Highway Research Record

Measurement of Vehicular Pollution at Selected Intersections in Delhi

Date of Start:October 2004
Central Road Research Institute, New Delhi

Present Status and Progress
The study was undertaken to understand the relationship between traffic flow and air pollution levels at the kerb sides with the distinct objectives to measurement the kerb-side air quality and study of traffic related attributes at selected intersections and one mid block section to account for the free flow conditions in Delhi and to find the existence of any meaningful relationship if any between vehicular traffic and observed air pollution levels.

Keeping the objectives of the study in mind, a total of four major intersections and one mid block were selected to conduct the classified traffic volume counts. The selected intersections in this study include Ashram intersection, R.K. Puram Sector-I crossing, Habitat Centre intersection and I.T.O. intersection which represent varying land uses and also one mid block road section representing free flow condition on N.H.2 (near C.R.R.I.) was selected. These locations have been chosen in consultation with the officials of SIAM. With the help of appropriately designed proformae and trained manpower, traffic volume counts have been conducted at each of the selected intersections for every 15 minutes during the period of the survey. Depending upon the volume of traffic, number of enumerators was allocated to count different types of vehicles independently for the same period. As this study is aimed at evaluating the existence of any meaningful relationship between vehicular traffic and observed air pollution levels, it was decided to classify the vehicles based on the fuel used (as in the case of cars, autos, taxis and buses) and engine capacity (as in the case of two wheelers).

With a view to make indicative assessment for the quality of air and its direct relation with traffic, hourly air pollution concentrations (of SO2, NOx, CO, HC, O3, PM and benzene) were measured along with the road traffic measurements for every 15 minutes during the survey period. The pollutant measurements were carried out using automatic pollutant-specific analysers.


The distribution pattern for a few of the pollutants was observed to corroborate well with the traffic flow characteristics. The observations are indicative of the fact that vehicular emissions were predominant contributors to the observed kerb side air quality. However, particulate matter (PM10) and other pollutants were not observed to be consistent with traffic, and might have been contributed from other sources as well. The transport of pollutants from other activity regions, under favourable meteorological conditions could not be ruled out as one of the influencing factors.


The study findings are based a limited data set in terms of number of sampling sites and number of observations.

The detailed study with greater spatial spread and number of observations may be helpful in drawing useful conclusions.


The Draft Report on the study was submitted in February 2005 to Society of Indian Automobile Manufacturers (SIAM).