Fine particulate matter from brick kilns site and roadside in Lahore, Pakistan: Insight into chemical composition, oxidative potential, and health risk assessment.

Background: Human health is seriously threatened by particulate matter (PM) pollution, which is a major environmental problem. A better indicator of biological responses to PM exposure than its mass alone is the PM "oxidative potential (OP)," or ability to oxidize target molecules. When reactive oxygen species (ROS) are generated in the OP in excess of the antioxidant capacity of body due to PM components such metals and organic species, it causes inflammation, deoxyribonucleic acid (DNA), proteins, and lipids damage. Method: The samples of fine particulate matter (PM2.5) are collected from the brick kiln site and the roadside in Lahore, Pakistan. The organic carbon (OC) and elemental carbon (EC) were estimated by carbon analyzer (DRI 2001A) using the thermal/optical transmittance (TOT) protocol. The water-soluble organic carbon (WSOC) concentration was determined using a total organic carbon analyzer (Shimadzu TOC-L CPN). Ion chromatography (Dionex ICS-900) with a conductivity detector was used to analyze the water-soluble anions (Cl-, NO3-, and SO42-) and cations (NH4+, Na+, K+, Mg2+, and Ca2+). Inductively coupled plasma-mass spectrometry (iCAP TQ ICP-MS, Thermo Scientific) was used to determine the concentrations of metals in the solution. The dithiothreitol (DTT) consumption rate was calculated using a spectrophotometer at a wavelength of 412 nm. Results: The mean concentrations of PM2.5 at the brick kiln site and roadside reported are 509.3 ± 32.3 µg/m3 and 467.5 ± 24.9 µg/m3, and the average OC/EC ratio is 1.9 ± 0.4 and 2.1 ± 0.1. primary organic carbon (POC) contributed more to OC than secondary organic carbon (SOC), which indicated the dominance of primary combustion sources. The anion equivalent (AE) to cation equivalent (CE) ratio indicated that PM2.5 is acidic at both sites due to the dominance of NO3- and SO42-. The DTT consumption rate normalized by PM2.5 mass (DTTm) and DTT consumption rate normalized by air volume (DTTv) of PM2.5 at the roadside samples are higher than at the brick kiln site due to the higher contribution of ionic species to the mass of PM2.5. Carbonaceous species of PM2.5 at both sampling sites are significantly correlated with DTTv of PM2.5, while metallic species behaved differently. The incremental lifetime cancer risk (ILCR) values (lung cancer) of As and Cr at both sampling sites, while the ILCR value of Cd at the roadside samples is exceeding the permissible limits for adults and children. The lifetime average daily dose (LADD) value for adults is higher than that for children, indicating that children are less vulnerable to metals. Conclusion: The concentration of PM2.5 at both sampling sites were exceeding the permissible limits of Pakistan' National Environmental Quality Standard (NEQS) and posing risk to the health of the local population. The POC and SOC contribution to OC at the brick kiln site and roadside in Lahore were 84.6%, 15.4% and 84.4%, 15.6%. POC at both sampling sites were the dominant carbon species indicating the dominance of primary combustion sources. The residence of Lahore poses the lung cancer risk due to Cr, As, and Cd at both sampling sites. The results of this study provide important data and evidence for further evaluation of the potential health risks of PM2.5 from brick kiln site and road side in Pakistan and formulation of efficient air-pollution control measures.

Aerosol Concentrations During Otolaryngology Procedures in a Negative Pressure Isolation Room.

OBJECTIVE: To evaluate the role of a negative pressure room with a high-efficiency particulate air (HEPA) filtration system on reducing aerosol exposure in common otolaryngology procedures. STUDY DESIGN: Prospective quantification of aerosol generation. SETTINGS: Tertiary care. METHODS: The particle concentrations were measured at various times during tracheostomy tube changes with tracheostomy suctioning, nasal endoscopy with suctioning, and fiberoptic laryngoscopy (FOL), which included 5 times per procedure in a negative pressure isolation room with a HEPA filter and additional 5 times in a nonpressure-controlled room without a HEPA filter. The particle concentrations were measured from the baseline, during the procedure, and continued until 30 minutes after the procedure ended. The particle concentrations were compared to the baseline concentrations. RESULTS: The particle concentration significantly increased from the baseline during tracheostomy tube changes (mean difference [MD] 0.80 × 106 p/m3 , p = .01), tracheostomy suctioning (MD 0.78 × 106 p/m3 , p = .004), at 2 minutes (MD 1.29 × 106 p/m3 , p = .01), and 3 minutes (MD 1.3 × 106 p/m3 , p = .004) after suctioning. There were no significant differences in the mean particle concentrations among various time points during nasal endoscopy with suctioning and FOL neither in isolation nor nonpressure-controlled rooms. CONCLUSION: A negative pressure isolation room with a HEPA filter was revealed to be safe for medical personnel inside and outside the room. Tracheostomy tube change with tracheostomy suctioning required an isolation room because this procedure generated aerosol, while nasal endoscopy with suctioning and FOL did not. Aerosol generated in an isolation room was diminished to the baseline after 4 minutes.

Characteristics and Risk Assessment of Environmentally Persistent Free Radicals (EPFRs) of PM2.5 in Lahore, Pakistan.

Environmentally persistent free radicals (EPFRs) are an emerging pollutant and source of oxidative stress. Samples of PM2.5 were collected at the urban sites of Lahore in both winter and summertime of 2019. The chemical composition of PM2.5, EPRF concentration, OH radical generation, and risk assessment of EPFRs in PM2.5 were evaluated. The average concentration of PM2.5 in wintertime and summertime in Lahore is 15 and 4.6 times higher than the national environmental quality standards (NEQS) of Pakistan and WHO. The dominant components of PM2.5 are carbonaceous species. The concentration of EPFRs and reactive oxygen species (ROS), such as OH radicals, is higher in the winter than in the summertime. The secondary inorganic ions do not contribute to the generation of OH radicals, although the contribution of SO42+, NO3-, and NH4+ to the mass concentration of PM2.5 is greater in summertime. The atmospheric EPFRs are used to evaluate the exposure risk. The EPFRs in PM2.5 and cigarette smoke have shown similar toxicity to humans. In winter and summer, the residents of Lahore inhaled the amount of EPFRs equivalent to 4.0 and 0.6 cigarettes per person per day, respectively. Compared to Joaquin County, USA, the residents of Lahore are 1.8 to 14.5 times more exposed to EPFRs in summer and wintertime. The correlation analysis of atmospheric EPFRs (spin/m3) and carbonaceous species of PM2.5 indicates that coal combustion, biomass burning, and vehicle emissions are the possible sources of EPFRs in the winter and summertime. In both winter and summertime, metallic and carbonaceous species correlated well with OH radical generation, suggesting that vehicular emissions, coal combustion, and industrial emissions contributed to the OH radical generation. The study's findings provide valuable information and data for evaluating the potential health effects of EPFRs in South Asia and implementing effective air pollution control strategies.

Chemical Composition, Sources, and Health Risk Assessment of PM2.5 and PM10 in Urban Sites of Bangkok, Thailand.

Of late, air pollution in Asia has increased, particularly in built-up areas due to rapid industrialization and urbanization. The present study sets out to examine the impact that pollution can have on the health of people living in the inner city of Bangkok, Thailand. Consequently, in 2021, fine particulate matter (PM2.5) and coarse particulate matter (PM10) chemical composition and sources are evaluated at three locations in Bangkok. To identify the possible sources of such particulates, therefore, the principal component analysis (PCA) technique is duly carried out. As determined via PCA, the major sources of air pollution in Bangkok are local emission sources and sea salt. The most significant local sources of PM2.5 and PM10 in Bangkok include primary combustion, such as vehicle emissions, coal combustion, biomass burning, secondary aerosol formation, industrial emissions, and dust sources. Except for the hazard quotient (HQ) of Ni and Mn of PM2.5 for adults, the HQ values of As, Cd, Cr, Mn, and Ni of both PM2.5 and PM10 were below the safe level (HQ = 1) for adults and children. This indicates that exposure to these metals would have non-carcinogenic health effects. Except for the carcinogenic risk (HI) value of Cr of PM2.5 and PM10, which can cause cancer in adults, at Bangna and Din Daeng, the HI values of Cd, Ni, As, and Pb of PM2.5 and PM10 are below the limit set by the U.S. Environmental Protection Agency (U.S. EPA). Ni and Mn pose non-carcinogenic risks, whereas Cr poses carcinogenic risks to adults via inhalation, a serious threat to the residents of Bangkok.