2.0 AIR POLLUTION MONITORING

2.1 Current Monitoring Network

As an integral part of the air pollution control programme, CPCB has established a national network of ambient air quality monitoring stations. This nation-wide programme, called the National Ambient Air Quality Monitoring (NAAQM) was launched in 1984 with a network of 28 monitoring stations covering 7 cities. Over the years, the number of stations have increased and presently, the network comprises 290 stations spread over 92 cities/towns distributed over 24 stations and 4 UTs. In addition to the NAAQM programme, operated by CPCB, many State Boards have set up Ambient air quality monitoring stations under their own programme known as Ambient Air Quality Monitoring (AAQM) programme. National Environmental Engineering Research Institute (NEERI) monitors ambient air quality in 30 stations covering 10 major cities. In addition to the monitoring stations, operated by the Central/State Boards and Research Organisations, major industries have set up monitoring stations as part of the compliance of the consent conditions. The location of the monitoring stations established under NAAQM programme are depicted in Figure – 1.

The pollutants monitored at NAAQM/AAQM stations are NO2, SO2, SPM besides meteorological parameters like wind speed, wind direction, temperature and humidity. In addition to these three conventional parameters, NEERI monitors special parameters like NH3, H2S, RSPM, PAH and heavy metals. CPCB has initiated monitoring of particulate lead, PAH, heavy metals, ozone and CO at some of its monitoring stations in Delhi. The objectives of the air quality monitoring programme are : - to strengthen the existing air monitoring system with the adoption of state-of-the-art methodologies to monitor the air quality;

- to monitor the criteria pollutants depending on the locations;

- to determine present air quality status and trend;

- to provide background air quality data as need for industrial siting and town planing; and

- to control and regulate pollution from industries and other sources to meet the air quality standards.
 
    1. Monitoring Agencies
The National Ambient Air Quality Monitoring (NAAQM) programme being a nation-wide network, several agencies are involved in the activities. These are:
  - Central Pollution Control Board (CPCB) in the city of Delhi;

- State Pollution Control Boards (SPCBs) in the respective states;

- Pollution Control Committees (PCCs) in the respective UTs;

- National Environmental Engineering Research Institute (NEERI), Nagpur in 10 metro cities of the country;

- Vishveshvaraiya Regional College of Engineering, Nagpur in the city of Nagpur;

- University of Pune in the city of Pune;

- KTHM College, Nasik in the city of Nasik; and

- Walchand Institute of Technology, Solapur in the city of Solapur.
 

 CPCB coordinates with these agencies to ensure the uniformity, consistency and compatibility of air quality data and provides technical and financial support to them for operating the monitoring stations. The methods of measurement for the criteria pollutants are identified in the ambient air quality standards laid down by CPCB under Section 16(2)(h) of the Air Act, 1981 and notified (Table – 2.1) for various air pollutants, i.e. SO2, NOx, SPM, RSPM, Respirable lead and CO. The areas have been categorised as industrial, residential and sensitive These standards provide the basis for protecting the public health from adverse effects of air pollutants and limiting those contaminants of air within the adequate margin of safety. Table - 2.1 : Pollutants Monitored at the NAAQM Stations
S.No.
Parameter
Monitoring Method/Technique
1
 SPM High Volume Sampler Method
2
 RSPM High Volume Sampler Method (attached with cyclone) 
3
 SO2 Colorimetry (Modified West & Gaeke)
4
 NO2 Colorimetry (Modified Jacob & Hochheiser Method)
5
 CO Non-Dispersive Infrared Spectroscopy (NDIR)
6
 Pb Acid Digestion Of Exposed Filters Followed By AAS Analysis
7
 PAH Solvent Extraction of Exposed Filters Followed By Estimation 

With GC - FID 
8
 H2S Colorimetry (Cadmium Sulphate - ST Ractan Method)
9
 NH3 Colorimetry (Indophenol Method)
The air quality data obtained from these monitoring stations is compiled in a report annually and published for the use of policy makers, researchers and general public. 2.3 Siting of Monitoring Stations The air quality monitoring programmes are needed for almost of the actions taken to prevent/abate air pollution from the initial assessment of existing conditions to the enforcement of current control regulations to the evaluation of the effectiveness of abatement programmes and finally to the development of new control measures. The criteria laid down in the WHO publications, 1977, entitled the, "Air Monitoring Programme, Design for Urban and Industrial Areas have been used for establishing the ambient air quality monitoring network under the NAAQM Programme in India. The criteria guidelines as a whole could not be followed at few places keeping into the view, the location limitations. The following requirements have also been considered while identifying the status for the monitoring sites. - These stations are more of logistic in nature to cover the max. representative site which is exposed to the polluted air.   - Availability of space for monitoring.

- Availability of       :     Water
Infrastructure         :     Electricity
in the field             .     Transport
        .     Sampling and preservation
- Height of the Site 3 to 5 metre's

- Stations are fixed at sited locations and they are manually operated.

    - In Delhi some       :      Semi automatic
    of them are            .       Manual
  1. Monitoring Results

    2.  

     

    The monitoring data for 1998 received from various agencies have been analysed and results are shown below for average values on 24 hours and Annual basis respectively.

    In case of SPM, there is a 100% violation for five stations details of which are given in Table 2.2

    Table 2.2 : Average Concentration of SPM on 24 hourly basis for 100% violating stations
    S.No. Location
    Type
    		 Total No. of Observations No. of Observations violating the Norms
    1.
    		 Taj Mahal, Agra (U.P.)
    S
    285
    285
    2.
    		 R.O. Bodla, Agra (U.P.)
    R
    80
    80
    3.
    		 Deputy Ka Parao, Kanpur (U.P.)
    R
    79
    79
    4.
    		 Kapoor Hotel, Hazratganj, Lucknow (U.P.)
    R
    92
    92
    5.
    		 Mahanagar, Lucknow
    R
    88
    88

    In case of NOx, the highest violation is 28% and top four violations (above 20%) are given below: (Table 2.3)

    Table 2.3: Average Concentration of NOx on 24 hourly basis where violation is more than 20%
    S.No. Location
    Type
    		 Total No. of Observations No. of Observ
    ations violating the Norms    		 Percent-age of Violation
    1.
    		 Barkhera, Kota (Rajasthan)
    S
    90
    25
    28
    2.
    		 Town Hall, Udaipur (Rajasthan)
    R
    65
    17
    26
    3.
    		 R.C. High School, Ahmedabad (Gujarat)
    R
    54
    12
    22
    4.
    		 R.O. Dhanbad (Bihar)
    R
    85
    17
    20

    In case of SO2, the highest violation is 31% and the details of violations which are more than 20% are given below: (Table 2.4)

    Table 2.4 : Average Concentration of SO2 on 24 hourly basis where violation is more than 20%
    S.No. Location
    Type
    		 Total No. of Observations No. of Observations violating the Norms Percentage of Violation
    1.
    		 PIPDIC Indl. Estate, Mettupalayam (Pondicherry)
    I
    77
    24
    31
    2.
    		 R.O. Dhanbad (Bihar)
    R
    85
    23
    27
    3.
    		 Grasim Kalyan Kendra Nagda (M.P.)
    R
    94
    19
    20

    For SO2, there is a violation of standard at two residential areas (viz. R.O., Dhanbad in Bihar and Sub Regional office, Bapa Nagar, Charapaur in Maharashtra) and two industrial areas (viz. PIPDIC Indl. Estate Mettupalayam in Pondicherry and M.A. D.A. Jharia in Bihar.(Table 2.5)

    Table 2.5 : Average Concentration of SO2 on Annual basis violating Norms
    S.No. Location
    Type
    		 Concentration of NOx (m g/m3)
    1.
    		 PIPDC Indl. Estate, Mettupalayam (Pondicherry)
    I
    116.6
    2.
    		 R.O. Dhanbad (Bihar)
    R
    68/1
    3.
    		 M.A.D.A., Jharia (Bihar)
    I
    80.7
    4.
    		 Sub-Regional Office, Bapat Nagar, Chandrapur (Maharsthra)
    R
    61.0

    In case of Oxides of Nitrogen, there is violation at seven locations (on annual basis) out of which one is sensitive and three each in residential and industrial areas. These locations are given in Table 2.6

    Table 2.6: Average Concentration of NOx on Annual basis violating Norms
    S.No. Location
    Type
    		 Concentration of SO2 (m g/m3)
    1.
    		 PIPDIC Indl. Estate, Mettupalayam (Pondicherry)
    I
    81.0
    2.
    		 Barkhera, Kota (Rajasthan)
    S
    26.3
    3.
    		 Regional Office, Alwar (Rajasthan)
    R
    75.1
    4.
    		 Regional Office, Udaipur (Rajasthan)
    R
    60.4
    5.
    		 Town Hall, Udaipur (Rajasthan)
    R
    71.7
    6.
    		 DIC, Udaipur (Rajasthan)
    I
    81.6
    7.
    		 RIICO Pump House, Alwar (Rajasthan)
    I
    80.3

    In case of SPM (Average Annual basis), there is violation at 73 locations out of which two locations are sensitive (i.e. Barkhera; Kota [Rajasthan]; Taj Mahal, Agra [U.P.]). 13 industrial and remaining 59 located in Residential Areas.
     

  2. Data Availability
The monitoring data is submitted to CPCB by agencies, responsible for operation of the National Ambient Air Quality Monitoring (NAAQM) stations every month. The raw data is collated, compiled, interpreted and analysed at CPCB. The analysed data is compiled in the form of report or Ambient Air Quality Status and Statistics and published every year.

The monthly air quality data for Delhi is compiled and made available on Internet. The regular air quality reports of the monitoring data in Delhi are published.

Yearly data of the stations under the NAAQM programme is also provided on Internet. The data is made available to all the users whenever asked for.

 2.6 Data Quality Checks In order to ensure that the quality of monitoring data, obtained from the network, is acceptable, regular plausibility control and the evaluation of the monitoring data is undertaken. CPCB has been collected data from its network of ambient air quality monitoring data is undertaken.

CPCB has been collecting data from its network of ambient quality monitoring stations, established under the NAAQM Programme. The quality and reliability of data vary from city to city and state to state, thereby making it difficult to complete the different levels of the data, obtained from the network. In order to improve the reliability and precision of the data, collected, quality assurance and quality control needs to be introduced in the system. CPCB with the assistance from German counterpart has developed Calibration Laboratory with In-house facilities to produce the primary and secondary standards. The facilities are being utilised to impart training to State Boards’ officials for quality control and quality assurance. Facilities are also being used to ensure uniformity in the Analytical procedure and standardisation of the procedure. The present available facility is not adequate enough to meet the requirement in the entire country. Considering the importance of quality control proposal for developing facilities for quality control in ring test at more places has been formulated.

 2.7 Future Approach The industrial scenario in India today, can aptly be summarised, as one which is capital intensive and energy-oriented. The industrial growth in India has shown phenomenal increase over the last decade and in almost all sectors. Excepting for a few major industries, there is no serious effort made for emissions and/or in-plant monitoring.

The ambient air quality measurements are restricted to specific areas due to practical constraints. Mostly conventional liquid scrubbing techniques are being employed. Although these methods are still valid, it is fair to point out that most analytical methods are manpower intensive and sometime lack in specificity and precision in comparison to automatic method.

Certain sensitive parameters, like ozone, cannot be monitored or assessed reliably using manual monitoring techniques. The manual monitoring techniques cannot depict the maximum and minimum concentration as averaging of the pollutants is done over a period of 4-8 hours depending upon the prevailing concentration. The chemical methods are also not well established to monitor low as well as high level concentration. The acceptability of any method should have to be commensurate with both ambient air quality standards and emission standards.

The classical method of sampling and analysis for criteria pollutants and a few specific pollutants are slowly being replaced by on-line instrumental techniques. In the instrumental system for pollution monitoring, the pollutants either undergo a mechanical reaction, or physical property is used to generate output which is converted into an electrical signal which includes chemiluminiscence, fluorescence, electrochemical reaction, flame ionisation, flame photometry, infra-red absorption, catalytic oxidation etc..

Keeping the above into consideration, the need to upgrade the monitoring programme was increasingly being felt for a long period. With this objective, CPCB installed two continuous monitoring stations (fixed) and procured two mobile vans on experimental basis for assessing the ambient air quality. These stations were received under the Indo-EEC and Indo-German bilateral project. CPCB has been operating these stations for the last 10 years. In the beginning, many problems were encountered in making the stations operational, which were related mostly to the peripheral systems as the complete package of the stations was imported. Most of the problems encountered during initial operation were resolved with assistance from the German counterpart in the Indo-German project. This helped CPCB to develop expertise required for operation, maintenance and repairing of the systems. All the technical staff working on the project have been provided on-the-job training abroad. In addition, considering the problems in calibration of the analysers, CPCB with the assistance from the German counterpart have developed calibration laboratory with in-house facilities to produce primary and secondary standards. The available expertise and infrastructure in CPCB is being utilised to provide necessary guidance to other State Pollution Control Boards and public/private sectors which have installed such continuous monitoring stations are in the process of doing so. With the increase in diversification in the nature of pollutants, it is proposed to monitor continuously parameters, like ozone (O3), carbon monoxide (CO), respirable particulate matter (PM10) and hydrocarbon (HC) alongwith criteria pollutants, like SO2, NO2 and SPM.

No air monitoring programme is completed without the measurement of wind speed, wind direction, temperature and relative humidity. These parameters primarily help to quantify atmospheric characteristics, like pollutant transport and diffusion.