Pollution: particulate matter in India higher than WHO limit

Updated - November 16, 2021 04:45 pm IST

Published - May 07, 2015 02:27 am IST

In 2010, air pollution killed nearly 600,000 people in India, according to the World Health Organisation (WHO). The situation has not changed in the last five years. A recent study shows that a significant population of Indian subcontinent breathes air with much higher particulate matter that is lesser than 2.5 micrometre (PM2.5) in size than the limit set by the WHO. Outdoor air pollution as a whole, especially the particulate matter, has been declared as class-1 cancer-causing agent (carcinogen) in 2013 by the International Agency for Research on Cancer (IARC), which is part of the WHO. Besides, it causes other respiratory and heart diseases.

The PM2.5 is particularly dangerous and can cause adverse health effects owing to its greater penetrability into the human respiratory system and eventual accumulation in human organs and blood. Rural women, children and elderly population are more prone to diseases caused by air pollution. Rural women, in particular, face a greater risk from indoor pollution — locally made mud stoves fuelled by solid biofuel emit a far greater amount of finer particulate matter.

Air quality of any area depends on local emissions, long-range transport, local and regional weather patterns, and to some extent the topography of the region. Due to increased buoyancy and efficient ventilation in summer, pollution plumes rise effortlessly to the free atmosphere. This leads to a reduced level of surface level PM2.5 concentration in our breathing zone. The problem gets aggravated during winter. Adverse conditions during winter help trapping of pollution leading to elevated level of surface PM concentration.

Compared with peninsular India and coastal regions, the situation is far worse in the Gangetic Basin, especially during winter months. The Himalayas act as a barrier to dissipation of pollution plumes emanating from the cities located in the Basin. As a result, cities in the Basin are more prone to sustained bad air quality.

Evidence is emerging that shows a strong positive relationship between increased pollution levels and occurrence of dense fog episodes. This clearly demands far more stringent emission norms in the cities located in GB if we have to achieve air quality to prescribed National Index. Although water is acknowledged as a precious resource, the air that we breathe is still not given a similar importance. It is time that an Air Resource Board be created, to begin with in a specific affected region of the country, which is equipped with larger and well-trained staff, technologists and legal aids, and has advanced monitoring stations — stationary and mobile — under it.

The state of California was infamous for its worst air quality in the U.S. in early 1950s due to large emissions and valley-like topography that allows trapping of pollution. However, with science-based policies, appropriate technologies and strict regulations, residents of California enjoy better air quality today despite a steady growth in transportation sector and continued industrialisation.

The State made effective use of diesel particulate filter (DPF) that does not allow emission of PM2.5 into environment in vehicular exhaust system. Refineries were augmented to produce low-sulphur fuel, a necessity for DRF installation. Recent epidemiological studies show reduced mortality and hospital admittance due to air pollution. The level of soot (therefore PM2.5) in California has reduced drastically over the last three decades, as a recent study reveals.

India has begun taking steps in the right direction. The National Air Quality index, introduced recently, has created greater awareness of air pollution amongst the people. Recently, plying of diesel vehicles older than 10 years has also been prohibited.

But the situation demands more action in order to restore good air quality and clear visibility. The economic gain due to avoidable loss of human life is too huge to be ignored. Technical intervention through efficient cooking stoves can significantly improve the lives of rural women. Improved power situation, especially in cold days, together with better handling of municipal waste and trash, can also help in achieving better air quality in the cities. Securing clean air, without compromising development, is achievable and sustainable. Environment protection is a challenge that has to be addressed more comprehensively.

Central Pollution Control Board can be divested into various regional air boards that will be responsible for securing the environment in a more proactive manner. If mandatory, more laws need to be enacted and strictly enforced to accomplish these goals.

( S.N. Tripathi is aProfessor at Centre for Environmental Science Engineering, IIT Kanpur)

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