Context

The smallest, invisible particles matter the most when it comes to dealing with air pollution, researchers have found in two recent studies, published in journals Faraday Discussion and Nature NPJ climate and atmospheric science.

About

Key-takeaways from the study

• Ultrafine particles — which have almost negligible weight and surface area and are hence are not considered a threat to the air we breathe — do have an effect on haze formation, visibility and air pollution.
• The smallest particles are formed from gaseous sulfuric acid and ammonia or amines, which are ubiquitous.
• The particles grow via condensation of organics and nitrate which are equally available throughout the city.
• The new particle formation and growth were equally important in contribution to haze formation as traffic and other anthropogenic activities.

A slow killer

• Atmospheric air pollution kills more than 10,000 people every day.

• Uttar Pradesh, Maharashtra, Bihar, West Bengal and Rajasthan account for over 50 per cent deaths attributed to air pollution in India, according to the same report.
• An old study in China claimed that Particulate Matter (PM) 1 contributed to 80 per cent of PM2.5. Evidence for health effects of PM1 is very limited, because it is not routinely monitored internationally.
• So far, the standards for PM1 have not been proposed by the World Health Organization or any other government agencies.
• While PM2.5 can reach lungs, PM1 can enter bloodstream.