Evaluation and Prediction of PM10 and PM2.5 from Road Source Emissions in Kuala Lumpur City Centre

Particulate matter (PM) is one of the major pollutants emitted by vehicles that adversely affect human health and the environment. This study evaluates and predicts concentrations and dispersion patterns of PM10 and PM2.5 in Kuala Lumpur city centre. The OML-Highway model calculates hourly time series of PM10 and PM2.5 concentrations and distribution caused by traffic emissions under different scenarios; business as usual (BAU) and 30% traffic reduction to see the impact of traffic reduction for sustainable traffic management. Continuous PM10 and PM2.5 data from a nearby monitoring station were analysed for the year 2019 and compared with modelled concentrations. Annual average concentration at various locations of interest for PM10 and PM2.5 during BAU runs were in the ranges 41.4–65.9 µg/m3 and 30.4–43.7 µg/m3 respectively, compared to during the 30% traffic reduction run ranging at 40.5–59.5 µg/m3 and 29.9–40.3 µg/m3 respectively. The average concentration of PM10 and PM2.5 at the Continuous Air Quality Monitoring Station (CAQMS) was 36.4 µg/m3 and 28.2 µg/m3 respectively. Strong correlations were observed between the predicted and observed data for PM10 and PM2.5 in both scenarios (p < 0.05). This research demonstrated that the reduction of traffic volume in the city contributes to reducing the concentration of particulate matter pollution

Variation of major air pollutants in different seasonal conditions in an urban environment in Malaysia

Abstract Urban air quality has been deteriorating over time. Pollutant distribution levels in the urban environment may be associated with anthropogenic sources and meteorological conditions. The aim of this study is to determine the variation in concentrations of major air pollutants: carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2), sulphur dioxide (SO2) and particulate matter (PM10), with corresponding seasonal variation in a Malaysian urban environment. Eleven years of data from four selected stations, namely Klang (S1), Petaling Jaya (S2), Shah Alam (S3) and Cheras (S4), were analysed for temporal trend variations (yearly and monthly). Statistical analysis using Openair, an R package open source software, has been conducted to assess pollutants in relation to meteorological conditions. Gas concentrations showed little variation between the study sites apart from NO2, which recorded its highest concentrations at an industrial site, between 23 and 40 ppb, and is associated with industrial and vehicle emissions. Pollutants that show seasonal variations and frequently exceed the Malaysia Ambient Air Quality Standard (MAAQS) and the National Ambient Air Quality Standard (NAAQS) are O3 and PM10, predominantly related to the monsoon seasons. High levels of O3 during the northeast monsoon (January–March) are associated with high levels of the precursors of O3. The concentration of PM10 associated with tropical biomass burning during southwest monsoon. Shipping emissions and power stations are main contributors for higher level of SO2. This study shows regional and local factors contribute to the different type of air pollutant concentrations in urban environment

Spatio-temporal assessment of nocturnal surface ozone in Malaysia

This study aims to determine the level and potential sources of nocturnal surface ozone (NSO) in different regions in Malaysia. Eleven-year (2005–2015) ozone data from 37 continuous air quality monitoring stations throughout Malaysia have been analysed to determine spatio-temporal variations in NSO concentrations. NSO daily maximum concentrations from different regions in Malaysia were used for seasonal variation analysis while linear regression and the Mann-Kendall trend test were used for the annual variation analysis. Average ratios of mean NSO to daytime surface ozone (DSO) for the whole country were found to be 60% of DSO (0.58–0.61). The east coast of the Malaysian Peninsula recorded the highest ratio (70% of DSO) while the central region recorded the lowest concentration (50% of DSO). Titration processes, particularly by NO in the urban areas of the central region, and long transboundary movement of ozone to the east coast are expected to influence the concentration of ozone in these two regions, respectively. On certain occasions, the NSO concentrations (with a maximum value of 137 ppb) exceeded the limit of 100 ppb, the value suggested by Malaysian Air Quality Standard for ambient ozone concentration. The monthly diurnal variation analysis revealed the occurrence of secondary/nocturnal peaks at more than 50% of the stations occurring around 0300–0500 h. The NSO was found to be influenced by the monsoonal season with higher concentrations mainly observed during the boreal winter season. The long-term trend analysis presented the country's overall NSO as having an increasing trend at 27% of the stations

Risks of exposure to ambient air pollutants on the admission of respiratory and cardiovascular diseases in Kuala Lumpur

Epidemiological study of the health consequences due to air pollution exposures is vital, especially in areas with high emissions of pollutants. This study aims to assess the risks of exposure to air pollutants (PM10, CO, NO2 and SO2) on respiratory and cardiovascular admissions in Kuala Lumpur. The quasi-Poisson generalized linear model (GLM) combined with distributed lag non-linear model (DLNM) was used to estimate the associations. The key findings were expressed as the relative risk (RR) with a 95% confidence interval (CI) for single-day and cumulative lag effects (0–7). The highest association of respiratory admissions and PM10 was observed at lag 05 (RR=1.0549, 95%CI=1.0131,1.0984) and NO2 at lag 07 (RR=1.1000, 95%CI=1.0141,1.1931) for an increase of 10 μg/m3 and CO at lag 07 (RR=1.1163, 95%CI=1.0164,1.2260) for an increase of 1 mg/m3 in the concentrations. Changes in levels of NO2 was associated with cardiovascular admissions with the highest RR value was found at lag 01 (RR=1.0491,95%CI=1.0220,1.0770). Adverse respiratory health effects at the population level were observed at low levels of exposure to air pollutants where the current air quality standards were being met. Timely preventive measures should be adopted to lessen the exposure to air pollution, thus modifying the risks to human health

Spatiotemporal Variations of Particulate Matter and their Association with Criteria Pollutants and Meteorology in Malaysia

Fine particulate matter (PM2.5) poses a higher risk to human health than coarse particulate matter (PM10). This study aims to determine the spatiotemporal variations of PM2.5 and PM10 in Malaysia and their association with other criteria pollutants and meteorological factors. Hourly data from air quality monitoring stations for the year 2018 were retrieved from the Malaysian Department of Environment and analysed for temporal and spatial scales according to different regions in Malaysia. Further statistical analyses, such as Spearman’s Rank Correlation and Principal Component Analysis (PCA), were conducted to study the associations between PM2.5 and PM10 with other main criteria air pollutants, as well as meteorological parameters. Higher mean concentrations of PM2.5 (23 ± 8 µg m–3, range = 4.6–158 µg m–3) and PM10 (32 ± 10 µg m–3, range = 6.0–181 µg m–3) were observed in the central region of the Malaysian Peninsula. The diurnal patterns of PM2.5 and PM10 were in a bimodal pattern and influenced by traffic emissions. The highest mean PM2.5 and PM10 concentrations were recorded during the southwest monsoon season, notably in the central region. The Spearman’s Rank Correlation shows that NO2 and CO have a moderately positive correlation (p \u3c 0.01) with PM2.5 (r = 0.47) and PM10 (r = 0.48) in the central regions while all meteorological parameters show significantly weak to very weak correlations with PM. The PCA analysis indicates that the major sources leading to the formation of particulate matter are from the contribution of secondary aerosols and combustion-related sources. The ratio of PM2.5 to PM10 ranged between 0.51 and 0.76 nationwide with the highest mean recorded in the central region (0.72). This study indicates that there is a higher abundance of fine particulate in the ambient air of the urbanised environment and thus a greater likely risk to human health in more developed areas

Rekod jangka panjang kepekatan metana di Malaysia

Gas metana (CH4) adalah gas rumah hijau yang menyebabkan perubahan iklim dan pemanasan dunia. Kajian CH4 dijalankan untuk melihat tren pelepasan CH4 di Malaysia dalam satu jangka masa yang panjang (10 tahun) dari tahun 2000 hingga 2009 dan menilai hubungan CH4 dengan ozon permukaan (O3). Data CH4 daripada 19 stesen pemantauan kualiti udara automatik berterusan Jabatan Alam Sekitar (JAS) di Malaysia telah dianalisis menggunakan analisis statistik dan korelasi Pearson. Hasil kajian mendapati nilai bacaan kepekatan purata bulanan CH4 tertinggi dicatatkan di stesen Larkin, Johor Bahru iaitu 2.61±0.54 ppm. Nilai purata kepekatan CH4 berdasarkan data yang direkodkan di semua stesen di Malaysia adalah 2.00 ppm. Taburan kepekatan CH4 yang lebih tinggi didapati tertumpu di kawasan bandar dan kawasan perindustrian di Selangor, Melaka dan Johor. Analisis korelasi bagi menentukan hubungan CH4 dengan bahan pencemar O3 mendapati 15 stesen menunjukkan korelasi positif yang sangat kecil dan lemah (r 0.05). Stesen Shah Alam didapati menunjukkan korelasi CH4 paling tinggi dengan O3 berbanding stesen lain. Pengetahuan asas berkenaan CH4 dalam udara ambien Malaysia yang ditunjukkan dalam kajian ini boleh digunakan untuk menilai potensi impak CH4 terhadap alam sekitar, perubahan iklim dan kesihatan manusia

Volatile organic compounds and their contribution to ground-level ozone formation in a tropical urban environment

This study aims to determine the trends of volatile organic compound (VOC) concentrations and their potential contribution to O3 formation. The hourly data (August 2017 to July 2018) for 29 VOCs were obtained from three Malaysian Department of Environment continuous air quality monitoring stations with different urban backgrounds (Shah Alam, Cheras, Seremban). The Ozone Formation Potential (OFP) was calculated based on the individual Maximum Incremental Reactivity (MIR) and VOC concentrations. The results showed that the highest mean total VOC concentrations were recorded at Cheras (148 ± 123 μg m−3), within the Kuala Lumpur urban environment, followed by Shah Alam (124 ± 116 μg m−3) and Seremban (86.4 ± 89.2 μg m−3). VOCs such as n-butane, ethene, ethane and toluene were reported to be the most abundant species at all the selected stations, with overall mean concentrations of 16.6 ± 11.9 μg m−3, 12.1 ± 13.3 μg m−3, 10.8 ± 11.9 μg m−3 and 9.67 ± 9.00 μg m−3, respectively. Alkenes (51.3–59.1%) and aromatic hydrocarbons (26.4–33.5%) have been identified as the major contributors to O3 formation in the study areas based on the overall VOC measurements. Relative humidity was found to influence the concentrations of VOCs more than other meteorological parameters. Overall, this study will contribute to further understanding of the distribution of VOCs and their contribution to O3 formation, particularly in the tropical urban environment