Air pollution is the culprit to yearly millions of deaths worldwide, deteriorating human health. What is not yet clear is the impact of environmental factors on susceptibility to getting infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The study aimed to determine associations between air quality, meteorological factors, and COVID-19 cases in Kuala Lumpur, Malaysia. Air pollutants and meteorological data in 2018–2020 were obtained from the Department of Environment Malaysia, while daily new COVID-19 cases in 2020 were obtained from the Ministry of Health Malaysia. Data collected were statistically analyzed using the Statistical Package for Social Sciences (SPSS). There were significant differences between PM10, PM2.5, SO2, NO2, CO, O3, and solar radiation in 2019 and 2020 since movement control order (MCO) was implemented on 18 March 2020. Spearman’s correlation test showed that COVID-19 cases were positively correlated with PM10 (r = 0.131, p < 0.001), PM2.5 (r = 0.151, p < 0.001), SO2 (r = 0.091, p = 0.003), NO2 (r = 0.228, p < 0.001), CO (r = 0.269, p = 0.001), and relative humidity (RH) (r = 0.106, p = 0.001), whereas ambient temperature (AT) was negatively correlated with COVID-19 cases (r = -0.118, p < 0.001). Further, multiple linear regression suggested that NO2 and AT (R2 = 0.071, p < 0.001, f2 = 0.08) were the most significant air pollutant and meteorological factors that influenced the incidence of COVID-19 cases in Kuala Lumpur. In general, better air quality, lower RH, higher AT, along with the targeted approach implemented thus far, have proven to curb the spread of this virus infection in Malaysia. This study supports future research in studies documented to understand the potential of transmission, survival, and infection of SARS-CoV-2.

This study aimed to assess the association of exposure to particle-bound (PM_2.5) polycyclic aromatic hydrocarbons (PAHs) with potential genotoxicity and cancer risk among children living near the petrochemical industry and comparative populations in Malaysia. PM_2.5 samples were collected using a low-volume sampler for 24 h at three primary schools located within 5 km of the industrial area and three comparative schools more than 20 km away from any industrial activity. A gas chromatography–mass spectrometer was used to determine the analysis of 16 United States Environmental Protection Agency (USEPA) priority PAHs. A total of 205 children were randomly selected to assess the DNA damage in buccal cells, employing the comet assay. Total PAHs measured in exposed and comparative schools varied, respectively, from 61.60 to 64.64 ng m⁻³ and from 5.93 to 35.06 ng m⁻³. The PAH emission in exposed schools was contributed mainly by traffic and industrial emissions, dependent on the source apportionment. The 95th percentiles of the incremental lifetime cancer risk estimated using Monte Carlo simulation revealed that the inhalation risk for the exposed children and comparative populations was 2.22 × 10⁻⁶ and 2.95 × 10⁻⁷, respectively. The degree of DNA injury was substantially more severe among the exposed children relative to the comparative community. This study reveals that higher exposure to PAHs increases the risk of genotoxic effects and cancer among children.

The indoor environment is a major source of human exposure to pollutants. Some pollutants can have concentrations that are several times higher indoors than outdoors. Prolonged exposure may lead to adverse biologic effects, even at low concentrations. Several studies done in Malaysia had underlined the role of indoor air pollution in affecting respiratory health, especially for school-aged children. A critical review was conducted on the quantitative literature linking indoor air pollution with respiratory illnesses among school-aged children. This paper reviews evidence of the association between indoor air quality (IAQ) and its implications on respiratory health among Malaysian school-aged children. This review summarizes six relevant studies conducted in Malaysia for the past 10 years. Previous epidemiologic studies relevant to indoor air pollutants and their implications on school-aged children’s respiratory health were obtained from electronic database and included as a reference in this review. The existing reviewed data emphasize the impact of IAQ parameters, namely, indoor temperature, ventilation rates, indoor concentration of carbon dioxide (CO₂), carbon monoxide (CO), particulate matters (PM), volatile organic compounds (VOCs), nitrogen dioxide (NO₂) and airborne microbes, on children’s respiratory health. The study found that most of the Malaysian school-aged children are exposed to the inadequate environment during their times spent either in their houses or in their classrooms, which is not in compliance with the established standards. Children living in households or studying in schools in urban areas are more likely to suffer from respiratory illnesses compared with children living in homes or studying in schools in rural areas.

Some of the environmental toxicants from air pollution include particulate matter (PM₁₀), fine particulate matter (PM_2.5), and ultrafine particles (UFP). Both short- and long-term exposure could result in various degrees of respiratory health outcomes among exposed persons, which rely on the individuals’ health status.Methods. In this paper, we highlight a review of the studies that have used biomarkers to understand the association between air particles exposure and the development of respiratory problems resulting from the damage in the respiratory system. Data from previous epidemiological studies relevant to the application of biomarkers in respiratory system damage reported from exposure to air particles are also summarized.Results. Based on these analyses, the findings agree with the hypothesis that biomarkers are relevant in linking harmful air particles concentrations to increased respiratory health effects. Biomarkers are used in epidemiological studies to provide an understanding of the mechanisms that follow airborne particles exposure in the airway. However, application of biomarkers in epidemiological studies of health effects caused by air particles in both environmental and occupational health is inchoate.Conclusion. Biomarkers unravel the complexity of the connection between exposure to air particles and respiratory health.

Indoor air quality (IAQ) has been the object of several studies due to its adverse health effects on children.Methods. A cross-sectional comparative study was carried out among Malay children in Balakong (2 studied preschools) and Bangi (2 comparative preschools), Selangor, with the aims of determining IAQ and its association with respiratory health. 61 and 50 children aged 5-6 years were selected as studied and comparative groups. A questionnaire was used to obtain an exposure history and respiratory symptoms. Lung function test was carried out. IAQ parameters obtained include indoor concentration of particulate matter (PM), volatile organic compounds (VOCs), carbon monoxide (CO), carbon dioxide (CO₂), temperature, air velocity (AV), and relative humidity.Results. There was a significant difference between IAQ in studied and comparative preschools for all parameters measured(P<0.001)except for CO₂and AV. Studied preschools had higher PM and CO concentration. FVC, FEV₁, FVC% and FEV₁% predicted values were significantly lower among studied group. Exposures to PM, VOCs, and CO were associated with wheezing.Conclusion. The finding concluded that exposures to poor IAQ might increase the risk of getting lung function abnormality and respiratory problems among study respondents.

This study aimed to investigate the association between particulate PAHs exposure and DNA damage in Malaysian schoolchildren in heavy traffic (HT) and low traffic (LT) areas. PAH samples at eight schools were collected using a low volume sampler for 24 h and quantified using Gas Chromatography-Mass Spectrometry. Two hundred and twenty-eight buccal cells of children were assessed for DNA damage using Comet Assay. Monte-Carlo simulation was performed to determine incremental lifetime cancer risk (ILCR) and to check the uncertainty and sensitivity of the estimated risk. Total PAH concentrations in the schools in HT area were higher than LT area ranging from 4.4 to 5.76 ng m⁻³ and 1.36 to 3.79 ng m⁻³, respectively. The source diagnostic ratio showed that PAHs in the HT area is pyrogenic, mainly from diesel emission. The 95th percentile of the ILCR for children in HT and LT area were 2.80 × 10⁻⁷ and 1.43 × 10⁻⁷, respectively. The degree of DNA damage was significantly more severe in children in the HT group compared to LT group. This study shows that total indoor PAH exposure was the most significant factor that influenced the DNA damage among children. Further investigation of the relationship between PAH exposure and genomic integrity in children is required to shed additional light on potential health risks.