| New Delhi |
October 17, 2020 4:40:52 am
Meteorological situations in Delhi have been “extraordinarily unfavourable” in September and thus far in October as in comparison with final yr, which has helped within the rise of air pollution ranges, Central Air pollution Management Board member secretary Prashant Gargava mentioned on Friday.Information shared by Gargava throughout a press briefing confirmed that the primary meteorological components that assist in dispersion of pollution have been weaker between September 1 and October 14 this yr as in comparison with the identical interval in 2019.
“Focus of PM2.5 and PM10 in October and September was a lot increased than the identical interval in 2019,” Gargava mentioned.The meteorological components that decide accumulation and dispersion of pollution embody the variety of wet days, air flow index, wind pace and mixing top. The overall quantity of rainfall within the interval between September 1 and October 14 was 121 mm final yr in seven wet days, whereas this yr it was simply 21 mm in three wet days.
Rain helps in settling down mud and different pollution suspended within the air. Air flow index — the sum of blending depth and wind pace, which is used to forecast the ambiance’s potential to disperse pollution — additionally remained low this yr.
A air flow index beneath 6,000 sqm/second with common wind pace lower than 10 kmph is taken into account unfavourable for dispersion of pollution. In September this yr, the common air flow index was 1,334 sqm/second as in comparison with 1,850 sqm/second final yr.
Between October 1 and 14, the common air flow index was 1,389 sqm/second as in comparison with 1,626 sqm/second final yr.
Mixing depth is the vertical top wherein pollution are suspended within the air. On chilly days with calm wind pace, this top reduces and leaves pollution suspended nearer to floor.
“If we’ve extra mixing top and extra winds, that’s good. If considered one of them reduces, then that creates an influence… In a landlocked space like Delhi, in winter, you have got completely no winds, and the blending depth additionally, which usually is way increased, upto 3,000 metres, will get lowered to 100-300 metres. So the (atmospheric) quantity wherein dispersion occurs will get suppressed. In winter, these two issues have an especially adversarial influence, ” Gargava mentioned.
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