Abstract
The world is currently going through the COVID-19 pandemic which has caused hundreds of thousands of deaths in just a few months. Considering the need for lockdown measures, most countries, including Malaysia, have implemented ‘Movement Control Orders’ (MCOs) as a prevention step to reduce the deadly spread of this disease. Local and worldwide media have reported the immediate improvement of air quality due to this event. Nevertheless, data on the effects of MCOs on air quality at local scales are still sparse. Here, we investigate changes in air quality during the MCO at an urban area using the air sensor network AiRBOXSense which measures monoxide (CO) and particulate matter (PM2.5 and PM10). In this study, air pollutant data during normal days were compared with MCO days using a reference analyser and AiRBOXSense. The results showed that the levels of the measured pollutants dropped by ~20 to 60% during the MCO days at most locations. However, CO in Kota Damansara (KD) dropped to 48.7%, but PM2.5 and PM10 increased up to 60% and 9.7% respectively during MCO days. Local burning activities in the residential area of KD are believed to be the main cause of the increased PM levels. This study has proven that air pollutant levels have significantly fallen due to the MCO. This air quality level information showed that the reduction of air pollutants can be achieved if traffic and industry emissions are strictly controlled.
Highlights
The World Health Organization (WHO) declared the COVID-19 outbreak as a pandemic on 11th March 2020 (WHO, 2016, 2020)
The daily average concentrations for carbon monoxide (CO), PM2.5 and PM10 in the Petaling Jaya City (PJ) area measured by AiRBOXSense were 0.54 ± 0.14 ppm, 19.1 ± 9.75 μg m–3 and 35.5 ± 17.6 μg m–3, respectively
The concentrations of CO, PM2.5 and PM10 were observed by AiRBOXSense sensors and continuous air quality monitoring system (CAQMS) over the Klang Valley region
Summary
The World Health Organization (WHO) declared the COVID-19 outbreak as a pandemic on 11th March 2020 (WHO, 2016, 2020). In many countries, including Malaysia, a pandemic action plan has been announced by authorities. One of the action plans is known as a Movement Control Order in Malaysia (MCO) to stop the spread of COVID-19 while transmission and mitigation can be further understood (Hadei et al, 2020; Hsiao et al, 2020). There are fewer vehicles on the roads, many cancelled flights and restricted construction and industrial activities which has led to plummeting levels of air pollutants. There has been an ancillary health benefit of reducing air pollution due to the MCO
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