Air report: less noise,more colour

THERE was good news on the noise front this Diwali on Saturday,but the bad news was the increase in use of coloured fireworks,which left its aftereffects on air.

According to experts,there was a significant rise in gaseous pollutants. An analysis of air and noise quality shows an overall decline in suspended matter and haze — a direct result of decrease in noise level on Saturday — but an increase in gaseous pollutants like nitrogen oxides and sulphur. This indicates a high number of colour crackers and fireworks were used,experts said.

Delhiites in most areas also seem to have bypassed the norms: the loudest period in the Capital on Friday night was between 9 and midnight,says a Delhi Pollution Control Committee (DPCC) official. Noisy crackers are banned after 10 pm.

As an indicator of the increase in colour fireworks,data collected by the Central Pollution Control Board (CPCB) shows the level of sulphur dioxide in air almost doubled when compared to last Diwali’s data. As per CPCB,the range of sulphur dioxide was between 8 mg and 42 mg per metre cube (or m3) this year — it was found at 7 mg to 24 mg/m3 last year.

Nitrogen oxide levels increased at 22 locations across the city,according to data collated.

While less than last year,a comparison of data collected by the Delhi Pollution Control Committee and CPCB spanning 49 locations show that level of Respirable Suspended Particulate Matter (RSPM) exceeded limits at most locations. While the safe limit for RSPM is 150 mg/m3,it between 316 mg and 466 mg/m3 this year,the CPCB says.

Last year,the levels were between 550mg and 930 mg/m3.

RSPMs are very small particles,less than 2.5 microns in size and dangerous to health.

Pahar Ganj was found the most polluted area on almost every count.

Data accessed by Newsline for Sunday showed haze and pollution present in air the day after Diwali: at ITO,in Central Delhi,the RSPM levels were found at 314 mg/m3 — against prescribed limits of 150 mg/m3. A DPCC official said,“This year,people appear to have burst crackers with more colour,perhaps to evade the noise barrier and also due to increased awareness. But these fireworks and crackers contain metallic oxides,which lead to a general increase in gaseous pollutants.”

Crackers with more light and spark also contain sulphur — thus the increase in sulphur dioxide levels.

Noise levels fell marginally this Diwali: CPCB registered average noise levels of 82 decibels,compared to 85 decibels last year. DPCC registered a greater range of noise,though still less clamourous than last year: between 71 to 78.9 decibels,compared to 67 to 79.5 decibels last year.