Multi-channel surface-enhanced Raman spectroscopy (SERS) platform for pollutant detection in water fabricated on polydimethylsiloxane.

A miniature multi-channel surface-enhanced Raman scattering (SERS) sensor based on polydimethylsiloxane (PDMS) is constructed to achieve rapid delivery of polluted water and specific identification of multiple components. Hg2+, organic pollutants, and sodium nitrite are successfully identified by the multi-channel SERS sensor using Cy5, cyclodextrin, and urea in the corresponding detection area. This multi-channel sensor exhibits excellent sensitivity and specificity, with detection limits of 3.2 × 10-10 M for Hg2+, 1.0 × 10-8 M for aniline, 6.9 × 10-9 M for diphenylamine, 9.1 × 10-8 M for PCB-77, and 7.5 × 10-9 M for pyrene, and 5.0 × 10-7 M for sodium nitrite. Compared with traditional analysis techniques, this method exhibited excellent recovery for the water pollutants ranging from 82.1 to 115.8%. The PDMS-based microchannel allows for simultaneous and rapid identification of multiple environmental pollutants, offering a portable detection method for emergency testing of environmental pollutants and routine determination of water pollutants.

Microbial Immobilized Enzyme Biocatalysts for Multipollutant Mitigation: Harnessing Nature's Toolkit for Environmental Sustainability.

The ever-increasing presence of micropollutants necessitates the development of environmentally friendly bioremediation strategies. Inspired by the remarkable versatility and potent catalytic activities of microbial enzymes, researchers are exploring their application as biocatalysts for innovative environmental cleanup solutions. Microbial enzymes offer remarkable substrate specificity, biodegradability, and the capacity to degrade a wide array of pollutants, positioning them as powerful tools for bioremediation. However, practical applications are often hindered by limitations in enzyme stability and reusability. Enzyme immobilization techniques have emerged as transformative strategies, enhancing enzyme stability and reusability by anchoring them onto inert or activated supports. These improvements lead to more efficient pollutant degradation and cost-effective bioremediation processes. This review delves into the diverse immobilization methods, showcasing their success in degrading various environmental pollutants, including pharmaceuticals, dyes, pesticides, microplastics, and industrial chemicals. By highlighting the transformative potential of microbial immobilized enzyme biocatalysts, this review underscores their significance in achieving a cleaner and more sustainable future through the mitigation of micropollutant contamination. Additionally, future research directions in areas such as enzyme engineering and machine learning hold immense promise for further broadening the capabilities and optimizing the applications of immobilized enzymes in environmental cleanup.

Analysis of China's PM2.5 and ozone coordinated control strategy based on the observation data from 2015 to 2020.

The coordinated control of PM2.5 and ozone has become the strategic goal of national air pollution control. Considering the gradual decline in PM2.5 concentration and the aggravation of ozone pollution, a better understanding of the coordinated control of PM2.5 and ozone is urgently needed. Here, we collected and sorted air pollutant data for 337 cities from 2015 to 2020 to explore the characteristics of PM2.5 and ozone pollution based on China's five major air pollution regions. The results show that it is necessary to continue to strengthen the emission reduction in PM2.5 and ozone precursors, and control NOx and VOCs while promoting a dramatic emission reduction in PM2.5. The primary method of curbing ozone pollution is to strengthen the emission control of VOCs, with a long-term strategy of achieving substantial emission reductions in NOx, because VOCs and NOx are also precursors to PM2.5; hence, their reductions also contribute to the reduction in PM2.5. Therefore, the implementation of a multipollutant emission reduction control strategy aimed at the prevention and control of PM2.5 and ozone pollution is the only means to realize the coordinated control of PM2.5 and ozone.

Mixtures of persistent organic pollutants and ovarian function in women undergoing IVF.

RESEARCH QUESTION: Do internal levels of persistent organic pollutants (POP) in serum and follicular fluid affect ovarian function of women attending IVF? DESIGN: This cohort study included 136 women undergoing IVF in the assisted reproductive technology (ART) service of University Hospital from Nantes (France). Representative POP were measured using gas and liquid chromatography coupled with tandem mass spectrometry. Polyfluoroalkylated and perfluoroalkylated substances were measured in serum and polychlorinated biphenyls and organochlorinated pesticides in follicular fluid. Statistical associations between POP and ovarian reserve markers (anti-Müllerian Hormone [AMH] and antral follicle count [AFC], and ovarian responsiveness markers (Ovarian Sensitivity Index [OSI] and Follicular Output RaTe [FORT]), were explored in single and multipollutant regression models. RESULTS: Twenty-seven out of 53 POP congeners were frequently detected in almost all women attending IVF. Adjusted models did not show statistically significant associations between POP and ovarian reserve markers. Positive associations were found between some POP, i.e. hexachlorobenzene with FORT (ß 0.42, 95% CI 0.13 to 0.71, P = 0.005) or PCB52 with Ovarian Sensitivity Index (ß 0.22; 95% CI, 0.07 to 0.38, P = 0.005). Negative associations between some polyfluoroalkylated and perfluoroalkylated substances, PCB189 and trans-nonachlor with AFC and AMH were found among current smokers. CONCLUSIONS: Globally, associations between POP and the markers of ovarian function or responsiveness were lacking. Nonetheless, the stratification analysis suggested that current smoking could be a risk modifier, and extension of the study to a larger population sample size is needed.

Polymerization State of Vanadyl Species Affects the Catalytic Activity and Arsenic Resistance of the V2O5-WO3/TiO2 Catalyst in Multipollutant Control of NOx and Chlorinated Aromatics.

The conventional V2O5-WO3/TiO2 catalyst suffers severely from arsenic poisoning, leading to a significant loss of catalytic activity. The doping of Al or Mo plays an important role in promoting the arsenic resistance on NH3 selective catalytic reduction (NH3-SCR), but their promotion mechanism remains in debate and has yet to be explored in multipollutant control (MPC) of NOx and chlorinated organics. Herein, our experimental characterizations and density functional theory (DFT) calculations confirmed that arsenic species preferentially adsorb on both Al and Mo to form arsenate, thereby avoiding bonding to the catalytically active V sites. More importantly, Al doping partially converted the polymeric vanadyl species into monomeric ones, thereby inhibiting the near-surface and bulk lattice oxygen mobility of the V2O5-WO3/TiO2 catalyst, while Mo doping resulted in vanadyl polymerization with an enriched V5+ chemical state and exhibited superior MPC activity and COx selectivity. Our work shows that antipoisoning catalysts can be designed with the combination of site protection and occurrence state modification of the active species.

Design of Bifunctional Cu-SSZ-13@Mn2Cu1Al1Ox Core-Shell Catalyst with Superior Activity for the Simultaneous Removal of VOCs and NOx.

Synchronous control of volatile organic compounds (VOCs) and nitrogen oxides (NOx) is of great importance for ozone and PM2.5 pollution control. Balancing VOC oxidation and the NH3-SCR reaction is the key to achieving the simultaneous removal of these two pollutants. In this work, a vertically oriented Mn2Cu1Al1Ox nanosheet is grown in situ on the surface of Cu-SSZ-13 to synthesize a core-shell bifunctional catalyst (Cu-SSZ-13@Mn2Cu1Al1Ox) with multiple active sites. The optimized Cu-SSZ-13@Mn2Cu1Al1Ox catalyst delivered excellent performance for the simultaneous removal of VOCs and NOx with both 100% conversion at 300 °C in the presence of 5% water vapor. Physicochemical characterization and density functional theory (DFT) calculations revealed that Cu-SSZ-13@Mn2Cu1Al1Ox possesses more surface acidity and oxygen vacancies. The charge transfer between the core and shell is the intrinsic reason for the improved activity for both VOC and NOx removal. The molecular orbital theory is used to explain the different adsorption energies due to the different bonding modes between the core-shell and mixed individual catalysts. This work provides a novel strategy for designing efficient catalysts for the simultaneous removal of VOCs and NOx or other multiple pollutants.

Exposure to Volatile Organic Compounds Is Associated with Hypertension in Black Adults: The Jackson Heart Study.

BACKGROUND: The prevalence of hypertension is higher among Black adults than among White and Hispanic adults. Nevertheless, reasons underlying the higher rates of hypertension in the Black population remain unclear but may relate to exposure to environmental chemicals such as volatile organic compounds (VOCs). METHODS: We evaluated the associations of blood pressure (BP) and hypertension with VOC exposure in non-smokers and smokers in a subgroup of the Jackson Heart Study (JHS), consisting of 778 never smokers and 416 age- and sex-matched current smokers. We measured urinary metabolites of 17 VOCs by mass spectrometry. RESULTS: After adjusting for covariates, we found that amoong non-smokers, metabolites of acrolein and crotonaldehyde were associated with a 1.6 mm Hg (95%CI: 0.4, 2.7; p = 0.007) and a 0.8 mm Hg (95%CI: 0.01, 1.6; p = 0.049) higher systolic BP, and the styrene metabolite was associated with a 0.4 mm Hg (95%CI: 0.09, 0.8, p = 0.02) higher diastolic BP. Current smokers had 2.8 mm Hg (95% CI 0.5, 5.1) higher systolic BP. They were at higher risk of hypertension (relative risk = 1.2; 95% CI, 1.1, 1.4), and had higher urinary levels of several VOC metabolites. Individuals who smoke had higher levels of the urinary metabolites of acrolein, 1,3-butadiene, and crotonaldehyde and were associated with higher systolic BP. The associations were stronger among participants who were <60 years of age and male. Using Bayesian kernel machine regression to assess the effects of multiple VOC exposures, we found that the relationship between VOCs and hypertension among non-smokers was driven primarily by acrolein and styrene in non-smokers, and crotonaldehyde in smokers. CONCLUSIONS: Hypertension in Black individuals may be attributed, in part, to VOC exposure from the environment or tobacco smoke.

Relationship of long-term air pollution exposure with asthma and rhinitis in Italy: an innovative multipollutant approach.

BACKGROUND: air pollution is a complex mixture; novel multipollutant approaches could help understanding the health effects of multiple concomitant exposures to air pollutants. AIM: to assess the relationship of long-term air pollution exposure with the prevalence of respiratory/allergic symptoms and diseases in an Italian multicenter study using single and multipollutant approaches. METHODS: 14420 adults living in 6 Italian cities (Ancona, Pavia, Pisa, Sassari, Turin, Verona) were investigated in 2005-2011 within 11 different study cohorts. Questionnaire information about risk factors and health outcomes was collected. Machine learning derived mean annual concentrations of PM10, PM2.5, NO2 and mean summer concentrations of O3 (µg/m3) at residential level (1-km resolution) were used for the period 2013-2015. The associations between the four pollutants and respiratory/allergic symptoms/diseases were assessed using two approaches: a) logistic regression models (single-pollutant models), b) principal component logistic regression models (multipollutant models). All the models were adjusted for age, sex, education level, smoking habits, season of interview, climatic index and included a random intercept for cohorts. RESULTS: the three-year average (± standard deviation) pollutants concentrations at residential level were: 20.3 ± 6.8 µg/m3 for PM2.5, 29.2 ± 7.0 µg/m3 for PM10, 28.0 ± 11.2 µg/m3 for NO2, and 70.9 ± 4.3 µg/m3 for summer O3. Through the multipollutant models the following associations emerged: PM10 and PM2.5 were related to 14-25% increased odds of rhinitis, 23-34% of asthma and 30-33% of night awakening; NO2 was related to 6-9% increased odds of rhinitis, 7-8% of asthma and 12% of night awakening; O3 was associated with 37% increased odds of asthma attacks. Overall, the Odds Ratios estimated through the multipollutant models were attenuated when compared to those of the single-pollutant models. CONCLUSIONS: this study enabled to obtain new information about the health effects of air pollution on respiratory/allergic outcomes in adults, applying innovative methods for exposure assessment and multipollutant analyses.

Does air pollution confound associations between environmental noise and cardiovascular outcomes? - A systematic review.

BACKGROUND: Exposure to environmental noise is associated with adverse health effects, but there is potential for confounding and interaction with air pollution, particularly where both exposures arise from the same source, such as transport. OBJECTIVES: To review evidence on confounding and interaction of air pollution in relation to associations between environmental noise and cardiovascular outcomes. METHODS: Papers were identified from similar reviews published in 2013 and 2015, from the systematic reviews supporting the WHO 2018 noise guidelines, and from a literature search covering the period 2016-2022 using Medline and PubMed databases. Additional papers were identified from colleagues. Study selection was according to PECO inclusion criteria. Studies were evaluated against the WHO checklist for risk of bias. RESULTS: 52 publications, 36 published after 2015, were identified that assessed associations between transportation noise and cardiovascular outcomes, that also considered potential confounding (49 studies) or interaction (23 studies) by air pollution. Most, but not all studies, suggested that the associations between traffic noise and cardiovascular outcomes are independent of air pollution. NO2 or PM2.5 were the most commonly included air pollutants and we observed no clear differences across air pollutants in terms of the potential confounding role. Most papers did not appear to suggest an interaction between noise and air pollution. Eight studies found the largest noise effect estimates occurring within the higher noise and air pollution exposure categories, but were not often statistically significant. CONCLUSION: Whilst air pollution does not appear to confound associations of noise and cardiovascular health, more studies on potential interactions are needed. Current methods to assess quality of evidence are not optimal when evaluating evidence on confounding or interaction.

Mortality attributable to ambient fine particulate matter and nitrogen dioxide in Switzerland in 2019: Use of two-pollutant effect estimates.

INTRODUCTION: Air pollution health risk assessments have traditionally used single-pollutant effect estimates for one proxy ambient air pollutant such as PM2.5. Two-pollutant effect estimates, i.e. adjusted for another correlated pollutant, theoretically enable the aggregation of pollutant-specific health effects minimizing double-counting. Our study aimed at estimating the adult mortality in Switzerland in 2019 attributable to PM2.5 from a single-pollutant effect estimate and to the sum of PM2.5 and NO2 from two-pollutant estimates; comparing the results with those from alternative global, European and Swiss effect estimates. METHODS: For the single-pollutant approach, we used a PM2.5 summary estimate of European cohorts from the project ELAPSE, recommended by the European Respiratory Society and International Society for Environmental Epidemiology (ERS-ISEE). To derive the two-pollutant effect estimates, we applied ELAPSE-based conversion factors to ERS-ISEE PM2.5 and NO2 single-pollutant effect estimates. Additionally, we used World Health Organization 2021 Air Quality Guidelines as counterfactual scenario, exposure model data from 2019 and Swiss lifetables. RESULTS: The single-pollutant effect estimate for PM2.5 (1.118 [1.060; 1.179] per 10 µg/m3) resulted in 2240 deaths (21,593 years of life lost). Using our derived two-pollutant effect estimates (1.023 [1.012; 1.035] per 10 µg/m3 PM2.5 adjusted for NO2 and 1.040 [1.023; 1.058] per 10 µg/m3 NO2 adjusted for PM2.5), we found 1977 deaths (19,071 years of life lost) attributable to PM2.5 and NO2 together (23% from PM2.5). Deaths using alternative effect estimates ranged from 1042 to 5059. DISCUSSION: Estimated premature mortality attributable to PM2.5 alone was higher than to both PM2.5 and NO2 combined. Furthermore, the proportion of deaths from PM2.5 was lower than from NO2 in the two-pollutant approach. These seemingly paradoxical results, also found in some alternative estimates, are due to statistical imprecisions of underlying correction methods. Therefore, using two-pollutant effect estimates can lead to interpretation challenges in terms of causality.

An extra-chelator-free fenton process assisted by electrocatalytic-induced in-situ pollutant carboxylation for target refractory organic efficient treatment in chemical-industrial wastewater.

For traditional Fenton processes, the quenching behavior of radical contenders (e.g., most aliphatic hydrocarbons) on hydroxyl radicals (·OH) usually hinders the removal of target refractory pollutants (aromatic/heterocyclic hydrocarbons) in chemical industrial wastewater, leading to excess energy consumption. Herein, we proposed an electrocatalytic-assisted chelation-Fenton (EACF) process, with no extra-chelator addition, to significantly enhance target refractory pollutant (pyrazole as a representative) removal under high ·OH contender (glyoxal) levels. Experiments and theoretical calculations proved that superoxide radical (·O2-) and anodic direct electron transfer (DET) effectively converted the strong ·OH-quenching substance (glyoxal) to a weak radical competitor (oxalate) during the electrocatalytic oxidation process, promoting Fe2+ chelation and therefore increasing radical utilization for pyrazole degradation (reached maximum of ∼43-fold value upon traditional Fenton), which appeared more obviously in neutral/alkaline Fenton conditions. For actual pharmaceutical tailwater treatment, the EACF achieved 2-folds higher oriented-oxidation capability and ∼78% lower operation cost per pyrazole removal than the traditional Fenton process, demonstrating promising potential for future practical applications.

A comprehensive review on the potential of microbial enzymes in multipollutant bioremediation: Mechanisms, challenges, and future prospects.

Industrialization and other human activity represent significant environmental hazards. Toxic contaminants can harm a comprehensive platform of living organisms in their particular environments. Bioremediation is an effective remediation process in which harmful pollutants are eliminated from the environment using microorganisms or their enzymes. Microorganisms in the environment often create a variety of enzymes that can eliminate hazardous contaminants by using them as a substrate for development and growth. Through their catalytic reaction mechanism, microbial enzymes may degrade and eliminate harmful environmental pollutants and transform them into non-toxic forms. The principal types of microbial enzymes which can degrade most hazardous environmental contaminants include hydrolases, lipases, oxidoreductases, oxygenases, and laccases. Several immobilizations, genetic engineering strategies, and nanotechnology applications have been developed to improve enzyme performance and reduce pollution removal process costs. Until now, the practically applicable microbial enzymes from various microbial sources and their ability to degrade multipollutant effectively or transformation potential and mechanisms are unknown. Hence, more research and further studies are required. Additionally, there is a gap in the suitable approaches considering toxic multipollutants bioremediation using enzymatic applications. This review focused on the enzymatic elimination of harmful contaminants in the environment, such as dyes, polyaromatic hydrocarbons, plastics, heavy metals, and pesticides. Recent trends and future growth for effectively removing harmful contaminants by enzymatic degradation are also thoroughly discussed.

Advances in air pollution control for key industries in China during the 13th five-year plan.

Industrial development is an essential foundation of the national economy, but the industry is also the largest source of air pollution, of which power plants, iron and steel, building materials, and other industries emit large amounts of pollutants. Therefore, the Chinese government has promulgated a series of stringent emission regulations, and it is against this backdrop that research into air pollution control technologies for key industrial sectors is in full swing. In particular, during the 13th Five-Year Plan, breakthroughs have been made in pollution control technology for key industrial sectors. A multi-pollutant treatment technology system of desulfurization, denitrification, and dust collection, which applies to key industries such as power plants, steel, and building materials, has been developed. High-performance materials for the treatment of different pollutants, such as denitrification catalysts and desulfurization absorbers, were developed. At the same time, multi-pollutant synergistic removal technologies for flue gas in various industries have also become a hot research topic, with important breakthroughs in the synergistic removal of NOx, SOx, and Hg. Due to the increasingly stringent emission standards and regulations in China, there is still a need to work on the development of multi-pollutant synergistic technologies and further research and development of synergistic abatement technologies for CO2 to meet the requirements of ultra-low emissions in industrial sectors.

Bayesian kernel machine regression-causal mediation analysis.

Greater understanding of the pathways through which an environmental mixture operates is important to design effective interventions. We present new methodology to estimate natural direct and indirect effects and controlled direct effects of a complex mixture exposure on an outcome through a mediator variable. We implement Bayesian Kernel Machine Regression (BKMR) to allow for all possible interactions and nonlinear effects of (1) the co-exposures on the mediator, (2) the co-exposures and mediator on the outcome, and (3) selected covariates on the mediator and/or outcome. From the posterior predictive distributions of the mediator and outcome, we simulate counterfactuals to obtain posterior samples, estimates, and credible intervals of the mediation effects. Our simulation study demonstrates that when the exposure-mediator and exposure-mediator-outcome relationships are complex, BKMR-Causal Mediation Analysis performs better than current mediation methods. We applied our methodology to quantify the contribution of birth length as a mediator between in utero co-exposure to arsenic, manganese, and lead, and children's neurodevelopmental scores, in a prospective birth cohort in Bangladesh. Among younger children, we found a negative (adverse) association between the metal mixture and neurodevelopment. We also found evidence that birth length mediates the effect of exposure to the metal mixture on neurodevelopment for younger children. If birth length were fixed to its 75th percentile value, the harmful effect of the metal mixture on neurodevelopment is attenuated, suggesting nutritional interventions to help increase fetal growth, and thus birth length, could potentially block the harmful effect of the metal mixture on neurodevelopment.

The Unique CO Activation Effects for Boosting NH3 Selective Catalytic Oxidation over CuOx-CeO2.

Slip NH3 is a priority pollutant of concern to be removed in various flue gases with NOx and CO after denitrification using NH3-SCR or NH3-SNCR, and the simultaneous catalytic removal of NH3 and CO has become one of the new topics in the deep treatment of such flue gases. Synergistic catalytic oxidation of CO and NH3 appears to be a promising method but still has many challenges. Due to the competition for active oxidizing species, CO was supposed to hinder the NH3 selective catalytic oxidation (NH3-SCO). However, it is first found that CO could significantly promote NH3-SCO over the CuOx-CeO2 catalyst. The NH3 conversion rates increased linearly with CO concentrations in the range of 180-300 °C. Specifically, it accelerated by 2.8 times with 10,000 ppm CO inflow at 220 °C. Mechanism studies found that the Cu-O-Ce solid solution was more active for CO oxidation, while the CuOx species facilitated the NH3 dehydrogenation and mitigated the competition of NH3 and CO, further stabilizing the promotion effects. Gaseous CO boosted the generation of active isolated oxygen atoms (Oi) by actuating the Cu+/Cu2+ redox cycle. The enriched Oi facilitated oxidation of NH3 to NO and was conducive to the NH3-SCO via the i-SCR approach. This study tapped the potential of CO for promoting simultaneous catalytic oxidation of coexisting pollutants in the flue gas.

Structure-Directing Role of Support on Hg0 Oxidation over V2O5/TiO2 Catalyst Revealed for NOx and Hg0 Simultaneous Control in an SCR Reactor.

The crystal structure of TiO2 strongly influences the physiochemical properties of supported active sites and thus the catalytic performance of the as-synthesized catalyst. Herein, we synthesized TiO2 with different crystal forms (R = rutile, A = anatase, and B = brookite), which were used as supports to prepare vanadium-based catalysts for Hg0 oxidation. The Hg0 oxidation efficiency over V2O5/TiO2-B was the best, followed by V2O5/TiO2-A and V2O5/TiO2-R. Further experimental and theoretical results indicate that gaseous Hg0 reacts with surface-active chlorine species produced by the adsorbed HCl and the reaction orders of Hg0 oxidation over V2O5/TiO2 catalyst with respect to HCl and Hg0 concentration were approximately 0 and 1, respectively. The excellent Hg0 oxidation efficiency over V2O5/TiO2-B can be attributed to lower redox temperature, larger HCl adsorption capacity, and more oxygen vacancies. This work suggests that to achieve the best simultaneous removal of NOx and Hg0 on state-of-the-art V2O5/TiO2 catalyst, a combination of anatase and brookite TiO2-supported vanadyl tandem catalysts is supposed to be employed in the SCR reactor, and the brookite-type catalyst should be on the downstream of the anatase-based catalyst due to the inhibition of NH3 on Hg0 oxidation.

Interaction Mechanism for Simultaneous Elimination of Nitrogen Oxides and Toluene over the Bifunctional CeO2-TiO2 Mixed Oxide Catalyst.

Simultaneous catalytic elimination of nitrogen oxides (NOx, x = 1 and 2) and volatile organic compounds (VOCs) is of great importance for environmental preservation in China. In this work, the interactions of simultaneous removal of NOx and methylbenzene (PhCH3) were investigated on a CeO2-TiO2 mixed oxide catalyst, which demonstrated excellent bifunctional removal efficiencies for the two pollutants. The results indicated that NOx positively promotes PhCH3 oxidation, while NH3 negatively inhibits through competitive adsorption with PhCH3. The underlying mechanism is that a pseudo PhCH3-SCR reaction happened in this process is parallel to NH3-SCR. Combined with in situ diffuse reflectance infrared Fourier transform spectroscopy and quasi in situ X-ray photoelectron spectroscopy, the interaction mechanism between NOx and PhCH3 is proposed. Specifically, NOx is adsorbed on the catalyst surface to produce nitrate species, which reacts with the carboxylate generated during PhCH3 oxidation to form organic nitrogen intermediates that create N2 and CO2 in the following reactions. In the reaction process, the superoxide (O2-) generated by O2 activation on the catalyst surface is an important species for the propelling of oxidation reaction. This work could provide guidelines for the design of state-of-the-art catalysts for simultaneous catalytic removal of NOx and VOCs.

Improved morbidity-based air quality health index development using Bayesian multi-pollutant weighted model.

BACKGROUND: The widely used Air Quality Index (AQI) has been criticized due to its inaccuracy, leading to the development of the air quality health index (AQHI), an improvement on the AQI. However, there is currently no consensus on the most appropriate construction strategy for the AQHI. OBJECTIVES: In this study, we aimed to evaluate the utility of AQHIs constructed by different models and health outcomes, and determine a better strategy. METHODS: Based on the daily time-series outpatient visits and hospital admissions from 299 hospitals (January 2016-December 2018), and mortality (January 2017-December 2019) in Guangzhou, China, we utilized cumulative risk index (CRI) method, Bayesian multi-pollutant weighted (BMW) model and standard method to construct AQHIs for different health outcomes. The effectiveness of AQHIs constructed by different strategies was evaluated by a two-stage validation analysis and examined their exposure-response relationships with the cause-specific morbidity and mortality. RESULTS: Validation by different models showed that AQHI constructed with the BMW model (BMW-AQHI) had the strongest association with the health outcome either in the total population or subpopulation among air quality indexes, followed by AQHI constructed with the CRI method (CRI-AQHI), then common AQHI and AQI. Further validation by different health outcomes showed that AQHI constructed with the risk of outpatient visits generally exhibited the highest utility in presenting mortality and morbidity, followed by AQHI constructed with the risk of hospitalizations, then mortality-based AQHI and AQI. The contributions of NO2 and O3 to the final AQHI were prominent, while the contribution of SO2 and PM2.5 were relatively small. CONCLUSIONS: The BMW model is likely to be more effective for AQHI construction than CRI and standard methods. Based on the BMW model, the AQHI constructed with the outpatient data may be more effective in presenting short-term health risks associated with the co-exposure to air pollutants than the mortality-based AQHI and existing AQIs.

The establishment of Air Quality Health Index in China: A comparative analysis of methodological approaches.

BACKGROUND: The Air Quality Index (AQI) has been criticized because it does not adequately account for the health effect of multi-pollutants. Although the developed Air Quality Health Index (AQHI) is a more effective communication tool, little is known about the best method to construct AQHI on long time and large spatial scales. OBJECTIVES: To further evaluate the validity of existing approaches to the establishment of AQHI on both long time and larger spatial scales. METHODS: By introducing 3 approaches addressing multi-pollutant exposures: cumulative risk index (CRI), supervised principal component analysis (SPCA), and Bayesian multi-pollutants weighted model (BMP), we constructed CRI-AQHI, SPCA-AQHI, BMP-AQHI and standard-AQHI on cardiovascular mortality in China from 2015 to 2019 at both the national and geographic regional levels. We further assessed the performance of the four methods in estimating the joint effect of multi-pollutants by simulations under various scenarios of pollution effect. RESULTS: The results of national China showed that the BMP-AQHI improved the goodness of fit of the standard-AQHI by 108.24%, followed by CRI-AQHI (5.02%), and all AQHIs performed better than AQI, consistent with 6 geographic regional results. In addition, the simulation result showed that the BMP method provided stable and relatively accurate estimations of the short-term combined effect of exposure to multi-pollutants. CONCLUSIONS: AQHI based on BMP could communicate the air pollution risk to the public more effectively than the current AQHI and AQI.

Automated classification of time-activity-location patterns for improved estimation of personal exposure to air pollution.

BACKGROUND: Air pollution epidemiology has primarily relied on measurements from fixed outdoor air quality monitoring stations to derive population-scale exposure. Characterisation of individual time-activity-location patterns is critical for accurate estimations of personal exposure and dose because pollutant concentrations and inhalation rates vary significantly by location and activity. METHODS: We developed and evaluated an automated model to classify major exposure-related microenvironments (home, work, other static, in-transit) and separated them into indoor and outdoor locations, sleeping activity and five modes of transport (walking, cycling, car, bus, metro/train) with multidisciplinary methods from the fields of movement ecology and artificial intelligence. As input parameters, we used GPS coordinates, accelerometry, and noise, collected at 1 min intervals with a validated Personal Air quality Monitor (PAM) carried by 35 volunteers for one week each. The model classifications were then evaluated against manual time-activity logs kept by participants. RESULTS: Overall, the model performed reliably in classifying home, work, and other indoor microenvironments (F1-score>0.70) but only moderately well for sleeping and visits to outdoor microenvironments (F1-score=0.57 and 0.3 respectively). Random forest approaches performed very well in classifying modes of transport (F1-score>0.91). We found that the performance of the automated methods significantly surpassed those of manual logs. CONCLUSIONS: Automated models for time-activity classification can markedly improve exposure metrics. Such models can be developed in many programming languages, and if well formulated can have general applicability in large-scale health studies, providing a comprehensive picture of environmental health risks during daily life with readily gathered parameters from smartphone technologies.