The PM 2.5 concentrations dominated the Air Pollutant Index (API) in Malaysia. • There were several reductions on PM 2.5 concentrations during Malaysia Movement Control Order (MCO). • Several red zone areas showed approximately 28.3% reduction of PM 2.5 concentrations. • The Northern Region of Peninsular Malaysia showed the highest average reduction of PM 2.5 concentrations, with 23.7%.

Malaysia has been facing transboundary haze events every year in which the air contains particulate matter, particularly PM10, which affects human health and the environment. Therefore, it is crucial to develop a PM10 forecasting model for early information and warning alerts to the responsible parties in order for them to mitigate and plan precautionary measures during such events. Therefore, this study aimed to develop and compare the best-fitted model for PM10 prediction from the first hour until the next three hours during transboundary haze events. The air pollution data acquired from the Malaysian Department of Environment spanned from the years 2005 until 2014 (excluding years 2007–2009), which included particulate matter (PM10), ozone (O3), nitrogen oxide (NO), nitrogen dioxide (NO), carbon monoxide (CO), sulfur dioxide (SO2), wind speed (WS), ambient temperature (T), and relative humidity (RH) on an hourly basis. Three different stepwise Multiple Linear Regression (MLR) models for predicting the PM10 concentration were then developed based on three different prediction hours, namely t+1, t+2, and t+3. The PM10, t+1 model was the best MLR model to predict PM10 during transboundary haze events compared to PM10,.t+2 and PM10,t+3 models, having the lowest percentage of total error (28%) and the highest accuracy of 46%. A better prediction and explanation of PM10 concentration will help the authorities in getting early information for preserving the air quality, especially during transboundary haze episodes.

Malaysia is a developing country that facing air pollution issues due to industrialization, urbanization activities and population growth. Ozone (O3) is one of the pollutants that can give adverse effects to human health either in long- term or short-term effect. Moreover, it also can interrupt the normal ecosystem and cause extinction in species. This study aims to analyse the annual trends of the concentration of ozone (O3) level for 3-year and the diurnal trends of ozone at Kemaman, Terengganu. One-way Analysis of Variance (ANOVA) revealed that there exists statistically significant different (p<0.05) of O3 concentrations during year 2012-2014. Meanwhile, diurnal trend showed the lowest O3 concentration values in the morning and the highest average concentration values of O3 in the noon, but it starts to decrease gradually in evening and night. The understanding of the ozone trend, yearly and hourly, can helps in tackling the atmospheric pollution problems due to industrialization in Malaysia.

Poor Indoor Air Quality (IAQ) can adversely affect children’s health, comfort and school performance. This study mainly aimed to assess indoor and outdoor air quality status in terms of physical and chemical aspects at nurseries of two higher public institutions. The monitored parameters are temperature (T), relative humidity (RH), air movement (AM), particulate matter (PM), carbon dioxide (CO2) and carbon monoxide (CO) by using Climomaster (RH, T, AM), Dust Trax™ (RSP )and Kanomax IAQ (CO, CO2). The measurement was taken continuously in a period of three days at two nurseries of public institutions. Results show all chemicals contaminants at two nurseries did not exceed the standard except CO2 for indoor concentration. Indoor-Outdoor (I/O) ratio stated that PM10 concentrations were influenced by the outdoor contaminant for both study areas. In conclusion, this study provides useful information for engineers, policy makers and planners to make decision on managing and improving the environment in terms of air quality.

An undesired or hazardous outdoor sound produced by human activities is referred to as environmental noise. For example, the noise emitted through industrial activities and transportation networks such as road, rail and air traffic. In Malaysia, most of the schools located very close to the roadside and near busy places such as cities, shops, and residential areas. This study aims to analyze the environmental noise in terms of spatial and temporal analysis in two primary schools in Terengganu State. The noise monitoring had conducted in two (2) primary schools with different land use; residential area (Batu Rakit Primary School) and commercial area (Paya Bunga Primary School) on the school and non-school days by using Sound Level Meter (SLM). The spatial mapping had constructed by using SketchUp® 2018 and Surfer® version 11 software. The noise level between both study areas was significantly different based on a p-value of less than 0.05. It also surpassed the Department of Environment (DOE) of Malaysia's permitted limit, with the Equivalent Noise Level (LAeq) in residential areas being greater than in commercial areas due to traffic volume and noise from nearby activities. Lastly, the area near the roadside has higher critical noise pollution compared with the location that furthers from the roadside. In conclusion, this study is useful in creating awareness to the public about the noise pollution effect on primary school students and is also can be used for mitigation measures to have a better place for students to study.