The study will cover pollution from vehicles, construction work, industrial, housing and other activities. The cities to be studied are Bhopal, Indore, Ujjain, Dewas and Sagar. MPPCB officials said these five cities have been identified for carrying out the Sources Apportionment Study due to high pollution levels present there. The study will help identify reasons behind air pollution and arrive at a conclusion as to which source is causing how much pollution. Based on the findings, the authorities will try to cut down pollution levels.

However, the process will take time because experts point that at least three years are required for carrying out the study in one city. Besides, the cost of study is around Rs 1.5 crore per city.

Pollution is measured by taking into account level of sulphur dioxide (SO2), nitrogen oxide (Nox), RSPM10 and fine particulate matter (PM2.5) in the air. Cause of SO2 is vehicles. Nox is due to human activity, including vehicles and sewage among others. RSPM 10 is on account of dust, construction, including building of roads, while PM2.5 is as a result of dust, human activity and climatic conditions. Officials said that of the four, PM2.5 is most harmful for health since it goes inside human body and causes severe lung diseases.

PCB officials said respirable dust sampler instrument is used for measuring air pollution. Filter paper and cyclone are used for calculating PM10 (respirable particulate matter) and PM2.5, with the help of which dust particles are measured in the air, while absorbent solution helps measure if sulphur dioxide is present.

MPPCB chief chemist Shyamanuj Tiwari said the study, which is primarily based on measurements and tracking down the sources, will help in identifying the sources and the extent of their contribution. "In MP, it is being initiated by efforts of our member secretary AA Mishra. A workshop has been scheduled in the state capital on Thursday in which field experts will present case studies and their findings on ambient air quality in different cities," he said.

Officials said air pollution problem becomes complex due to multiplicity and complexity of the sources, which include industries, automobiles, domestic fuel burning, dust on road and construction.

A cost-effective approach for improving air quality in polluted areas involves identification of emission sources, assessment of extent of contribution of these sources on ambient environment, prioritising the sources that need to be tackled, evaluating various options for controlling the sources and formulation and implementation of action plans.

In MP, air quality is monitored at 37 places, including Ujjain, Bhopal, Indore, Dhar, Gwalior, Jabalpur, Sagar, Satna, Singrauli, Shahdol and Katni. Of these, Bhopal has the maximum six air quality monitoring stations.

Ambient air quality of Bhopal, Indore, Ujjain, Dewas and Sagar is moderate or close to moderate, which is just above poor category in ambient air quality index.