Risk Assessment and Air Quality Study during Different Phases of COVID-19 Lockdown in an Urban Area of Klang Valley, Malaysia

Mohd Shahrul Mohd Nadzir, Mohd Zaim Mohd Nor, Mohd Fadzil Firdzaus Mohd Nor, Muhamad Ikram A Wahab, Sawal Hamid Md Ali, Muhsin Kolapo Otuyo, Mohd Aftar Abu Bakar, Lip Huat Saw, Shubhankar Majumdar, Maggie Chel Gee Ooi, Faizal Mohamed, Badrul Akmal Hisham, Haris Hafizal Abd Hamid, Zaki Khaslan, Noratiqah Mohd Ariff, Johary Anuar, Gee Ren Tok, Nurul Asyikin Ya’akop and Mai’izzati Mohd Meswan
Additional contact information
Mohd Shahrul Mohd Nadzir: Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
Mohd Zaim Mohd Nor: Petaling Jaya City Council, Jalan Yong Shook Lin, Petaling Jaya 46675, Selangor, Malaysia
Mohd Fadzil Firdzaus Mohd Nor: Institute of Ocean & Earth Sciences, C308 IAS Building, University Malaya, Kuala Lumpur 50603, Malaysia
Muhamad Ikram A Wahab: Environmental Health and Industrial Safety Program, Faculty of Health Sciences, School of Diagnostic Science and Applied Health, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
Sawal Hamid Md Ali: Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
Muhsin Kolapo Otuyo: Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
Mohd Aftar Abu Bakar: Department of Mathematical Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
Lip Huat Saw: Lee Kong Chian, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Kajang 43000, Selangor, Malaysia
Shubhankar Majumdar: Department of Electronics and Communication Engineering, National Institute of Technology Meghalaya, Shillong 793003, India
Maggie Chel Gee Ooi: Earth Observatory Center, Institute of Climate Change, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
Faizal Mohamed: Faculty of Science and Technology, School of Applied Physics, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
Badrul Akmal Hisham: Department of Orthopedics & Traumatology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, Bandar Tun Razak, Cheras, Kuala Lumpur 56000, Malaysia
Haris Hafizal Abd Hamid: Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
Zaki Khaslan: Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
Noratiqah Mohd Ariff: Department of Mathematical Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
Johary Anuar: Petaling District and Land Office Complex Shah, Shah Alam 40150, Selangor, Malaysia
Gee Ren Tok: Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
Nurul Asyikin Ya’akop: Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
Mai’izzati Mohd Meswan: Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia

Sustainability, 2021, vol. 13, issue 21, 1-22

Abstract: Globally, the COVID-19 pandemic has had both positive and negative impacts on humans and the environment. In general, a positive impact can be seen on the environment, especially in regard to air quality. This positive impact on air quality around the world is a result of movement control orders (MCO) or lockdowns, which were carried out to reduce the cases of COVID-19 around the world. Nevertheless, data on the effects on air quality both during and post lockdown at local scales are still sparse. Here, we investigate changes in air quality during normal days, the MCOs (MCO 1, 2 and 3) and post MCOs, namely the Conditional Movement Control Order (CMCO) and the Recovery Movement Control Order (RMCO) in the Klang Valley region. In this study, we used the air sensor network AiRBOXSense that measures carbon monoxide (CO), nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ) and particulate matter (PM 2.5 and PM 10 ) at Petaling Jaya South (PJS), Kelana Jaya (KJ) and Kota Damansara (KD). The results showed that the daily average concentrations of CO and NO 2 mostly decreased in the order of normal days > MCO (MCO 1, 2 and 3) > CMCO > RMCO. PM 10 , PM 2.5 , SO 2 and O 3 showed a decrease from the MCO to RMCO. PJS showed that air pollutant concentrations decreased from normal days to the lockdown phases. This clearly shows the effects of ‘work from home’ orders at all places in the PJS city. The greatest percentage reductions in air pollutants were observed during the change from normal days to MCO 1 (24% to 64%), while during MCO 1 to MCO 2, the concentrations were slightly increased during the changes of the lockdown phase, except for SO 2 and NO 2 over PJS. In KJ, most of the air pollutants decreased from MCO 1 to MCO 3 except for CO. However, the percentage reduction and increments of the gas pollutants were not consistent during the different phases of lockdown, and this effect was due to the sensor location—only 20 m from the main highway (vehicle emissions). The patterns of air pollutant concentrations over the KD site were similar to the PJS site; however, the percentage reduction and increases of PM 2.5 , O 3 , SO 2 and CO were not consistent. We believe that local burning was the main contribution to these unstable patterns during the lockdown period. The cause of these different changes in concentrations may be due to the relaxation phases during the lockdown at each station, where most of the common activities, such as commuting and industrial activities changed in frequency from the MCO, CMCO and RMCO. Wind direction also affected the concentrations, for example, during the CMCO and RMCO, most of the pollutants were blowing in from the Southeast region, which mostly consists of a city center and industrial areas. There was a weak correlation between air pollutants and the temperature and relative humidity at all stations. Health risk assessment analysis showed that non-carcinogenic risk health quotient (HQ) values for the pollutants at all stations were less than 1, suggesting unlikely non-carcinogenic effects, except for SO 2 (HQ > 1) in KJ. The air quality information showed that reductions in air pollutants can be achieved if traffic and industry emissions are strictly controlled.

Keywords: movement control orders (MCO) phases; air quality; low-cost air quality sensor (LAQS) (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2021
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