clean Air Programme (NCAP), released in January 2019 by the environment ministry.

“This is a positive move and will bring uniformity in the instruments that are currently being used for regulatory grade monitoring through enhanced scrutiny on instrument design and performance, and that will address issues related to data quality,” said Rajendra Prasad, chief executive, Ecotech Instruments, which manufactures air-quality measuring instruments.

These days many low quality instruments are flooding the market and thereis no basis to choose the right product. In most cases, the design of the instruments deviate from the standard given by the US Environmental Protection Agency (EPA). Therefore, with the help of this notification, NPL will be able to test all instruments that are floating in the market and issue a certificate only if their specificationsmeet the quality standard. This will foster user confidence in the product, its design, its calibration and its data quality. 

Why the certification?

“Most of the instrument used for Continuous Ambient Air Quality Monitoring Stations (CAQMS) and Continuous Emission Monitoring Systems (CEMS) are imported and come with their respective certifications that have been issued by agencies such as the EPA, Technischer Überwachungsverein (TUV), Monitoring Certification Scheme (MCERTS); based on the environmental conditions of the country issuing the certificate,” says JS Kamyotra, former member-secretary, Central Pollution Control Board (CPCB).

“Their certification is not based on the climatic and environmental conditions that are prevalent across India. Designating CSIR-NPL as a verification agency will help in performance optimisation of equipments for the Indian environmental and meteorological conditions. This will also encourage Indian manufacturers to develop instruments, promoting ‘Made in India’,” he added, underscoring that “this is in harmony with commitments made in NCAP”.

According to the NCAP report, one of its main objectives is “to augment and evolve effective and proficient ambient air quality monitoring network across the country for ensuring a comprehensive and reliable database.”

The document also states that “CSIR-NPL proposes to establish an NPL-India Certification Scheme (NPL-ICS) to cater to the country’s needs in respect of Online Continuous Emission Monitoring System (OCEMS), Continuous Ambient Air Quality Monitoring System (CAAQMS), and PM2.5/PM10 samplers.” This is also mentioned in the new notification.


Under the current directions of the notification, CSIR-NPL will have to develop necessary infrastructure, management systems, testing and certification facilities that are conformant to standards like ISO 17065 and ISO 17025 for both manual samplers and CAQMS, in addition to CEMS.

In addition to this, NPL has also been tasked with the responsibility of preparing all documentation and protocol for measurement, in consultation with the CPCB. As most of the protocols for the listed technologies are available and being used internationally, it should not be very challenging to develop the Indian equivalent for these and design the certification system in a way that is suitable for the Indian conditions.

As per the NCAP, the proposed certification scheme will have three major components — NPL-India certification body (NICB), certification committee and testing and calibration facility. The NICB will be the highest body with five members, including the chairman, member secretary, and the three expert members, one each from the CSIR-NPL, CPCB and National Environmental Engineering & Research Institute (NEERI).

The second component, which is the certification committee, will be consisting of seven members (four permanent and three co-opted). The three co-opted members must be associated with independent institutes or organisations like the Indian Institute of Technology (IIT), National Accreditation Board for Testing and Calibration Laboratories (NABL), or other academic institutes as per the required technical/academic expertise on case to case basis.

The third component, which will be the heart of this scheme, will provide the required test reports. The facility will be fully capable for testing and calibrating extractive, in-stack, or cross-stack measurements to allow more than one system to be tested at a time as per the test programme generated by the certification committee. The proposed facility will allow testing of OCEMS, CAAQMS and data-handling systems (DAHS), besides other air pollution monitoring equipment such as PM2.5 and PM10 samplers.

Other than this, the proposed testing and calibration facility will also be capable of conducting three months of field testing as per the requirement of the European Standard EN-15267-3 (which is the stationary source emissions-quality assurance of automated measuring systems or Indian equivalent) and Quality Assurance Level-3 (QAL-3) of European Standard EN-14181 or Indian equivalent.

As per an industry insider, NPL is currently in the process of readying itself to be completely equipped for carrying out the certification process. For the air quality monitoring equipment, NPL will take a minimum of 6 months to do the first batch.

Sensor-based instruments 

“Since the enactment of the Air (Prevention and Control) Act, 1981, we have only been able to deploy around 700 air quality monitoring stations in the country (including continuous as well as manual). However, the need is to have about 3,000 stations.

“Therefore, as I see it, there is ample scope for augmenting the current monitoring network with low-cost sensor technologies. And the current notification could have been used as a means to develop the certification system for low-cost sensor technology also,” according to DD Basu, former Additional Director, CPCB.

According to a senior official from MoEFCC, the uses of low-cost sensor based instruments are currently tabled, however, currently, there aren’t any guidelines or protocols based on which a certification system can be developed for them. Organization like Bureau of Indian Standards (BIS) in consultation with other competent agencies have to come up with some benchmark or specifications, only then MoEFCC will be able to take it forward. 

The emphasis of the development of the sensor-based instrument is relevant to ensure detailed spatial and temporal coverage. Under the NCAP, even if the government plans to invest more in establishing an elaborated air quality monitoring network of standard instruments, the lack of financial capital and manpower will be a major challenge to the vision of a widespread coverage across all the non-attainment cities.

Therefore, in order to complement the planned network, the use of sensor-based instruments is crucial, and to make that possible so that the data generated is reliable, the certification for these sensor-based devices must swiftly follow the one for the standard instruments. Hybrid networks are going to be the future of monitoring and will help the government take better decisions in terms of network design and cost-effectiveness.


Merits of having a certification process

Improved enforcement of emission monitoring across industries

In terms of the emission monitoring, as per the government direction, all the red-category industries have installed CEMS. However, the direction is silent on the kind of CEMS instrument to be installed. And since CEMS instruments range from a few lakhs to a few crores, the industry always goes for the cheapest option, which fails to meet the very purpose of installing CEMS.

This will help in evaluating the performance of all the CEMS instruments in the market for a better understanding of their performance, which will help in the better implementation of this technology in the industry as well as help the regulators in the enforcement of the technology throughout the industry.

Better data quality

Since most of these instruments are imported their suitability to the Indian conditions have been an area of debate. Therefore, with in-house certification, instruments can now be tested and their performance evaluated and verified within the country. Reliability and performance of instruments can be checked and issues addressed.

With domestic certification in place, the instruments will perform better under Indian conditions and therefore, will have better data quality — promoting better policy decisions.   

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