The World Health Organisation (WHO) in its first ever update since 2005, has tightened global air pollution standards in recognition of the emerging sience in the past decade that the impact of air pollution on health is much more serious than earlier envisaged.
The move doesn’t have an immediate effect in India as the National Ambient Air Quality Standards (NAAQS) do not meet the WHO’s existing standards. The Government has a dedicated National Clean Air Programme that aims for a 20% to 30% reduction in particulate matter concentrations by 2024 in 122 cities, keeping 2017 as the base year for the comparison of concentration. However, experts say the WHO move sets the stage for eventual shifts in policy in the government towards evolving newer stricter standards.
The upper limit o annual PM2.5 as per the 2005 standards, which is what countries now follow, is 10 micro-gram per cubic metre. That has now been revised to five micro-gram per cubic metre. The 24-hour ceiling used to be 25 micro-gram but has now dropped to 15. The upper limit of PM10, or particulate matter of size exceeding 10 micro-gram, is 20 micro-gram and has now been revised to 15, whereas the 24-hour value has been revised from 50 to 45 micro-gram. India’s NAAQs- last year revised in 2009- specify an annual limit of 60 micro-gram per cubic metre for PM10 and 100 for a 24-hour period.
|PM2.5 annual mean||10||5||40|
|PM2.5 24-hour mean||25||15||60|
|PM10 annual mean||20||15||60|
|PM10 24-hour mean||50||45||100|
“WHO’s new Air Quality Guidelines are an evidence based and practical tool for improving the quality of the air on which all life depends. I urge all countries and all those fighting to protect our environment to put them to reduce suffering and save lives,” WHO Director General Tedros Adhanom Ghebreyesus said in a statement.
Every year, exposure to air pollution is estimated to cause 7 million premature deaths and result in loss of millions more healthy years of life.