New Delhi: The Ministry of Science and Technology said aerosol particles smaller than 3nm which can grow to sizes with climate impact, have frequently formed in urban areas of India as scientists plotted The concentration, size and pattern of aerosol particles smaller than 3 nanometers at an urban location in India have found frequent formation of aerosol particles smaller than 3 nm in the atmosphere.
This is of critical importance because a major fraction of these newly formed particles can grow to the size of cloud condensation nuclei where they have climatic impacts.
The formation of small molecular clusters smaller than 3 nm in size is technically called aerosol nucleation, and the subsequent growth of these newly formed clusters to large sizes is called the formation of new atmospheric particles (NPF).
The formation of small molecular clusters smaller than 3 nm in size is technically called aerosol nucleation, and the subsequent growth of these newly formed clusters to large sizes is called the formation of new atmospheric particles (NPF). NPF is present everywhere in the Earth’s troposphere and is therefore an important source of many aerosols in the atmosphere.
Although it has been widely studied globally using field observations, laboratory experiments, and a modeling approach, it is largely unexplored in India.
Scientists at Hyderabad University have measured neutral particles smaller than 3 nm for the first time in an urban area in India. Dr Vijay Kanawade and Mathew Sebastian used the AIRMODUS nano condensation nucleus counter (nCNC) to measure the particle size distribution in the size range of 1 to 3 nm.
In the study supported by the Department of Science and Technology (DST) of the Climate Change Program Division, they made continuous observations since January 2019 at the campus site of Hyderabad University and reported the rate of formation of small molecular clusters in a regime smaller than 3 nm. , where the nucleation of aerosols is triggered.
This work was recently published in the journal Atmospheric Environment.
Research has shown that a pool of particles smaller than 3 nm is often present in the atmosphere, but the rate of growth of these clusters depends on various factors. Scientists observed that only half of these events showed newly formed molecular clusters exceeding the size of 10 nm. Thus, the particle size distributions show conventional banana-shaped aerosol growth, indicating a regional MFN event.
The team found a strong positive correlation between concentrations of particles smaller than 3 nm and concentrations of sulfuric acid, confirming the potential role of sulfuric acid in the formation of particles smaller than 3 nm. While NPF often begins with sulfuric acid in the atmosphere, sulfuric acid alone fails to explain the observed particle formation and growth rates in the atmosphere. Other vapors such as ammonia, amines and organics play a crucial role in the growth of the newly formed particles.
Additionally, these newly formed particles did not always reach large sizes, and the team hypothesized that particle growth was limited by lower concentrations of condensable vapors such as organic compounds. He called for research using advanced instrumentation to understand the mechanisms behind MFN in various environments across India.