smog
Vehicles drive through heavy smog in Delhi, India, November 8, 2017. Reuters

While cities like Delhi are facing acute air pollution due to smog, a NASA funded research has found that the ozone and the ozone-forming materials in the lower atmosphere are the major reasons for the pollution.

The NASA-funded research has found a way to use satellite measurements to identify precursor gases of ozone formation in the lower atmosphere, which has been recognized as a major reason for smog during the summers. This method could help the air quality managers to assess effective ways to reduce air pollution and improve the quality of air.

This research has great significance as the presence of ozone in the lower altitudes results in respiratory problems like asthma and bronchitis.

The ozone pollution near the surface of the earth was not detected earlier as the satellite measurements from the space would be misinterpreted due to the abundance of ozone in the upper levels of the atmosphere.

It was found that volatile organic compounds (VOC) and nitrogen oxides (NOx) reacts with the sunlight to generate ozone in the near-earth atmosphere.

The Dutch-Finnish Ozone Monitoring Instrument aboard NASA's Aura satellite helped in measuring the role of VOC formaldehyde and NOx in the Ozone formation.

According to the research paper published in the Journal of Geophysical Research: Atmospheres, Xiaomeng Jin at the Lamont-Doherty Earth Observatory at Columbia University in Palisades, New York said, "We're using satellite data to analyze the chemistry of ozone from space."

The researchers used computer models and space-based observations to study whether the ozone production has increased with the presence of NOx, VOCs, or with the mix of the duo in particular locations. The study was focused on ozone-polluted regions in North America, Europe, and East Asia during the summers when ozone formation would be at its highest rates due to triggered sunlight. The team found that the ozone formation would be lesser in regions with the lesser emission of the component molecule.

A 12-year data record of satellite observations on the New York City's ozone production found that ozone production during warm season was lesser in the presence of VOCs. Meanwhile, it was found that the ozone levels had reduced in 2015 when the city reduced its NOx emission. The researchers believe that reduction in the NOx emissions could help in further reduction of ozone production.

The Volatile Organic Compounds are formed naturally by several plants. They are also found in huge quantity in paint fumes, cleaning products, pesticides and as by-products of burning fossil fuels in factories and automobiles. Nitrogen oxides are found as a byproduct of burning fossil fuel in factories and automobiles and are abundant in urban regions.