Air Quality Unit

NBROs’ contribution to the National Air Quality Management has a long standing history as a pioneer air quality monitoring agency.

In all national committees and dialogues which were conducted to address the air pollution management in the country recognizes the Air Quality Unit of the ESSD as a leading mandated air quality monitoring facility. The unit has been disseminating ambient air quality status data to these committees for decision making apart from serving as technical experts in these committees. Further the unit which holds the largest air quality database in the country is shared with the scientific community at national and international workshops and conferences such as annual Air Resource Management Workshop and South Asia Better Air Quality Management Conference.

Currently the air quality monitoring unit includes staff and instrumentation of both field and laboratory monitoring. The unit has also developed a unique low cost monitoring facilities through extensive research to monitor SO2 and NOx in the ambient air by passive wet chemical monitoring techniques.

aqcoordinatorMr. H.D.S. Premasiri
Coordinator / Senior Scientist Air Quality Studies

+94 112 588 946 Ext: 600
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Road Development Projects

  • Southern Expressway Extension (Mathara to Betiatta) - China National Aero Technology International Engineering Corporation
  • Southern Expressway Extension (Mattala To Hambantota Via Andarawewa) - China Harbour Engineering Company Ltd
  • Southern Expressway Extension (Beliatta To Wetiya)- China State Construction Engineering Cooperation LTD
  • Vavuniya-Horowpathana (A 029) - Access Engineering PLC
  • Vauniya- Horowupathana - Edward and Christie (Pvt) Ltd.
  • Kerawalapitiya to Kadawatha - Outer Circular Highway (Phase III) Project

Baseline Survey for EIA Studies

  • Ruwanpura Expressway - Skill International (Pvt) Ltd.
  • Waste to Energy Project - Mahara - EML (Pvt) Ltd.
  • CRISH Tower project - Colombo - EML (Pvt) Ltd.

Construction Projects

  • Kandy City Waste Water Management Project (KCWMP) - JFE Engineering Corporation
  • Waterfront Integrated Resort Project (HKN Joint Venture)-Hyundai Engineering & Construction Co., Ltd.
  • Vauniya Water Project - Sierra Construction
  • Colombo Waste Water Project - R N Construction
  • Colombo Waste Water Project - L & T Construction

Industrial AQ consultancies

  • Camso Loadstar (Pvt) Ltd.
  • Diesel & Motor Engineering PLC
  • Ceylon Petroleum Corporation – Refinery
  • Hanwella Rubber Products Ltd, Pahathgama, Hanwella
  • Asiri Hospital Ltd.
  • Merbok MDF Lanka (Pvt) Ltd - Horana

Ambient Air Quality

  • Nitrogen dioxide (NO2)
  • Sulfur dioxide (SO2)
  • Suspended particulate matter (SPM)
  • Particulate matter (PM 10 & PM 2.5)
  • Carbon monoxide (CO)
  • Carbon dioxides (CO2)
  • Ozone (O3)
  • Lead (Pb)
  • Volatile Organic Compound(VOC)

Indoor Air Quality

  • Total Volatile Organic Compounds (TVOC)
  • Carbonic Acid (H2CO)
  • RH & T
  • Nitrogen dioxide (NO2)
  • Sulfur dioxide (SO2)
  • Particulate Matter (PM 10)
  • Carbon monoxide (CO)
  • Ozone (O3)

Stack Emissions (flue gas analysis)

  • Sulfur dioxide (SO2)
  • Nitrogen dioxides (NOx)
  • Carbon monoxide (CO)
  • Carbon dioxides (CO2)
  • Temperature
  • Heavy Metals
  • Total Suspended Particulate Matter (TSPM)
  • Oxygen(O2)


  • Day Time
  • Night Time


  • Cl
  • Acid mist
  • NH3

Lighting Levels
RH & T

RMV Project

Monitoring of Ambient Air Quality in Main Urban Cities in Sri Lanka was started in the year 2012 by NBRO from the VET Trust Fund given by the VET Project of RMV and the project was continued in the 2016 as well.

The project is a nationally important project and the NBRO acts as the monitoring agency for Vehicular Emission Control Program, implemented by the government under “Clean Air 2012” program of which the main focus is to improve air quality by controlling vehicular emissions. Under this project, ambient air quality is monitored at Colombo, Gampaha, Horana, Kaluthara, Rathnapura, Kandy, Kurunegala and Anuradhapura areas.

The project involves collection of substantial amount of data in the field as well as in the laboratory, analysis of results using descriptive statistics and testing for statistical significance, preparation of reports of high quality including photographs, maps and graphical interpretations etc., and presenting outcomes at the official forums of VET steering committee and in national air quality forums.

The monitoring methodology uses passive sampling technology which includes a device developed by scientists in Air Quality Studies Unit of NBRO, which captures pollutants in the ambient air and analysis in the laboratory using standard wet analyses methods; NO2 – Saltzman’s method (Colorimetry) and SO2 - Ion Chromatography (IC) method.

The monitoring program covers urban cities in 10 districts of the country and collections of samples on monthly basis amounting to a total of 4312 samples.

Passive Air Sampling

Passive air Sampling Device

Urban Area No of Locations Urban Area No of Locations
Colombo 19 Rathnapura 8
Gampaha 11 Kandy 13
Horana 5 Kurunegala 6
Kaluthara 5 Anuradhapura 5
Galle 6 Badulla Started in July,2016

According to the monthly spatial variation of SO2 and NO2 levels from January to May of 2016, no significant variation of exposure levels can be seen. However, the locations which have indicated highest exposure levels in past years represent the highest levels in this year as well. Also the highest values are observed in high traffic congested areas compared to other surrounding areas. Accordingly, highest exposure levels are recorded in Colombo, Gampaha, Kandy & Galle urban areas compared to other areas. Average levels of SO2 and NO2 in each location are within the 24 hour average of National Ambient Air Quality standard levels. However, the average NO2 exposure levels in Colombo, Gampaha, Galle and Kandy areas exceeded the annual WHO Guideline levels and the average SO2 exposure levels of almost all areas exceeded the 24 hour WHO Guideline levels.

Boxplot of SO2 Concentration in each urban area during the year 2016

Boxplot of NO2 Concentration in each urban area during the year 2016

Mr. HDS Premasiri, Coordinator of Air Quality Studies Unit is the lead scientist in this project and is solely responsible for execution of the project tasks within the time schedule, to produce deliverables with high quality meeting the required norms and participate in the technical forums.

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