Air pollution control instrumentation

Article Index


Secondary Air Pollutants

Secondary air pollutants are produced in the air by the interaction of two or more primary pollutants or by reaction with normal atmospheric constituents, with or without photoactivation. Examples of secondary air pollutants are Ozone, Formaldehyde, PAN (peroxy acetyl nitrate), Smog) photochemical or smoke induced), Acid mist.

1.3.3 Criteria for Selection of Air Pollutants to be Covered Under The Study

Central Pollution Control Board has identified certain highly polluting industries such as cement, steel, paper, pesticides, etc. for speedy implementation of Air Pollution Control Measures. SPM, SO2, NOX, CO & Hydrocarbons are the major components of air pollution which need to be monitored. Therefore, the study covers the air pollution control instrumentation for the following pollutants/gases with special emphasis on these five major pollutants :

  • Suspended Particulate Matter
    Oxides of sulphur
    Hydrogen Sulphide
    Oxides of Nitrogen
    Hazardous & Toxic Gases
    Multi Gases

1.3.4 Type of Instruments Covered in the Study

The air pollution control instruments are based on various techniques and the following have been covered under the study :

A) Gaseous Pollutants

a) Infrared spectroscopy
b) Laser Spectroscopy
c) Ultraviolet and Visible Spectroscopy
d) Chemiluminescence’s
e) Pulsed fluorescence
f) Mass spectrometry
g) Photoionisation
h) Voltametery
i) Zirconium oxide sensor
j) Gas Chromatorgraphy
k) Colorimetry
l) Conductometry
m) Coulometry

B) Particulate Matter

a) Filter tape Sampler
b) High Volume Sampler
c) Nephelometer
d) Beta Ray Attenuation Technique
e) Transmissiometer for Opacity Measurement
f) Piezoelectric Crystal Based System
g) XRay fluorescence

1.3.5 Criteria for Selection of Instruments Covered in the Study

Based on the short list of pollutants required to be monitored as per the requirements of the Pollution Control Boards and the latest trends in the world, the short listing of equipment has been carried out. These instruments have been discussed in Chapters 4 and 6 of this study report and are listed in apra 1.6 below :


For carrying out a detailed survey in the country, questionnaires were sent to the manufacturers, users, consultants, and other agencies working in this area. Detailed discussions were then held with selected group of organizations and individuals actively involved in this area. Apart from the above, contact was made with various instrument manufacturers in developed countries like USA, UK, Germany, etc. to assess the status of technology in the world.


1.5.1 The air pollution control instrumentation industry in India is still in its infancy but steadily growing. Several instruments have been developed by the Govt. R&D institutions which have been commercialized to a limited extent. The organisations like NEERI, BARC, CSIO, etc. can further contribute in the development and growth of this industry. The major organisations in the manufacturing of air pollution control instruments in India have been Instrumentation Ltd, Kota; Rosemount Co. Ltd., Bombay; Netel Chromatograph Ltd, Bombay; SICO, Allahabad and DIL Udyog Ltd, Calcutta. The instrumentation industry has not been able to make a dent in the export market because of the inferior quality, noncompetitive prices, incompatible features and obsolete technology levels as compared to the other air pollution control instruments available in the international market.

1.5.2 Size of the Industry

The size of the Air Pollution Control Instrumentation Industry has been estimated at approx. Rs.60 Crore of which about 25% is presently being manufactured in the country. The growth of this industry has been estimated at about 15 to 20% and at this rate the total requirement in the next five years is about Rs400 crores and Rs600 crores in the next ten years. The growth rate is not expected to be linear as the development of microelectronics is reducing the cost of instruments while improving the features.

1.5.3 Technology Status

The present level of technology in the country is below international standards although the industry is aware of the latest developments in air pollution control instrumentation in the world. The reasons are

a) the instrumentation industry is dependent on the component industry which is not very developed in the country,

b) cost of developments for instrumentation is very high,

c) the govt. does not provide incentives for the use of indigenous instruments,

d) the time taken for development is so high that the instruments are already obsolete when they reach the prototype stage.


With the development of microelectronics, the international trend is on user friendly features, miniaturization, better ranges, quick responses, and development of portable models. The new instruments developed in the international fields are as given below :


  • UV Fluorescent SO2 Analyzer
    Fluorescent H2S Analyzer
    Chemiluminescent NOx Analyzer
    CO Analyzer
    Infrared Negative Absorption GFC System
    UV Photometric O3 Analyzer
    Environmental Chromatograph for Toxic Gases
    Mass Spectrometer
    Organic Vapour Meter
    Total Hydrocarbon Analyzer


Opacity Monitor
Beta Ray Attenuation Dust Monitor
Piezoelectric Crystal Based System
Sequential Air Sampler
XRay Fluorescence


  • Monitor for Combustible Gases
    Organic Vapour Meter
    Total Hydrocarbon Analyzer
    Ozone Analyzer
    Gas Chromatograph


Voltametric Sensor


Hybrid Combustion Control System
Flue Gas Measurement & Monitoring Instrumentation


Regional Network
National Network
International Network


Based on technomarket survey of Indian industry and response received from foreign organisations, it has been assessed that there are gaps in the following areas:

  • Continuous air quality monitoring.
    Continuous source/emission monitoring.
    Instruments for Toxic/Trace gases, and hazardous pollutants.
    Portable instruments including pocket type and personal monitors.
    Sensor technology.
    Computer based monitoring network and data handling systems.
    Fugitive emission monitors.
    Instrument for continuous particulate monitoring.
    Calibration/test facilities, components and accessories of monitoring instruments.
    Coordination of Research & Development activity with provision for improvement of accuracy/sensitivity of performance of instruments.
    Training of personnel for continuous air monitoring systems.
  • Following are the pollutant and analyzers where the technology gap exists :
  • Ambient / Source Environmental Monitoring
a. Gaseous Pollutants  
SO2 / H2S/NOx/NO/NH3/CO/CO2 Pulsed UV Fluorescence Analyzer
Chemiluminescence Analyzer
Gas filter correlation spectrometer
Non Dispersive Infrared Analyzer
Ozone Hydrocarbon UV photometer Analyzer
Microprocessor based Environmental
Gas chromatograph
Multigases O2 Mass Spectrometer
Zirconium oxide sensor based instrument

b. Particulate Matter

Continuous Filter tape sampler
Beta Ray attenuation monitor
Particulate mater Opacity Monitor/Transmissimeter
Insitu Dust Monitor
Emission particulate beta gauge monitor
c. In plant/Fugitive emission Monitoring CO, CO2, CH4 Multigas Analyser (Infrared Absorption
Spectroscopy and Gas filter correlation)
HC Organic vapour/ Trace gas Portable Gas chromatograph
Photoionizer/Trace gas analyzer by photoionization
d. Mercury Vapour Cold vapour atomic absorption neutron Activation analyzer
e. Formaldehyde Photoionization based formaldehyde analyzer
f. Hazardous Pollutant/ Monitor Portable Energy Dispensive
Xray Fluorescence Analyzer
Portable photoionization based Analyzer


Based on the technomarket survey, the air pollution control instrumentation industry can be divided into five categories, viz, Imported, Indigenously assembled with imported kits, Indigenously manufactured with foreign technology, Indigenously manufactured with own R&D and Agents of foreign manufactures.

The preferred options have been worked out based on the segment of the industry in which the instrument is categorized and is summarized as below:

a) Instruments where the basic technique used in India and the developed countries are the same, indigenous R&D should bridge the gap. The instruments in this category are:

  • Microprocessor based sequential air sampler
    High volume samplers
    Stack monitoring kits
    Smoke meters
    NDIR Gas Analysers
    Gas chromatorgraph
    Consumables for all samplers and analysers

b) Instruments where the techniques used abroad are sophisticated and the demand of instruments is fairly high, the technology should be imported. The instruments in this category would include the following :

  • Total HC Analysers
  • Portable Analysers
  • Automatic chemiluminescent apparatus
  • IR Analysers
  • Detector Tubes
  • Colorimetric Analysers
  • Conductometric Analysers
  • Pulsed Fluorescent Analyser

c) Instruments where the technology is sophisticated by the demands are relatively smaller the equipment should be directly imported and simultaneously Indian R & D organisations be given a specific task to develop state of art models in about 34 years time frame. The instruments in this category would include the following :


  • Beta attenuation and Peizo electric crystal based instruments for measurement of particulates
  • Personal Monitors
  • Plasma Emission Spectrometer
  • Environmental Mass Spectrometer
  • X Ray Fluorescence Analyser
  • Specific Ion Electrode
  • Photo ionization detectors

Bio sensors


The following recommendations are made to bridge the technology gap in a most cost effective manner, which will not only help the air pollution control instrumentation industry but the total instrumentation sector. As this industry is completely dependent on component manufacture the action plan will help to indigenize the instruments, make the same technically & cost wise equivalent to the comparable models abroad to give a good domestic and export market and bring the level of technology to the international status.

a) Productionisation of Monitoring Instruments in India by :

  • Identification of Instrument
  • Development and Productionisation
  • Development of Ancillaries
  • Development of Subsystems /Components

b) Setting up manufacturing units with Foreign Collaboration to ensure that the growth of the sector should be
Component based and not instrument based,
investments in the futurist technologies, and

c) Systematic policy for import of Instruments

d) Setting up infrastructure for testing and calibration of instruments

e) Setting up nodal agency for Coordination of all developmental activities

f) Ensuring the active involvement of industry by:

Improvement in quality and after sale service
undertaking not to continuously import packages/ kits but seek