Sion, which marks the northern end of the island city of Mumbai, has topped the list of ‘hazardous air’ sites in Maharashtra. According to the findings of an assessment study of ‘ambient air quality’ in the state, carried out by National Environmental Engineering Research Institute (NEERI), Sion had ‘hazardous air’ for 21 per cent and ‘very unhealthy air’ for 26 per cent of the time between 2008 and 2011. The report, which was recently submitted to the Maharashtra Pollution Control Board (MPCB), includes the statistical analysis of ambient air quality data collected from 73 monitoring stations across 17 districts in Maharashtra from 2008 to 2011.
MPCB officials said the quality of air continues to be unhealthy even after 2011. “From 2011-2013, the air quality recorded at Sion is alarming. This is mainly due to construction practices in major infrastructure projects and vehicular pollution. This area does not have industries but is still very polluted,” said V M Motghare, joint director, air pollution control. MPCB is likely to come out with a similar report on air quality data, collected between 2011 to 2014, in June.
The study found that the overall air quality index of Mumbai is pointing towards ‘unhealthy’ to ‘unhealthy for sensitive group’ from the data from 2008 to 2011. The air quality was monitored at Sion, Bandra and Mulund by the MPCB and at Kalbadevi, Worli and Parel by NEERI. The report stated that hotspots such as Sion, Bandra and Mulund required urgent attention.
The ambient air pollution was assessed by calculating the Air Quality Index (AQI), which is a standardised indicator to determine the quality of air and associated health effects. While AQI range of 0-50 indicates ‘good’, an AQI of more than 300 for Respirable Suspended Particulate Matter (RSPM) and more than 241 for oxides of sulphur (SO2) and nitrogen (NO2) indicates ‘hazardous’.
According to the report, at Sion, in 2008, 2009 and 2010, the air quality was ‘hazardous’ to ‘very unhealthy’ except from June to August, when it was ‘unhealthy for sensitive group’ or ‘moderate’.
In 2011, the air quality was ‘very unhealthy’ in late winter and ‘unhealthy for sensitive group’ during the monsoon. During this period, while the maximum concentration of RSPM showed 90-100 per cent annual exceedance over acceptable standards, NO2 concentration showed 99 per cent exceedance.
“Prolonged exposure to vehicular pollution causes bronchitis-like symptoms. What starts with a cough and eye irritation could lead to chronic bronchitis and obstructive pulmonary diseases in the long run,”said Dr Amita Athavale, professor and head of environmental pollution research centre at KEM Hospital.
The report, however, pointed out that many air quality monitoring stations in the state had poor quality control. “MPCB informed us that the monitoring station at Sion is right in front of the highway and Sion hospital behind it acted as an obstruction. This does not allow for dispersion of polluted air, which is essential for proper monitoring of ambient air quality,” said Indrani Gupta, senior principal scientist at NEERI, who headed the study.
MPCB claims that it has started work on improving the quality of monitoring stations in the state. “We need to find a site that is free from obstruction and is secure, like a government building. Finding a place that fits these criteria is difficult in Mumbai,” said Motghare, adding that MPCB was trying to increase the number of monitoring stations in the state.