Plastic waste in our oceans is now a well-known problem, but new data shows that plastic also contributes to air pollution in Indian cities.
For several years, scientists were puzzled as to why Delhi was more prone to thick smogs than other polluted cities like Beijing. New research links this to tiny particles of chloride in the air that contribute to the formation of water droplets. Globally, chloride particles are mostly found near the coast due to sea spray, but the air in Delhi and inland India contains much more than expected.
Initially, the sources were believed to be illegal factory units in the Delhi area that recycle electronics and those that use strong hydrochloric acid to clean and process metals. These are certainly part of the problem, but new measurements have revealed a different source.
The researchers examined the other pollutants, which increased simultaneously with the chloride particles. This chemical fingerprint matched the incineration of household waste containing plastic and the incineration of plastics themselves. It is estimated that these large amounts of chloride are responsible for about half of the smog incidents in Delhi.
In low-income countries, around 90% of waste ends up in open landfills or is incinerated in the open air. If you set plastic on fire, it quickly reveals its origins as an oil-based product by producing copious amounts of black smoke. Using data on garbage levels from around the world, researchers at London’s King’s and Imperial Colleges have estimated that soot from open waste incineration has global warming that is between 2% and 10% of global carbon dioxide emissions.
Burning plastics also produces large amounts of dioxins and other highly toxic pollutants that can remain in the food chain. Modern waste incineration plants in the UK and Europe are making great efforts to reduce these toxic emissions. However, there is no protection if waste is incinerated at home or outdoors.
The waste incineration problems in Indian cities don’t end there. As James Allan of the University of Manchester, who participated in the latest Indian study, said the extra chloride could encourage chemical reactions between different air pollutants. This includes the addition of ground level ozone across India. It is already estimated that this will reduce the yields of some Indian crops by 20% to 30%.
Better waste management must be a priority, but removing plastic pollution also requires rethinking the way plastics are produced and used around the world.