Govt.
of India

Central Pollution Control Board

IT Division

Government of India · dated 30.04.2015

Technical Summary Page

Protocol for Data Transmission from CAAQM Stations (CPCB)

All Continuous Ambient Air Quality Monitoring stations in India, including those operated by CPCB, State Pollution Control Boards, DPCC, IMD, and industries, transmit 15-minute average pollutant data to CPCB’s central portal. This protocol standardizes the data file format, parameter names, units, and connectivity requirements so that data from every station remain consistent and can be reliably ingested by the national system.

Protocol Intent

Uniform station file naming and record structure.

Consistent pollutant abbreviations, units, and conversions.

Reliable transmission to CPCB central infrastructure.

Support for lost-data back-filling and operational audits.

Data File Format Requirements

Stations generate a real-time data file containing 15-minute average values and update it every 15 minutes at fixed intervals such as 00:15, 00:30, 00:45, and 01:00.

The file name must exactly match the station display name, with no spaces or special characters, for example Sanathnagar or NehruNagar.

The file is stored locally, such as in c:\data\, and records are appended sequentially.

Each file should contain a maximum of 97 lines and must be maintained on a First-In-First-Out basis.

Duplicate entries are not permitted.

The station system must be able to regenerate a previous day’s file on request so that lost data can be back-filled in the CPCB central database.

Standard Parameter Names, Units & Conversion Factors

Code	Parameter	Unit	Conversion / Note
Temp	Rack temperature	°C	—
CO	Carbon monoxide	mg/m³	1 ppm CO = 1.145 mg/m³
SO2	Sulfur dioxide	µg/m³	1 ppb SO2 = 2.62 µg/m³
NO	Nitric oxide	µg/m³	As approved by analyzer output convention
NO2	Nitrogen dioxide	µg/m³	1 ppb NO2 = 1.88 µg/m³
NOx	Oxides of nitrogen	µg/m³	Derived / analyzer standard
Ozone	Ozone	µg/m³	1 ppb O3 = 1.96 µg/m³
PM10	Particulate matter ≤10µm	µg/m³	—
PM2.5	Particulate matter ≤2.5µm	µg/m³	—
Benzene	Benzene	µg/m³	1 ppb Benzene = 3.19 µg/m³
Toluene	Toluene	µg/m³	Analyzer / approved factor
Xylene	Xylene	µg/m³	Analyzer / approved factor
Ethyl Benzene	Ethyl benzene	µg/m³	Analyzer / approved factor
MP-Xylene	Meta / para xylene	µg/m³	Analyzer / approved factor
CH4	Methane	µg/m³	Analyzer / approved factor
NH3	Ammonia	µg/m³	1 ppb NH3 = 0.70 µg/m³
HCHO	Formaldehyde	µg/m³	Analyzer / approved factor
Hg	Mercury	µg/m³	Analyzer / approved factor
WS	Wind speed	m/s	—
WD	Wind direction	deg	—
AT	Ambient temperature	°C	—
RH	Relative humidity	%	—
BP	Barometric pressure	mmHg	—
SR	Solar radiation	W/m²	—
RF	Rainfall	mm	—
VWS	Vertical wind speed	station-defined	—

Note: Any additional parameter requires prior approval of the CPCB IT Division.

Internet Connectivity Requirements

24×7 connectivity is expected with 99.9% uptime.

Each station should maintain two live-ready connections: a leased line of at least 1 Mbps and a broadband connection over a telephone line.

Auto-failover between the two connections should be enabled wherever feasible.

Datacard connectivity is not acceptable except in special circumstances and only after consultation with the CPCB IT Division.

Connectivity Model

Primary: Leased line (minimum 1 Mbps)

↓

Secondary: Broadband over telephone line

↓

Auto-failover preferred for continuity

Station Information to be Submitted

Area map showing the station location

Latitude, longitude, and altitude

Photographs of the station and nearby areas

A one-page write-up on nearby activities and pollution sources such as roads, railways, restaurants, and generator sets

Station Context Submission

CPCB requires both spatial context and field-level station documentation so that the monitoring site can be interpreted correctly in relation to nearby activities, local sources, and infrastructure conditions.

Data File Record Format (Annexure I)

Each record is a comma-separated line with eight fields: Station name, Parameter, Date from, Date to, Value, Calibration flag, Maintenance flag, and Remark.

8-Field Layout

1. Station name

2. Parameter

3. Date from

4. Date to

5. Value

6. Calibration flag

7. Maintenance flag

8. Remark

Sample Records

Sanathnagar,CO,27-04-2015 13:00,27-04-2015 13:15,0.2497,0,0,analyserfaulty

NehruNagar,PM10,27-04-2015 13:15,27-04-2015 13:30,118.0000,0,1,maintenancemode

Flag definition: 0 = normal operation; 1 = calibration or maintenance mode ON. Readings captured with active calibration or maintenance flags are excluded from averaging.

Official Protocol Document

Source: Central Pollution Control Board (CPCB), IT Division, Government of India — dated 30.04.2015.

Download Official Protocol (PDF)

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