Browsing by Author "Nasir, Zaheer Ahmad"

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    Bioaerosols emission characteristics from wastewater treatment aeration tanks and associated health risk exposure assessment during autumn and winter
    (Elsevier, 2022-08-22) Zhao, Xiao-yan; An, Dong-zi; Liu, Man-li; Ma, Jia-xin; Ali, Wajid; Zhu, Hao; Li, Ming; Ai, Xiao-jun; Nasir, Zaheer Ahmad; Garcia Alcega, Sonia; Coulon, Frederic; Yan, Cheng
    Aeration tanks from activated sludge wastewater treatment plants (WWTPs) can release a large amount of bioaerosols that can pose health risks. However, risk characterization of bioaerosols emissions form wastewater treatment plants is currently not systematically carried out and still in its infancy. Therefore, this study investigated emission characteristic of two indicator model bioaerosols Staphylococcus aureus and Escherichia coli, emitted from aeration tanks of a municipal WWTP. Monte Carlo simulation was then used to quantitatively assess microbial risk posed by different aeration modes under optimistic and conservative estimates. Further to this, two different exposure scenarios were considered during 3 days sampling campaign in autumn and winter. Results showed that the bioaerosol concentration from microporous aeration tank (20–262 CFU m−3) was one order of magnitude lower than rotating disc aeration tank. Average aerosolization rate was 7.5 times higher with mechanical aeration mode. Health risks of exposed populations were 0.4 and 9.6 times higher in winter than in autumn for E. coli and S. aureus bioaerosol, respectively. Health risks of staff members were 10 times higher than academic visitors. Interesting results were observed for academic visitors without personal protective equipment (PPE) respectively exposed to S. aureus and E. coli bioaerosol in autumn and winter: while the derived infection risk met the United States Environmental Protection Agency (U.S. EPA) benchmark under optimistic estimation, the disease risk burden was over the World Health Organization (WHO) benchmark under conservative estimation. These revealed that only satisfying one of the two benchmarks didn't mean absolute acceptable health risk. This study could facilitate the development of better understanding of bioaerosol quantitative assessment of risk characterizations and corresponding appropriate risk control strategies for wastewater utilities.
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    Characterization of metals in feed, litter and air of intensive poultry farming facilities
    (Researchers Links, 2023-12-01) Yasmeen, Roheela; Hafeez, Faheem; Ammara, Umme; Younas, Rubab; Ahmad, Sibtain; Ali, Zulfiqar; Nasir, Zaheer Ahmad
    Poultry industry is progressing worldwide due to cheap sources of proteins and it is also considered as the center of various organic and inorganic emissions. The current study was designed to see the release of different metals from the poultry farms. Air samples both from indoor and outdoor along with the litter and feed samples of ten poultry houses were collected from the outskirts of Lahore, Punjab, Pakistan. Poultry farms were varied in feed and grouped into three categories: Group A (using Feed A), Group B (using Feed B) and Group C (using Feed C). All collected samples were digested with aqua regia and analyzed by Inductively Coupled Plasma Atomic Mass Spectroscopy (ICP-MS). Fourteen metals were detected and categorized as essential (Calcium (Ca), Potassium (K), Sodium (Na), Phosphorus (P), Magnesium (Mg)), trace (Zinc (Zn), Copper (Cu), Iron (Fe), Manganese (Mn)) and heavy metals (Cadmium (Cd), Chromium (Cr), Mercury (Hg), Nickel (Ni), Lead (Pb)). In general, the concentration of all essential, trace, and heavy metals was found to be highest in feed followed by litter and air samples. However, Cr, Hg and Pb were higher in litter samples of group A as compared to feed and air. All the samples were statistically analyzed using one way ANOVA. A significant difference of feed was present with litter and air samples within groups (p<0.05) however, no significant differences were recorded among different groups. Overall it was noticed that the concentration of metals in feed samples were reflecting in litter and air. So, there is a need to ensure intervention and management policies in intensive poultry farming facilities to establish standards for metal in feed to reduce their bioaccumulation in the environment.
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    Exposure to benzene, toluene, ethylbenzene, and xylene (BTEX) at Nigeria's petrol stations: a review of current status, challenges and future directions
    (Frontiers, 2024-03-25) Anigilaje, Emmanuel Ademola; Nasir, Zaheer Ahmad; Walton, Christopher
    Introduction: In Nigeria, because of increasing population, urbanization, industrialization, and auto-mobilization, petrol is the most everyday non-edible commodity, and it is the leading petroleum product traded at the proliferating Nigeria's petrol stations (NPSs). However, because of inadequate occupational health and safety (OHS) regulatory measures, working at NPSs exposes petrol station workers (PSWs) to a large amount of hazardous benzene, toluene, ethylbenzene, and xylene (BTEX) compounds. Methods: Studies on BTEX exposures among Nigerian PSWs are scarce. Thus, constraints in quantifying the health risks of BTEX limit stakeholders' ability to design practical risk assessment and risk control strategies. This paper reviews studies on the OHS of Nigerian PSWs at the NPSs. Results: Although knowledge, attitude, and practices on OHS in NPSs vary from one Nigeria's study setting to another, generally, safety practices, awareness about hazards and personal protective equipment (PPE), and the use of PPE among PSWs fell below expectations. Additionally, air quality at NPSs was poor, with a high content of BTEX and levels of carbon monoxide, hydrogen sulfide, particulate matter, and formaldehyde higher than the World Health Organization guideline limits. Discussion: Currently, regulatory bodies' effectiveness and accountability in safeguarding OHS at NPSs leave much to be desired. Understanding the OHS of NPSs would inform future initiatives, policies, and regulations that would promote the health and safety of workers at NPSs. However, further studies need to be conducted to describe the vulnerability of PSWs and other Nigerians who are occupationally exposed to BTEX pollution. More importantly, controlling air pollution from hazardous air pollutants like BTEX is an essential component of OHS and integral to attaining the Sustainable Development Goals (SDG) 3, 7, and 11.
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    Quantitative health risk assessment of microbial hazards from water sources for community and self-supply drinking water systems
    (Elsevier, 2023-12-26) Yan, Cheng; Wan, Wei-di; Wang, Rui-ning; Lai, Tian-nuo; Ali, Wajid; He, Shan-shan; Liu, Sai; Nasir, Zaheer Ahmad; Coulon, Frederic
    In low and medium income countries (LMIC) drinking water sources (wells and boreholes) often contain a high number of pathogenic microorganisms, that can pose significant human and environmental health risks. In this study, a quantitative microbial risk assessment approach based on existing literature was conducted to evaluate and compare the quantitative health risks associated with different age groups using various drinking water supply systems. Results showed that both community-supply and self-supply modes exhibit similar levels of risk. However, the self-supply water source consistently showed higher risks compared to the community-supply one. Borehole water was found to be a more suitable option than well water, consistently showing between 5 and 8 lower health risks for E. coli and fecal coliform levels, respectively. The sensitivity analysis further showed the importance of prioritizing the reduction of E. coli concentration in well water and fecal coliform concentration in borehole water. This study offers a fresh perception on quantifying the impact of exposure concentration and age groups, shedding light on how they affect environmental health risks. These findings provide valuable insights for stakeholders involved in the management and protection of water sources.
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    Quantitative SARS-CoV-2 exposure assessment for workers in wastewater treatment plants using Monte-Carlo simulation
    (Elsevier, 2023-11-16) Yan, Cheng; Hu, Yi-ning; Gui, Zi-cheng; Lai, Tian-nuo; Ali, Wajid; Wan, Nian-hong; He, Shan-shan; Liu, Sai; Li, Xiang; Jin, Ting-xu; Nasir, Zaheer Ahmad; Garcia Alcega, Sonia; Coulon, Frederic
    Several studies on COVID-19 pandemic have shown that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) originating from human stool are detected in raw sewage for several days, leading to potential health risks for workers due to the production of bioaerosols and droplets during wastewater treatment process. In this study, data of SARS-CoV-2 concentrations in wastewater were gathered from literatures, and a quantitative microbial risk assessment with Monte Carlo simulation was used to estimate the daily probability of infection risk through exposure to viable infectious viral airborne particles of the workers during four seasons and under six environmental conditions. Inhalation of bioaerosols and direct ingestion of wastewater droplets were selected as exposure pathways. Spearman rank correlation coefficients were used for sensitivity analysis to identify the variables with the greatest influence on the infection risk probability. It was found that the daily probability of infection risk decreased with temperature (T) and relative humidity (RH) increase. The probability of direct droplet ingestion exposure pathway was higher than that of the bioaerosol inhalation pathway. The sensitivity analysis indicated that the most sensitive variable for both exposure pathways was the concentration of SARS-CoV-2 in stool. So, appropriate aeration systems, covering facilities, and effective ventilation are suggested to implement in wastewater treatment plants (WWTPs) to reduce emission concentration. Further to this, the exposure time (t) had a larger variance contribution than T and RH for the bioaerosol inhalation pathway. Implementing measures such as adding more work shifts, mandating personal protective equipment for all workers, and implementing coverage for treatment processes can significantly reduce the risk of infection among workers at WWTPs. These measures are particularly effective during environmental conditions with low temperatures and humidity levels.
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    Rapid measurement tools or fast identification of bioaerosols
    (Adjacent Digital Politics Ltd, 2023-02-23) Whitby, Corinne; Ferguson, Robert M. W.; Dumbrell, Alex; Colbeck, Ian; Coulon, Frederic; Nasir, Zaheer Ahmad
    Bioaerosols are complex mixtures of airborne particles of biological origin (BioPM), which vary in size (~0.05-100 μm) and composition (viruses, bacteria, fungi/mould, pollen, cell fragments, and endotoxins). Many bioaerosols are of inhalable size (< 100 μm), but those < 10 μm are respirable and can penetrate deep into the respiratory system, making them a primary health concern(6). In addition to causing infectious diseases (e.g. tuberculosis and COVID-19), bioaerosols are associated with non-infectious diseases, such as hypersensitivity, allergies, chronic obstructive pulmonary disease (COPD) and asthma, that cause significant mortality and morbidity(4,7). Antimicrobial resistance (AMR) also poses an emerging and uncertain threat to public health worldwide, yet, AMR in bioaerosols is generally ignored leaving a major blindspot in the OneHealth approach to fighting AMR.
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    Towards developing an indoor emissions inventory for the UK: challenges and future directions
    (Royal Society of Chemistry (RSC), 2024) Mazzeo, Andrea; Pfrang, Christian; Nasir, Zaheer Ahmad
    The global attention on indoor air quality is progressively increasing as people spend ca. 80 to 90% of their lives indoors. Therefore, a substantial fraction of exposure to air pollution occurs in different indoor environments. However, there is a lack of information on how different time and activity dependent sources and built environment characteristics affect air pollutant emissions and their distribution. There is an urgent need to develop indoor emissions inventories to estimate the contribution of multiple and time-dependent sources and activities to air pollutant emissions. This paper reviews the current state-of-the-art of indoor air pollution research in the UK, categorises the published literature according to pollutant types, built environments and activities, provides an overview of typical levels of indoor air pollutants with a focus on UK-specific measurements and identifies the research gaps and future directions to progress towards developing indoor emission inventories. In the UK, researchers have investigated indoor air quality since the nineties producing many studies from different perspectives. However, a cohesive methodological approach is lacking in most of the studies. Several important sources/species are not represented, ancillary information relating to environment characteristics (volumes and ventilation) and occupants' behaviours during the measurements is not reported and too little information on the indoor–outdoor continuum is provided. Despite the gaps identified, the existing evidence base on indoor air pollution in the UK can be categorised in an easy-to-use database of indoor air pollutant concentrations and characteristic emission rates for specific activities, pollutants and environments. This will provide a platform for designing standardised approaches for indoor air quality measurements and the development of activity-based indoor emission inventories, which will be a step-change in indoor air pollution research in the UK and globally.