Central Pollution Control Board is executing a nationwide NAMP network comprising 326 monitoring stations covering 116 cities/towns in 28 States and 4 Union Territories of the country. The objectives of the NAMP are to determine status and trends of ambient air quality; to ascertain whether the prescribed ambient air quality standards are violated; to assess health hazard and damage to materials; to continue ongoing process of producing periodic evaluation of air pollution situation in urban and industrial areas of the country; to obtain the knowledge and understanding necessary for developing preventive and corrective measures; and to understand the natural cleansing process undergoing in the environment through pollution dilution, dispersion, wind based movement, dry deposition, precipitation and chemical transformation of pollutants generated.

Under the NAMP, four air-pollutants viz., Sulphur Dioxide (SO₂), Oxides of Nitrogen (NO_x), Suspended Particulate Matter (SPM) and Respirable Suspended Particulate Matter (RSPM or PM₁₀), have been identified for regular monitoring at all the locations. The monitoring of meteorological parameters such as wind speed and direction, relative humidity and temperature was also integrated with the monitoring of air quality. The monitoring of pollutants is carried out for 24 hours (4-hourly sampling for gaseous pollutants and 8-hourly sampling for particulate matter) with a frequency of twice a week, to have 104 observations in a year. The monitoring is being carried out with the help of Zonal offices of Central Pollution Control Board, State Pollution Control Boards/Committees, National Environmental Engineering Research Institute (NEERI) and other research institutions/universities. CPCB coordinates with these agencies to ensure the uniformity, consistency of air quality data and provides technical and financial support to them for operating the monitoring station. The survillance of NAMP stations is also undertaken through CPCB Zonal Offices in their respective Zones.

• Annual average concentrations of SO₂ were within the prescribed National Ambient Air Quality Standards (NAAQS) at almost all the locations.

• Decreasing trend has been observed in SO₂ levels in residential areas of cities like Delhi, Mumbai, Lucknow, Bhopal, Faridabad etc. during last few years. The decreasing trend in sulphur dioxide levels may be due to various pollution control measures undertaken such as reduction of sulphur in diesel etc. and use of LPG instead of coal as domestic fuel. Also, conversion of diesel vehicles to CNG may have contributed to reduction in ambient SO₂ levels.

• Annual average concentrations of NO₂ were within the prescribed National Ambient Air Quality Standards (NAAQS) at most of the locations.

• A decreasing trend has also been observed in NO₂ levels in residential areas of Madurai, Bhopal, Faridabad, Chennai etc. during last few years. Vehicles are one of the major sources of NO₂ in the country. The decreasing trend in nitrogen dioxide levels may be due to various measures undertaken for vehicular pollution control such as stricter vehicular emission norms etc. Trend in ambient NO₂ is fluctuating in many cities despite steep increase in number of vehicles.

• One of the major sources of high RSPM levels are vehicles. The vehicle are increasing exponentially in many cities. This is the single major factor for high RSPM levels.

• A decreasing trend has also been observed in RSPM levels in cities like Solapur, Lucknow, Bhopal, Hyderabad etc during last few years. Decreasing trend in RSPM levels may be due to various pollution control measures undertaken such as reduction of sulphur in diesel, stringent standard of particulate matter in diesel vehicles etc. Trend in ambient RSPM has been found fluctuating in many cities.

• Lower levels of RSPM were observed during monsoon months because of prevalent wet deposition. Higher levels of RSPM were observed during winter months because of prevaleat lower mixing heights and more calm conditions.

• Annual average concentrations of SPM exceeded the NAAQS in many cities.

• The sources of SPM include vehicles, natural dust, industries such as thermal power plants, sugar, cement etc., resuspension of dust, refuse burning etc. Trend in annual average concentration of SPM is fluctuating in many cities. Decreasing trend has been observed in cities like Ahmedabad. Decreasing trend in SPM levels may be due to various measures taken for vehicular and industrial pollution control. Vehicular pollution control measures include stringent vehicular emission norms, reduction of sulphur in diesel, stringent standard of particulate matter in diesel vehicles etc. Trend in ambient SPM has been found fluctuating in many cities.

The present National Air quality Monitoring Network is limited in its scope of application and hence, there is need to modernize the existing system to International standard. Internationally, use of Continuous Automatic Ambient Air Quality Monitoring is widely accepted. It is proposed to develop Automatic Air Quality Monitoring Network and a three level / data management & transfer system, initially involving 10 identified metro cities & cities where Continuous Ambient Air Quality Monitoring Station (CAAQMS) are already in operation. The proposed project was discussed in 51^st Conference of Chairman & Member Secretaries of Pollution Control Boards / Committees

Progress made on this project is given below:

Air Pollution is an emerging environmental issue in Asia as it is in other parts of the world. To cope up with the issue of transboundary air pollution in South Asia, the "Male’s Declaration on Control and Prevention of Air Pollution and its likely Transboundary Effects for South Asia" was adopted by the Ministry of the Environment & Forests at the seventh meeting of the Governing Council of South Asia Cooperative Environment Programme (SACEP), held on August 22, 1998 in Male, Republic of Maldives. The Male’s Declaration stated the need for the countries to carry forward or initiate studies and programme on air pollution in each country of South Asia. The Phase-I of the Male Declaration started in 1999 saw the establishment of the network of organizations to implement the Declaration and compilation of baseline information on air quality monitoring and management in the participating countries. Consequently a capacity building programme was initiated in Phase-II of the Implementation Programme 2001-2004, which included strengthening the monitoring network and training. Phase-III continuation of capacity building activities, impact assessment and information policy making is scheduled to be implemented during 2005-2008.

As part of the implementation of Male’ Declaration, the first monitoring station in India to study the transboundary effect of air pollutants has been established at Port Canning, Sunderbans. Monitoring for wet and dry deposition is being conducted at the station for the last one year. The annual Network Meeting of "Male’ Declaration on Control and Prevention of Air Pollution and its likely Tranboundary Effects for South Asia" was held in Delhi from October 11-13, 2005. The Network Meeting was inaugurated by the Hon’ble Minister of State for Environment & Forests, Shri Namo Narain Meena. The Network Meeting was followed by Regional Stakeholders’ Meeting on October 14 and Regional Coordination Meeting on October 15, 2005. Delegates from Nepal, Bangladesh, Sri Lanka, Iran Bhutan, Maldives, Pakistan and India participated in the mjeetings.

Central Pollution Control Board selected an ambient air quality monitoring station at Port Canning, West Bengal bordering Bangladesh for the study of transboundary movement of pollutants. CPCB Zonal Office Kolkata started monitoring at this station since September 15, 2004 for the air quality parameters like RSPM, NO₂ and SO₂ and monitoring of the adjacent water bodies like ponds and rivers, as well as sediment and soil. It was observed that from March 2005 till Sept 2005 concentration of RSPM in shift 1 (2PM-10PM) and shift 3 (6AM-2PM) were comparatively higher with respect to shift 2 (10PM- 6AM). Whereas concentration of RSPM in Shift 1 and 2 were comparatively higher than the Shift 3 between October 2004 -February 2005. Frequency of RSPM exceeding the permissible limit was almost nil during March to October and 42% to 92.8% during November to January with highest frequency in December. Concentration of SO₂ and NO₂ level were always far below the permissible limit. Concentrations of available nitrogen, phosphorous, organic carbon and exchangeable calcium and magnesium in the soil indicate that the soils are fairly fertile. The above parameters were also measured for sediment. The quality of sediment was found quite suitable for a balanced ecosystem. The quality of surface run-off pond water was found suitable for aquatic organisms including fish except marginal increase of chloride, sodium and sulphate indicating influence of seawater. The river water was found saline as reflected from the concentration of sodium, chloride, sulphate etc. clearly indicating the tidal influence.

The Central Pollution Control Board has been monitoring ambient air quality at seven locations in Delhi for the past many years. The locations have been categorized based on land use, i.e., residential, industrial and traffic intersection. The comparison of ambient air quality data during 2005 with previous years is shown below.

The air pollution in urban areas arise from a multitude of sources including natural as well as anthropogenic sources viz. industrial processes, automobiles, transport vehicles and domestic sources. The concentration of air pollution can vary considerably from one location to another as they depend not only on the quantities that are emitted but also on the ability of atmosphere to disperse the pollutants and on various physical and chemical dissipation processes liable to remove pollutants from the atmosphere. Because of this, the air pollution concentrations vary temporally, causing the air pollution pattern to change with different locations and time of the day, week or year. A study was carried out to study the pollution levels at different location in Delhi in addition to already operating fixed monitoring stations.

BSOF is being sporadically measured in RSPM at BSZ Marg Traffic Intersection Delhi since 2001. Benzene Soluble Organic Fraction (BSOF) mainly comprises of hundreds of particulate bound organic compounds present in ambient air. Some of the important BSOF compounds include Polycyclic Aromatic Hydrocarbons (PAHs), Dioxins and Furans, Oxidized Hydrocarbons (aldehydes, ketones, oxyacids etc.). Measurement of BSOF gives an idea about the anthropogenic emissions originating from the combustion of fossil fuels. The BSOF levels in RSPM at BSZ Marg in Delhi are presented below. The concentration of BSOF in PM₁₀ ranged between 16 – 70 µg/m³. Results indicate that BSOF during the winter months were higher ranging from 33 – 70 µg/m³, while the lowest values (16 µg/m³) were observed in monsoon period. The percent BSOF in PM₁₀ ranges between 4 and 25. The highest percentage was observed in July 2003 when average RSPM was found to be only 67 µg/m³ (perhaps due to wash out factor) but the BSOF even at such low levels of RSPM was found to be highest (25%) in comparison to other months.

Central Pollution Control Board is regularly monitoring BTEX (Benzene, Toluene, Ethyl-Benzene, and Xylene) in the ambient air at Sirifort using continuous BTEX – Analyzer (FID). Sirifort monitoring station is located in the premises of electricity sub station. The surrounding area is flat plateau with dense residential localities, commercial establishments and a famous sports complex. There is no major immediate source of air pollution in the vicinity of Sirifort monitoring station. However there may be some impact of vehicles plying on a busy road at a distance of approximate 100 meters from the station. The annual minimum, maximum and mean concentration of BTEX (Benzene, Toluene, Ethyl-Benzene, and Xylene) in ambient air at Sirifort in Delhi during 2005 is presented below.

The annual concentration was observed in the range of 3.0 µg/m³ to 17.9 µg/m³, 8.9 µg/m³ to 30.1 µg/m³, 1.8 µg/m³ to 13.5µg/m³ and 1.0 µg/m³ to 7.0 µg/m³ of Benzene, Toluene, Ethyl-Benzene, and Xylene (M&P-Xylene and O–Xylene), respectively. The annual mean concentration of Benzene, Toluene, Ethyl-Benzene and Xylene (M&P-Xylene and O–Xylene) were observed 9.1 µg/m³, 18.3 µg/m³, 5.6 µg/m^3, and 3.0 µg/m³ respectively.

Regular monitoring of SO₂, NO₂ and RSPM is being conducted round the clock on all working days in Kanpur at Vikas Nagar, which is considered as Residential area. The monitoring and analysis is done through IIT, Kanpur. Monthly average of RSPM and NO₂ for year April-December 2005 are shown in Figures below.

Central Pollution Control Board is operating Ambient Air quality monitoring station at West Zone office building at vadodara and monitoring parameters such as RSPM, SO2, Nox. The particulate matter in ambient air in Baroda is high due to heavy vehicular movement and the background dust. The RSPM mostly exceeded the prescribed limit. The NOx was also found more than the air quality standard limit on few occasions.

In compliance to the direction of the Hon’ble Supreme Court of India, CPCB has established monitoring stations to monitor SPM, RSPM, SO₂ and NO₂ at four selected locations at Agra viz. Tajmahal (a sensitive zone and one of the Seven Wonders of the World), Itmad-ud-daulah (historical monument surrounded by industrial and commercial area) and Rambagh, Nunhai (both are industrial zones located north to Tajmahal. The monitoring data indicated that SO₂ has been found maximum at Itmad-ud-daulah (19 µg/m³) during the month of July. The NO₂ and RSPM values were found maximum at Nunhai i.e. 48 µg/m³ and 460 µg/m³, respectively during the month of December whereas minimum at Tajmahal i.e.14 µg/m³ and 35 µg/m³, respectively during the month of August. The maximum SPM concentration (878 µg/m³) has been traced at Nunhai during the month of December and the minimum concentration (115 µg/m³) at Tajmahal during the month of September. All the parameters except SO₂ have depicted similar trend as observed during 2004 i.e. they attained their peak values in winter, which is attributed to less dispersion / lower mixing height in winter months.