The Air Quality Index (AQI) at nine real-time air quality monitoring stations managed by the Kerala State Pollution Control Board has worsened after the relaxations came into force post lockdown.
The AQI levels had witnessed a considerable reduction, from the ‘moderate’ range (100) to the 'good' category (50), during the lockdown period. The average air quality index of most of the stations was around 50 (good) from March to October last year, except for Vytilla, M.G. Road in Ernakulam and Kollam where it touched 100 in September, according to an assessment by the board. The AQI of all stations went up to 100 (moderate) while some stations crossed 100 (unhealthy for sensitive groups) between October and December. The study found that the air quality in stations such as Vyttila, Thrissur and Kollam often crossed 150 (unhealthy) and rarely went up to 200 (very unhealthy) after further relaxations.
The nine real-time air quality monitoring stations are located at Plamoodu and Karyavattom (Thiruvananthapuram), Polayathodu (Kollam), MG Road, Vyttila, and Eloor (Ernakulam), Thrissur (Corporation limits), Palayam (Kozhikode), and Thavakkara (Kannur). The average AQI was calculated over a period from January 1 to December 31.
Within range
The AQI, which used to spike between March and May every year owing to lack of rain, remained in the good to moderate range in view of the lockdown in all stations. The reduction in overall traffic resulted in clear skies and clean air. However, the revival of the economic activity and increase in movement of trucks and other commercial vehicles in the post-lockdown phase led to an increase in air pollution.
The monitoring station at Polayathodu recorded the highest value of 278 in the maximum AQI level while the corresponding figures in Vyttila and Thavakkara were 235 and 228 respectively. The levels between 200 and 300 are considered ‘very unhealthy’ as per the standards prescribed by the Central Pollution Control Board under its National Air Monitoring Programme. The maximum AQI levels in other stations were Plamoodu 174, Thrissur 165, Eloor 152, M.G. Road 144, Karyavattom 125, and Palayam 123.
