A study on 30 asthmatic children was conducted in Kuala Lumpur. The objective of this study was to study the relationship between respirable particulate (PM10), sulphur dioxide, ozone and various meteorological factors such as humidity, level ofrainfall and temperature with asthma attacks. This study was conducted from 1st September to 31 December 1994. Patients were selected from the Paediatric Unit, Kuala Lumpur Hospital. Questionnaires were used to obtain information from their parents on the history and severity ofasthmatic attacks ofthese patients. Questionnaires were also used to determine if the indoor sources contributed to the attack. Diary cards were used to collect information on the frequency of asthmatic attacks. Each patient's progress was followed through every week during the study period and the attacks were recorded. The data on air quality on the PM10, sulphur dioxide, nitrogen dioxide, carbon monoxide and ozone were collected hourly using the microcomputer system of air monitoring unit from the Universiti Pertanian Malaysia air quality monitoring station located at the City Hall, Kuala Lumpur. The meteorological parameters such as temperature, relative humidity and rain-fall levels were also monitored daily. The asthmatic attack percentage was obtained by dividing the number of attacks in a day with the total number of sample and multiplying by a hundred. Statistical tests indicated that there was a significant correlation between asthmatic attacks and the PM10 concentrations (r=0.73), nitrogen dioxide (r=0.57) and.carbon monoxide (r=0.53) throughout the study period. During the haze episode, more significant correlations between asthmatic attacks, PM10 concentra-tions (0.86), carbon monoxide (0.79) and nitrogen oxide (0.53) were found. Multiple regression statistical test showed that PM10 had the greatest influence on the asthmatic attack rate. The minute respirable particulate which entered the respiratory system of the asthmatics triggered attacks on these patients.
Indoor air quality assessment in residential areas of Al-Hofuf city/Eastern region of Saudi Arabia is investigated through a multi-week multiple sites sampling survey. Critical air pollution indicators, including nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), carbon dioxide (CO2) and total volatile organic compounds (TVOC) as well as temperatures were measured and analyzed during the study period from January to May 2014. Three site-types - roadside, urban and rural - were selected and within each site type, six locations were selected to study the varying indoor/outdoor air quality. The results indicated that NO2 and CO concentrations increased at the starting hours of the day. SO2 concentrations were relatively low and constant. In addition, a strong association between outdoor and indoor air quality was found. Measurements showed that indoor/outdoor ratio for TVOC ranged from 0.8 to 0.99. For CO2, NO2 and SO2, this was 0.92-1.15, 0.5-0.7 and 0.52-0.9, respectively. Finally, the effects of activated carbon (AC) were investigated to assess the extent of the improvement in the indoor air quality. The analysis of data obtained indicated that using locally prepared AC from date stones was an effective way to reduce the indoor air pollution with an overall efficiency of 85.5, while the use of industrial granular AC reduced the air pollutants with an efficiency of less than 0.6. In addition, AC was exposed to an exhaust gas flow to evaluate its elimination potential for high concentrated pollutants. The obtained results demonstrated that AC was also functioning as an efficient absorbent with an overall removal efficiency of 77.8%, even when it was exposed to high concentrations.
Since its first appearance in Wuhan, China at the end of 2019, the new coronavirus (COVID-19) has evolved a global pandemic within three months, with more than 4.3 million confirmed cases worldwide until mid-May 2020. As many countries around the world, Malaysia and other southeast Asian (SEA) countries have also enforced lockdown at different degrees to contain the spread of the disease, which has brought some positive effects on natural environment. Therefore, evaluating the reduction in anthropogenic emissions due to COVID-19 and the related governmental measures to restrict its expansion is crucial to assess its impacts on air pollution and economic growth. In this study, we used aerosol optical depth (AOD) observations from Himawari-8 satellite, along with tropospheric NO2 column density from Aura-OMI over SEA, and ground-based pollution measurements at several stations across Malaysia, in order to quantify the changes in aerosol and air pollutants associated with the general shutdown of anthropogenic and industrial activities due to COVID-19. The lockdown has led to a notable decrease in AOD over SEA and in the pollution outflow over the oceanic regions, while a significant decrease (27% - 30%) in tropospheric NO2 was observed over areas not affected by seasonal biomass burning. Especially in Malaysia, PM10, PM2.5, NO2, SO2, and CO concentrations have been decreased by 26-31%, 23-32%, 63-64%, 9-20%, and 25-31%, respectively, in the urban areas during the lockdown phase, compared to the same periods in 2018 and 2019. Notable reductions are also seen at industrial, suburban and rural sites across the country. Quantifying the reductions in major and health harmful air pollutants is crucial for health-related research and for air-quality and climate-change studies.