Special Issue on “COVID-19 Aerosol Drivers, Impacts and Mitigation” (II)

Mohd Shahrul Mohd Nadzir This email address is being protected from spambots. You need JavaScript enabled to view it.1, Maggie Chel Gee Ooi2, Kemal Maulana Alhasa3, Mohd Aftar Abu Bakar5, Anis Asma Ahmad Mohtar1, Mohd Fadzil Firdzaus Mohd Nor6, Mohd Talib Latif1, Haris Hafizal Abd Hamid1, Sawal Hamid Md Ali7, Noratiqah Mohd Ariff5, Johary Anuar9†, Fatimah Ahamad4, Azliyana Azhari1, Norfazrin Mohd Hanif1, Mohammed Ahmed Subhi7, Murnira Othman8, Mohd Zaim Mohd Nor9

1 Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
2 Institute of Climate Change, Earth Observatory Center, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
3 Institute of Climate Change, Space Science Centre (ANGKASA), Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
4 Institute of Climate Change, Centre for Tropical System and Climate Change (IKLIM), Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
5 Department of Mathematical Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia. 
6 Institute of Ocean and Earth Sciences, IAS Building, University of Malaya, 50603, Kuala Lumpur, Malaysia.
7 Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia.
8 Institute for Environmental and Development (LESTARI), Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
9 Petaling Jaya City Council, Jalan Yong Shook Lin, 46675 Petaling Jaya, Selangor Darul Ehsan, Malaysia

†Now at Petaling District and Land Office complex, 40150 Shah Alam, Selangor Darul Ehsan, Malaysia


Received: April 26, 2020
Revised: May 13, 2020
Accepted: May 15, 2020

 Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Download Citation: ||https://doi.org/10.4209/aaqr.2020.04.0163 

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Cite this article:

Mohd Nadzir, M.S., Ooi, M.C.G., Alhasa, K.M., Bakar, M.A.A., Mohtar, A.A.A., Nor, M.F.F.M., Latif, M.T., Hamid, H.H.A., Ali, S.H.M., Ariff, N.M., Anuar, J., Ahamad, F., Azhari, A., Hanif, N.M., Subhi, M.A., Othman, M. and Nor. M.Z.M. (2020). The Impact of Movement Control Order (MCO) during Pandemic COVID-19 on Local Air Quality in an Urban Area of Klang Valley, Malaysia. Aerosol Air Qual. Res. 20: 1237–1248. https://doi.org/10.4209/aaqr.2020.04.0163


  • Strong diurnal cycles of measured pollutants during normal days.
  • Concentrations of pollutants dropped during MCO at all site except KD.
  • The increase of particulate matters during MCO at KD was due to the local activities.


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.

Keywords: Movement Control Order; Carbon monoxide; Particulate matters.

Aerosol Air Qual. Res. 20:1237-1248. https://doi.org/10.4209/aaqr.2020.04.0163 

Impact Factor: 2.735

5-Year Impact Factor: 2.827

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