Sharad Gokhale, professor of environmental engineering at the Indian Institute of Technology, Guwahati, specialises in the study of urban air pollution and environmental noise. He spoke to HT about the role of citizens and the state in reducing air pollution levels.
What can people do to protect themselves from air pollution involving dust from construction sites and pavements of roads?
We need source-wise mitigation of different sources of pollutants in Mumbai. A construction site should be enclosed with a cloth or metal screen to prevent dust generated from blowing out of the site. During the clearing of the site, water should be sprinkled to reduce dust.
Sidewalks are usually not paved or tiled, and become another important source of dust, which is re-suspended when a vehicle passes. Open burning of tyres and other solid waste should be banned. People need to use bus transport whenever possible and adopt car-pooling. Authorities have to make public transport adequate, comfortable and accessible. To encourage walkers and cyclists, sidewalks need to be safer.
Large quantities of pollutants are generated from vehicular emissions due to traffic congestion and crowded parking spaces. What can be done to reduce this problem?
An effective traffic flow management plan can reduce urban air pollution by 15-20%, as traffic speed, frequent start-stop often contribute to more emissions. It is necessary to make traffic flow smooth by minimising interruptions.
There is no check on the adulteration of fuel. Cleaner technologies have advanced and less polluting fuels are being sought by policy makers, but fuel adulteration too is bad for air quality. Multi-layer parking spaces near urban centres and banning entry of cars in main urban centres would be the best option. People should also obey speed limits, use cruise control, turn off engines at traffic lights, junctions.
What are the primary causes of indoor air pollution at workplaces or residential areas, and their remedies?
We spend most of our time indoors. According to the global burden of disease report, indoor air pollution is ranked the third major cause of deaths. There are sources of pollutants indoors such as paints, used furniture, house-cleaning detergents, cooking and smoking.
Certain lifestyle related practices are taking a toll on our health. Nowadays, houses are painted with sprayers instead of brushes, with particles from paints becoming airborne. In offices, replacing old equipment with new ones can reduce ozone levels.
Planting trees on both sides of the road arrests pollution significantly. A specific crown size and height in trees can manipulate the dispersion of air pollutants within traffic corridors, to help reduce exposure to air pollutants.
Can you give us an example of a city that has adopted unique measures to save citizens from bad air quality?
There is no city where a specific action has changed the pollution scenario drastically. A few cities in the world are regarded as clean and better despite being populated and industrialised, such as Honolulu in the USA or Calgary in Canada, or Singapore. They have adopted use of public transport, well-planned infrastructure, enforcement against smoky vehicles, tightening of air quality standards, over the years. They have also adopted serious mass awareness programmes about the causes of air pollution and its effect on our children and elderly people.
What according to you is lacking in the endeavours of state government bodies that calculate RSPM, NOx and SO2?
These bodies need to take greater responsibility than mere monitoring of air pollutants and uploading information on websites. A special cell needs to be introduced for dealing with vehicular pollution in urban centres. They can identify the attainment and non-attainment areas, hotspots, and issue a public warning of harmful effects of air pollution and what people should do.
Technological solutions may take a while, but by involving people, the state pollution control board can address this issue. Collective effort can work wonders.