Delhi air heavy with PM1 pollutant

The level of particulate matter measuring less than one micron (PM1) — ultrafine particles that can reach your bloodstream when inhaled — has been shooting up at least five times than what it usually remains on a day when air quality in Delhi is satisfactory or moderate.

India’s most advanced air quality monitoring station, which was installed at the Town Hall in Old Delhi’s Chandni Chowk area in July, has thrown up this data. The station was set up by SAFAR, which comes under the Union ministry of earth sciences and is India’s official pollution forecasting system.

“The level of PM1 was recorded to be the lowest on July 27. It was just 10.02ug/m3. But on July 2, the level of PM1 had shot up to be 65.43ug/m3. Unlike other particulate matters, such as PM2.5 and PM10, the world is yet to come up with safe limits or permissible standards for PM1. Hence, it can’t be said how much above safe limits the level of PM1 had shot up,” said Gufran Beig, who heads SAFAR.

But to simplify things, experts said that the level of PM1 on July 27 (10ug/m3) could be considered as ‘safe’ because Delhi’s Air Quality Index was very close to ‘Good’ on that day. The AQI on July 27 was 50, which was in the ‘satisfactory’ range and just five notches above ‘Good’ quality air.

The levels of PM2.5 and PM10 were both within their permissible limits of 60ug/m3 and 100ug/ m3 on that day.

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