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Nitrogen dioxide (NO 2) is a significant air pollutant with a notable environmental impact, necessitating precise monitoring. However, most existing NO 2 sensing materials exhibit low sensitivity and require high-temperature operation. In this study, we employed a hydrothermal and co-precipitation method to synthesize a novel ternary nanocomposite, In 2 O 3 /SnO 2 nanoparticles (NPs)/fluorine-doped carbon quantum dots (F-CDs). By varying the mass ratio of In 2 O 3 to SnO 2 NPs, we investigated the gas-sensing performance of the composite towards NO 2. The results demonstrate that when the ratio of SnO 2 and In 2 O 3 reaches to 1 : 2, the 2-In 2 O 3 /SnO 2 /F-CDs gas sensor exhibited the highest response, excellent selectivity, and remarkable stability under ultraviolet (UV) light irradiation at room temperature (∼25 °C). Furthermore, the response of the 2-In 2 O 3 /SnO 2 /F-CDs gas sensor displayed a strong linear relationship with the concentration of NO 2 gas. At a NO 2 gas concentration of 3 ppm, the sensitivity was 238, which is significantly higher than that of In 2 O 3 /SnO 2 NPs and In 2 O 3 sensors. The response time and recovery time were measured at 62 s and 33 s, respectively. Finally, based on experimental characterization results and band structure analysis, we confirmed the promising effects of ternary nanocomposite in enhancing gas sensing. [ABSTRACT FROM AUTHOR]

In this study, a hybrid model, the convolutional neural network-support vector regression model, was adopted to achieve prediction of the NO 2 profile in Nanjing from January 2019 to March 2021. Given the sudden decline in NO 2 in February 2020, the contribution of the Coronavirus Disease-19 (COVID-19) lockdown, Chinese New Year (CNY), and meteorological conditions to the reduction of NO 2 was evaluated. NO 2 vertical column densities (VCDs) from January to March 2020 decreased by 59.05% and 32.81%, relative to the same period in 2019 and 2021, respectively. During the period of 2020 COVID-19, the average NO 2 VCDs were 50.50% and 29.96% lower than those during the pre-lockdown and post-lockdown periods, respectively. The NO 2 volume mixing ratios (VMRs) during the 2020 COVID-19 lockdown significantly decreased below 400 m. The NO 2 VMRs under the different wind fields were significantly lower during the lockdown period than during the pre-lockdown period. This phenomenon could be attributed to the 2020 COVID-19 lockdown. The NO 2 VMRs before and after the CNY were significantly lower in 2020 than in 2019 and 2021 in the same period, which further proves that the decrease in NO 2 in February 2020 was attributed to the COVID-19 lockdown. Pollution source analysis of an NO 2 pollution episode during the lockdown period showed that the polluted air mass in the Beijing-Tianjin-Hebei was transported southwards under the action of the north wind, and the subsequent unfavorable meteorological conditions (local wind speed of < 2.0 m/sec) resulted in the accumulation of pollutants. [ABSTRACT FROM AUTHOR]

Ammonia have been attractive as one of the alternative fuels for reducing greenhouse gas (GHG) emissions. However, ammonia combustion has lower combustion performance than common hydrocarbon fuels. Furthermore, it may emit nitrous oxide (N 2 O), which is one of the GHGs. This paper presents the experimental investigations of plasma-assisted ammonia combustion (PAAC) using a rod-electrode-type microwave plasma source (MPS) at atmospheric pressure. The equivalence ratios of premixed ammonia/dry air (NH 3 /Air) gas are set below the stoichiometric combustion of NH 3 to reduce toxic NH 3 in the combustion gas. Under the condition of the equivalence ratios, the experiments are focused on reducing the unburned NH 3 and produced N 2 O concentrations in the combustion gas. In the experiments, the unburned NH 3 , nitrogen oxide (NO x) (the sum of nitric oxide (NO) and nitrogen dioxide (NO 2)), and N 2 O concentrations in the combustion gas are investigated in terms of the flow velocity of premixed NH 3 /Air gas inside the rod-electrode-type MPS and the transmission power to the rod-electrode-type MPS. In conclusion, the rod-electrode-type MPS is identified to be useful for PAAC. The NH 3 and N 2 O concentrations in the combustion gas reach approximately 25 and 4 parts per million (ppm), respectively, under the conditions of the equivalence ratio of 1.0, flow velocity of approximately 0.167 m/s, and transmission power of about 84 W. At that time, the NO x concentration is approximately 4300 ppm, and the power transmission efficiency is approximately 68 %. • Plasma-assisted ammonia combustion (PAAC) was conducted using microwave discharge. • The microwave discharge was generated using a rod-electrode-type microwave plasma source (MPS). • The experiments were conducted without a swirler and below the stoichiometric combustion. • The minimum concentrations of NH 3 and N 2 O in the combustion gas reached 25 and 4 ppm. • The rod-electrode-type MPS was identified to be useful for PAAC. [ABSTRACT FROM AUTHOR]

Nitrogen dioxide (NO 2) exposure can have several adverse health impacts on people, especially the respiratory system. Low selectivity, a lack of long-term stability, and structural and morphological optimization are some challenges associated with using ZnO for NO 2 gas sensing. Therefore, we intended copper (Cu) doping in ZnO to alter its shape and gas-sensing characteristics. This study explores the synthesis, properties, and gas-sensing capabilities of bitter gourd-shaped Cu-doped zinc oxide (ZnO) nanostructures for the detection of nitrogen dioxide (NO 2). A facile hydrothermal synthesis method was employed to synthesize bitter gourd-shaped Cu-doped ZnO nanostructures and comprehensively characterized by several techniques. Comprehensive characterizations of our produced Cu-doped ZnO nanomaterial demonstrated by X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDS), and different energy spectrum. The material was annealed at 400 °C in a controlled dry air environment to improve its suitability for gas sensor applications. A series of temperature-ranging experiments were conducted to get gas-sensing readings from 25 °C to 300 °C. The resulting sensor, founded upon the distinctive morphology of Cu-doped ZnO structures reminiscent of the intricate shape of bitter gourd, unveiled good selectivity with a pronounced affinity for detecting NO 2 gas. Notably, the zenith of its performance was attained at an operating temperature of 200 °C, where its selectivity and sensitivity were most pronounced. Even at a low concentration of 1 ppm, the sensors displayed a maximum response of 3.7, highlighting their high sensitivity. The sensors demonstrated excellent reproducibility, selectivity, and a low detection limit. These findings position bitter gourd-shaped Cu-doped ZnO nanostructures as promising candidates for NO 2 sensing applications across diverse environments. [ABSTRACT FROM AUTHOR]

The long-term feasibility and efficiency of microbial electrolysis cells (MECs) depend primarily upon several crucial parameters. However, they show promise for sustainably producing biohydrogen (bioH 2). This study investigates a newly designed biohydrogen reactor by studying the effects of several variables on the production of bioH 2 , including applied voltage, electrode material, and gas sparging with CO 2 and N 2. The study aims to optimize the system for improved efficiency and production performance. The results of this study show that both electrode type and applied voltage affect bioH 2 production where choosing the right inoculum has a significant impact on the catalytic efficiency. The aluminum electrodes significantly help produce the most bioH 2 production at 2.0 V with 884 mL/L in 11.25 min, while emphasizing the significance of material characteristics. The reduced partial pressure from CO 2 sparging, up to a point, improves bioH 2 generation. The N 2 gas sparging further demonstrates an increased efficiency where the ideal flow rates are dependent on the size of the MEC system. The highest bioH 2 production rates for CO 2 and N 2 sparging are measured as 821 mL/L and 813 mL/L in 4.25 min and 11.50 min at a volume of 400 mL/min and 300 mL/min, respectively. The results of this study further advance our knowledge of and ability to optimize MEC systems for long-term, sustainable bioH 2 production. [Display omitted] • A maximum hydrogen production of 892 mL is observed by microbial electrolysis cells. • Hydrogen production is improved in the presence of carbon dioxide and nitrogen gases. • Aluminum electrodes provide the highest hydrogen production at improved conditions. • The carbon dioxide input enhances the performance by six times considering time. • Maximum hydrogen production of 884 mL is achieved at a flow of 100 mL-N 2 /min. [ABSTRACT FROM AUTHOR]

Joint impacts of air pollution and physical activity (PA) on sleep quality remain unaddressed. We aimed to investigate whether PA attenuates the association of long-term exposure to nitrogen dioxide (NO 2) with sleep quality and its dimensions in older adults. This study included 3408 Chinese rural older adults. Annual NO 2 was estimated using the Space-Time Extra-Trees model. PA was assessed by International Physical Activity Questionnaire. Sleep quality was evaluated using Pittsburgh Sleep Quality Index (PSQI) scale. Linear regression models were used to assess the associations of long-term NO 2 exposure and PA with sleep quality and its dimensions, and interaction plots were used to depict the attenuating effect of PA on associations of NO 2 with sleep quality and its dimensions. Three-year (3-y) average NO 2 (per 0.64-μg/m3 increment) was positively associated with global PSQI (β = 0.41, 95 % CI : 0.23, 0.59), sleep duration (β = 0.16, 95 % CI : 0.11, 0.21), and habitual sleep efficiency (β = 0.22, 95 % CI : 0.17, 0.27), while PA was negatively associated with global PSQI (β = −0.33, 95 % CI : −0.46, −0.20) and five domains of PSQI other than sleep duration and sleep disturbances. The associations of NO 2 with global PSQI, sleep duration, and habitual sleep efficiency were attenuated with increased PA (P interaction were 0.037, 0.020, and 0.079, respectively). PA attenuates the adverse impacts of long-term NO 2 exposure on sleep quality, especially on sleep duration, and habitual sleep efficiency, in Chinese rural elderly people. Participating in PA should be encouraged in this population, and continued efforts are still needed to reduce air pollution. [Display omitted] • Long-term NO 2 exposure was positively associated with global PSQI, sleep duration, and habitual sleep efficiency. • PA was negatively associated with global PSQI and five domains of PSQI. • PA attenuates links between NO 2 exposure and global PSQI, sleep duration, and habitual sleep efficiency. [ABSTRACT FROM AUTHOR]

• NO 2 predictions of all monitoring stations in China were realized for 1-hr, 3-hr and 24-hr. • The ensemble model achieves excellent performance by incorporating deep learning. • Spatiotemporal covariates and multi-models reduce the spatial uncertainty of results. • Predictions are influenced by distinctive factors for different temporal resolutions. Nitrogen dioxide (NO 2) poses a critical potential risk to environmental quality and public health. A reliable machine learning (ML) forecasting framework will be useful to provide valuable information to support government decision-making. Based on the data from 1609 air quality monitors across China from 2014-2020, this study designed an ensemble ML model by integrating multiple types of spatial-temporal variables and three sub-models for time-sensitive prediction over a wide range. The ensemble ML model incorporates a residual connection to the gated recurrent unit (GRU) network and adopts the advantage of Transformer, extreme gradient boosting (XGBoost) and GRU with residual connection network, resulting in a 4.1%±1.0% lower root mean square error over XGBoost for the test results. The ensemble model shows great prediction performance, with coefficient of determination of 0.91, 0.86, and 0.77 for 1-hr, 3-hr, and 24-hr averages for the test results, respectively. In particular, this model has achieved excellent performance with low spatial uncertainty in Central, East, and North China, the major site-dense zones. Through the interpretability analysis based on the Shapley value for different temporal resolutions, we found that the contribution of atmospheric chemical processes is more important for hourly predictions compared with the daily scale predictions, while the impact of meteorological conditions would be ever-prominent for the latter. Compared with existing models for different spatiotemporal scales, the present model can be implemented at any air quality monitoring station across China to facilitate achieving rapid and dependable forecast of NO 2 , which will help developing effective control policies. [ABSTRACT FROM AUTHOR]

Due to the non-linearity in ozone (O 3) formation, reducing the emission of nitrogen oxides (NO x) may increase O 3 concentration. Given the counteractive O 3 response to NO x reduction, overall impact of air pollution controls can be ambiguous when the assessments focus on the changes in pollutant concentrations. In this study, a risk-based method was used to gauge the net effect of air pollution controls on mortality risk in the Beijing–Tianjin–Hebei (BTH) region during the 2022 Winter Olympics and Paralympics (WOP). This mega-event presents a unique opportunity to investigate the efficacy of deep cuts in pollutant emissions. Results show that O 3 concentrations greatly increased as nitrogen dioxide (NO 2) concentrations decreased in the BTH. Due to the active photochemical formations, O 3 became the dominant pollutant that affected human health during the WOP. Despite the substantial O 3 increases, the health benefits of NO 2 reductions overwhelmed the adverse health effects of O 3 increases in most regions of the BTH (at 81 out of 112 stations). After considering the impacts of particulate matter, the integrated health risk of air pollution mixtures declined almost everywhere in the BTH. Our results underscore the great necessity of changing the assessment paradigm of pollution control from using concentration-based methods to using risk-based methods. Together with the carbon neutrality policy, stringent control of NO x emission from combustion sources is a promising way to achieve synergistic control solutions for air pollution and climate change. [ABSTRACT FROM AUTHOR]

Emissions from road traffic, power generation and industry were substantially reduced during pandemic lockdown periods globally. Thus, we analysed reductions in traffic-related air pollution in Australian capital cities during March–April 2020 and then modelled the mortality benefits that could be realised if similar reductions were sustained by structural policy interventions. Satellite, air pollution monitor and land use observations were used to estimate ground-level nitrogen dioxide (NO 2) concentrations in all Australian capital cities during: (a) a typical year with no prolonged air pollution events; (b) a hypothetical sustained reduction in NO 2 equivalent to the COVID-19 lockdowns. We use the WHO recommended NO 2 exposure-response coefficient for mortality (1.023, 95 % CI: 1.008–1.037, per 10 μg/m3 annual average) to assess gains in life expectancy and population-wide years of life from reduced exposure to traffic-related air pollution. We attribute 1.1 % of deaths to anthropogenic NO 2 exposures in Australian cities, corresponding to a total of 13,340 years of life lost annually. Although COVID-19-related reductions in NO 2 varied widely between Australian cities during April 2020, equivalent and sustained reductions in NO 2 emissions could reduce NO 2 -attributable deaths by 27 %, resulting in 3348 years of life gained annually. COVID-19 mobility restrictions reduced NO 2 emissions and population-wide exposures in Australian cities. When sustained to the same extent by policy interventions that reduce fossil fuel consumption by favouring the uptake of electric vehicles, active travel and public transport, the health, mortality and economic benefits will be measurable in Australian cities. [Display omitted] [ABSTRACT FROM AUTHOR]

The photochemical nitrating agent 5-methyl-1,4-dinitro-1 H -imidazole (DNI) has been recently described as an effective tool for nitrating tyrosine residues in proteins under 390 nm irradiation (Long T. et al., 2021). Herein, we describe the one-step synthesis of DNI from the precursor 4-methyl-5-nitro-1 H -imidazole with good yield (66%) and high purity (>99%). Spectral analysis of DNI reveals two maximum peaks (228 and 290 nm) with maximum nitration yields and kinetics occurring at 290 nm. Electron paramagnetic resonance (EPR)- and mass spectrometry (MS)- spin trapping analysis evidenced the formation of nitrogen dioxide (•NO 2) upon irradiation of DNI, implying the homolysis of the N–N bond in the DNI molecule. Irradiation of DNI at 290, 390 nm, or UVA light (315–400 nm), produced tyrosine nitration, with yields approaching ca. 30% with respect to DNI at 290 nm exposure. Indeed, using alpha-synuclein as a model protein, the main protein post-translational modification triggered by DNI was the generation of 3-nitrotyrosine as shown by MS analysis. Additionally, the formation of di-tyrosine was also observed. Finally, intracellular •NO 2 production upon DNI photolysis in bovine aortic endothelial cells was evidenced by the nitration of the tyrosine analog probe p- hydroxyphenylacetic acid (PHPA) and cellular protein tyrosine nitration. [Display omitted] • DNI was synthetized by one-step conversion with high yield (66%) and purity (>99%). • DNI was characterized as photochemical •NO 2 donor upon irradiation. • The light source modulates •NO 2 fluxes varying nitration reaction yields and kinetics. • Nitration yields can reach up to ∼30% within 30 min at 290 nm irradiation. • Irradiation of DNI generates 3-NO 2 -Tyr in proteins in vitro and in cellula. [ABSTRACT FROM AUTHOR]

The lockdown policy deals a severe blow to the economy and greatly reduces the nitrogen oxides (NOx) emission in China when the coronavirus 2019 spreads widely in early 2020. Here we use satellite observations from Tropospheric Monitoring Instrument to study the year-round variation of the nitrogen dioxide (NO 2) tropospheric vertical column density (TVCD) in 2020. The NO 2 TVCD reveals a sharp drop, followed by small fluctuations and then a strong rebound when compared to 2019. By the end of 2020, the annual average NO 2 TVCD declines by only 3.4% in China mainland, much less than the reduction of 24.1% in the lockdown period. On the basis of quantitative analysis, we find the rebound of NO 2 TVCD is mainly caused by the rapid recovery of economy especially in the fourth quarter, when contribution of industry and power plant on NO 2 TVCD continues to rise. This revenge bounce of NO 2 indicates the emission reduction of NOx in lockdown period is basically offset by the recovery of economy, revealing the fact that China's economic development and NOx emissions are still not decoupled. More efforts are still required to stimulate low-pollution development. [ABSTRACT FROM AUTHOR]

We report a spatially resolved spectroscopic study of the visible chemiluminescence emission from different premixed ammonia-air-oxygen flames stabilized on a laminar flat flame burner, with equivalence ratio ranging from 0.7 to 1.35 and an O 2 /N 2 ratio of 0.4. In the reaction zone of the observed flames, the visible emission was recognized to be the chemiluminescence of excited NH 2 * radicals, while in the post-flame zone, two types of chemiluminescence were observed: NO 2 * chemiluminescence dominated in the fuel-lean flames and NH 2 * chemiluminescence dominated in the fuel-rich flames. The high-resolution spectra of the NO 2 * and NH 2 * chemiluminescence in the visible region (400-700 nm) were recorded. The intensity of both spectra increased gradually with wavelength. However, the NO 2 *-chemiluminescence spectrum appeared to be continuous and unstructured, while the NH 2 *-chemiluminescence spectrum consisted of groups of distinct emission lines. Based on the spectral feature, the ratios of the integrated chemiluminescence intensities over the 598-603 nm wavelength range to the intensities over the 586-592 nm range and 447-453 nm range were used to sense equivalence ratio. In addition, slightly different colors of the fuel-lean and fuel-rich flames were observed, due to the fact that NO 2 * chemiluminescence had a relatively stronger signal in the blue region than NH 2 * chemiluminescence. The difference was used to infer flame equivalence ratio using the flame images recorded by a RGB digital camera, where the ratio of the signal from the red channel to the signal from the blue channel was calculated. [ABSTRACT FROM AUTHOR]

Liquefied petroleum gas (LPG) is a primary fuel in rural residence. LPG burning can generate detrimental air pollutants, e.g. formaldehyde (HCHO) and nitrogen dioxide (NO 2), posing health hazard to human beings and affecting atmospheric environment. However, emission characteristics of HCHO and NO 2 from LPG combustion remains unclear. To address this issue, this study investigated emission rate and emission factor of formaldehyde and NO 2 by field measurements in nine Chinese kitchens. Results showed that LPG combustion rate in this study varied in 185 mg/min - 4477 mg/min. Given this combustion rate, emission rates of formaldehyde and NO 2 ranged from 0.003 mg/min to 0.460 mg/min (median: 0.125 mg/min) and 0.004 mg/min to 0.746 mg/min (median: 0.139 mg/min), respectively. Accordingly, emission factor of formaldehyde and NO 2 were in a range of 1.65–1064 mg/kg (median: 151 mg/kg) and 1.84–611 mg/kg (median: 111 mg/kg), respectively. As LPG flow increased, emission factor of formaldehyde and NO 2 decreased significantly (p < 0.05). For typical use in residences, annual emissions of formaldehyde and NO 2 from household LPG combustion were estimated up to 3200 ± 2775 tons and 2400 ± 1953 tons in China, respectively. Formaldehyde and NO 2 dispersed quickly from kitchen to an adjacent living room when kitchen door was open. The range hood exhaust can substantially remove formaldehyde (decrease by 58%) and NO 2 (decrease by 57%) when window is open and kitchen door is closed. This study provides baseline information on pollutant emissions from LPG combustion along with CO 2 , and also reveals that building electrification can have both health and climate yields. [Display omitted] [ABSTRACT FROM AUTHOR]

• Impact of NO 2 and O 3 on SO 2 -SO 4 2− conversion is identified based on MFDCCA method. • NO 2 has stronger promoting effect on SO 2 -SO 4 2− conversion in winter than in summer. • The higher the efficiency of SO 2 -SO 4 2− conversion, the lower the O 3 level. • Reductions in SO 4 2−/NO 3 − ratio may make O 3 pollution more severe in Hong Kong. As an important component of secondary aerosols, sulfate plays a crucial role in regulating atmospheric radiative balance and influencing the secondary formation of ozone (O 3). In real atmosphere, atmospheric oxidants NO 2 and O 3 can promote the oxidation of SO 2 to form sulfate (SO 4 2−) through multiphase chemistry that occur at different time scales. Due to the combined impact of meteorology, pollution sources, atmospheric chemistry, etc., time-scale dependence of SO 2 -SO 4 2− conversion makes the impact of NO 2 /O 3 on it more complex. In this study, based on long-term time series (2013-2020) of air pollution variables from seven stations in Hong Kong, the Multifractal Detrended Cross-Correlation Analysis (MFDCCA) method has been employed to quantify the cross-correlations between SO 2 and SO 4 2− in real atmosphere at different time scales, for examining the time-scale dependence of SO 2 -SO 4 2− conversion efficiency. Furthermore, the Pearson correlation analysis has been used to study the influence of NO 2 /O 3 on SO 2 -SO 4 2− conversion, and the regional and seasonal differences have been analyzed by considering factors such as meteorology, pollution sources, and regional transport. Changes in the main components of secondary aerosols are closely linked with the co-control of regional PM 2.5 and O 3. Therefore, the exploration of the impact of co-existing NO 2 /O 3 gases on the secondary formation of sulfates in real atmosphere is significant. [Display omitted] [ABSTRACT FROM AUTHOR]

A growing body of evidence suggests that air pollution exposure is associated with an increased risk for cardiovascular diseases. Data regarding the impact of long-term air pollution exposure on ischemic stroke mortality are sparse. The German nationwide inpatient sample was used to analyse all cases of hospitalized patients with ischemic stroke in Germany 2015–2019, which were stratified according to their residency. Data of the German Federal Environmental Agency regarding average values of air pollutants were assessed from 2015 to 2019 at district-level. Data were combined and the impact of different air pollution parameters on in-hospital case-fatality was analyzed. Overall, 1,505,496 hospitalizations of patients with ischemic stroke (47.7% females; 67.4 % ≥70 years old) were counted in Germany 2015–2019, of whom 8.2 % died during hospitalization. When comparing patients with residency in federal districts with high vs. low long-term air pollution, enhanced levels of benzene (OR 1.082 [95%CI 1.034–1.132], P = 0.001), ozone (O 3, OR 1.123 [95%CI 1.070–1.178], P < 0.001), nitric oxide (NO, OR 1.076 [95%CI 1.027–1.127], P = 0.002) and PM 2.5 fine particulate matter concentrations (OR 1.126 [95%CI 1.074–1.180],P < 0.001) were significantly associated with increased case-fatality independent from age, sex, cardiovascular risk-factors, comorbidities, and revascularization treatments. Conversely, enhanced carbon monoxide, nitrogen dioxide, PM 10, and sulphur dioxide (SO 2) concentrations were not significantly associated with stroke mortality. However, SO 2 − concentrations were significantly associated with stroke-case-fatality rate of >8 % independent of residence area-type and area use (OR 1.518 [95%CI 1.012–2.278], P = 0.044). Elevated long-term air pollution levels in residential areas in Germany, notably of benzene, O 3 , NO, SO 2, and PM 2.5 , were associated with increased stroke mortality of patients. Evidence before this study: Besides typical, established risk factors, increasing evidence suggests that air pollution is an important and growing risk factor for stroke events, estimated to be responsible for approximately 14 % of all stroke-associated deaths. However, real-world data regarding the impact of long-term exposure to air pollution on stroke mortality are sparse. Added value of this study: The present study demonstrates that the long-term exposure to the air pollutants benzene, O 3 , NO, SO 2 and PM 2.5 are independently associated with increased case-fatality of hospitalized patients with ischemic stroke in Germany. Implications of all the available evidence: The results of our study support the urgent need to reduce the exposure to air pollution by tightening emission controls to reduce the stroke burden and stroke mortality. Panel A - In-hospital case-fatality rate of ischemic stroke patients residing in the different federal districts of Germany. Panel B - Impact of air pollution on increased stroke mortality. [Display omitted] • Air pollution is an important risk factor for stroke, but data regarding impact on mortality are sparse • Long-term exposure to the air pollutants benzene, O 3 , NO, SO 2 and PM 2.5 are associated with increased in-hospital case-fatality • Our study support the need to reduce air pollution exposures to reduce stroke burden and stroke mortality [ABSTRACT FROM AUTHOR]

Traditional air quality data have a spatial resolution of 1 km or above, making it challenging to resolve detailed air pollution exposure in complex urban areas. Combining urban morphology, dynamic traffic emission, regional and local meteorology, physicochemical transformations in air quality models using big data fusion technology, an ultra-fine resolution modeling system was developed to provide air quality data down to street level. Based on one-year ultra-fine resolution data, this study investigated the effects of pollution heterogeneity on the individual and population exposure to particulate matter (PM 2.5 and PM 10), nitrogen dioxide (NO 2), and ozone (O 3) in Hong Kong, one of the most densely populated and urbanized cities. Sharp fine-scale variabilities in air pollution were revealed within individual city blocks. Using traditional 1 km average to represent individual exposure resulted in a positively skewed deviation of up to 200% for high-end exposure individuals. Citizens were disproportionally affected by air pollution, with annual pollutant concentrations varied by factors of 2 to 5 among 452 District Council Constituency Areas (DCCAs) in Hong Kong, indicating great environmental inequities among the population. Unfavorable city planning resulted in a positive spatial coincidence between pollution and population, which increased public exposure to air pollutants by as large as 46% among districts in Hong Kong. Our results highlight the importance of ultra-fine pollutant data in quantifying the heterogeneity in pollution exposure in the dense urban area and the critical role of smart urban planning in reducing exposure inequities. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, tungsten oxide (WO 3) nanofibers were prepared using electrospinning technology and combined with La 0.8 Pb 0.2 FeO 3 (LPFO) perovskite materials to form a heterostructure film, and then used to evaluate the potential as a gas sensing material. The results show that the pure WO 3 nanofiber gas sensor has an excellent sensing effect on nitrogen dioxide (NO 2) and hydrogen sulfide (H 2 S), and the WO 3 /LPFO heterostructure film gas sensor still has a high response to H 2 S, but the response to NO 2 is suppressed. This WO 3 /LPFO heterostructure film gas sensor greatly improves the gas selectivity, making the selectivity more specific. The WO 3 /LPFO heterostructure film gas sensor exhibits excellent gas selectivity for H 2 S gas, the optimal operating temperature is 175 °C, and the response is about 89.5% under 1.25 ppm H 2 S gas. [ABSTRACT FROM AUTHOR]

Based on one-year observation, the concentration, sources, and potential source areas of volatile organic compounds (VOCs) were comprehensively analyzed to investigate the pollution characteristics of ambient VOCs in Haikou, China. The results showed that the annual average concentration of total VOCs (TVOCs) was 11.4 ppbV, and the composition was dominated by alkanes (8.2 ppbV, 71.4%) and alkenes (1.3 ppbV, 20.5%). The diurnal variation in the concentration of dominant VOC species showed a distinct bimodal distribution with peaks in the morning and evening. The greatest contribution to ozone formation potential (OFP) was made by alkenes (51.6%), followed by alkanes (27.2%). The concentrations of VOCs and nitrogen dioxide (NO 2) in spring and summer were low, and it was difficult to generate high ozone (O 3) concentrations through photochemical reactions. The significant increase in O 3 concentrations in autumn and winter was mainly related to the transmission of pollutants from the northeast. Traffic sources (40.1%), industrial sources (19.4%), combustion sources (18.6%), solvent usage sources (15.5%) and plant sources (6.4%) were identified as major sources of VOCs through the positive matrix factorization (PMF) model. The southeastern coastal areas of China were identified as major potential source areas of VOCs through the potential source contribution function (PSCF) and concentration-weighted trajectory (CWT) models. Overall, the concentration of ambient VOCs in Haikou was strongly influenced by traffic sources and long-distance transport, and the control of VOCs emitted from vehicles should be strengthened to reduce the active species of ambient VOCs in Haikou, thereby reducing the generation of O 3. [Display omitted]. [ABSTRACT FROM AUTHOR]

Over the past decades, particulate matter (PM), especially fine PM <2.5 μm in aerodynamic diameter (PM 2.5) has been a major research focus. However, the air pollutant is a mixture of gases or vapour-phase compounds, such as carbon monoxide (C), nitrogen oxides (NO x), photochemical oxidants (Ox), and sulfur dioxide (SO 2). Little is known about their cardiovascular effect, individually or in combination with PM. Thus, we aimed to determine the associations between the incidence of acute cardiac events and both gaseous and PM using a case-crossover design. Cardiovascular cases were identified through the Gunma Prefectural Ambulance Activity Database in Japan in 2015 (1,512 out-of-hospital cardiac arrest [OHCA] and 1,002 heart failures from 53,006 ambulance cases). Air quality data from the nearest station was for day of the arrest (lag0) and 1-2 days before the arrest (lag1, lag2) and the moving average across days 0-1 (lag0-1). Conditional logistic regression was used for unadjusted and adjusted analysis for temperature and humidity. Independent associations of OHCA were daily concentrations of SO 2 at lag1 (OR 1.173, 95%CI 1.004, 1.370; p=0.044) and lag0-1 (OR 1.203, 95%CI 1.015, 1.425; p=0.033); and daily NO concentrations at lag2 (OR 1.039, 95%CI 1.007, 1.072; p=0.016). The incidence of heart failure was significantly associated with daily concentrations of O x on the day of the event in univariable model but not after adjustment for temperature and humidity. No associations were found for other pollutants. Short-term exposure to SO 2 and NO are associated with an increased risk of OHCA. [ABSTRACT FROM AUTHOR]

Formaldehyde (HCHO) and glyoxal (CHOCHO) are important oxidization intermediates of most volatile organic compounds (VOCs), but their vertical evolution in urban areas is not well understood. Vertical profiles of HCHO, CHOCHO, and nitrogen dioxide (NO 2) were retrieved from ground-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) observations in Hefei, China. HCHO and CHOCHO vertical profiles prefer to occur at higher altitudes compared to NO 2 , which might be caused by the photochemistry-oxidation of longer-lived VOCs at higher altitudes. Monthly means of HCHO concentrations were higher in summer, while enhanced amounts of NO 2 were mainly observed in winter. CHOCHO exhibited a hump-like seasonal variation, with higher monthly-averaged values not only occurred in warm months (July-August) but also in cold months (November-December). Peak values mainly occurred during noon for HCHO but emerged in the morning for CHOCHO and NO 2 , suggesting that HCHO is stronger link to photochemistry than CHOCHO. We further use the glyoxal to formaldehyde ratio (GFR) to investigate the VOC sources at different altitudes. The lowest GFR value is almost found in the altitude from 0.2 to 0.4 km, and then rises rapidly as the altitude increases. The GFR results indicate that the largest contributor of the precursor VOC is biogenic VOCs at lower altitudes, while at higher altitudes is anthropogenic VOCs. Our findings provide a lot more insight into VOC sources at vertical direction, but more verification is recommended to be done in the future. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The Fe-Ni@WS 2 exhibits a remarkable performance for NO 2 at room temperature. • Bimetallic modification effectively regulates the charge conduction process of WS 2. • Electronic activation and chemical sensitization of Fe and Ni enhance the sensing performance of Fe-Ni@WS 2. Rapid and highly sensitive detection of toxic gases at room temperature is crucial for ensuring health protection. However, the sensing materials reported thus far face the challenge of exhibiting relatively low response values at room temperature. In this study, we propose a facile synthesis method to prepare a Fe and Ni co-doped WS 2 gas sensor capable of detecting nitrogen dioxide (NO 2) at parts-per-billion (ppb) levels even at room temperature. The Fe-Ni@WS 2 gas sensor exhibits excellent response performance (The response value is 81 at 1 ppm NO 2). The incorporation of Fe and Ni into WS 2 forms a Schottky junction that effectively regulates charge transfer behavior within the sensor material through conduction tunneling. Furthermore, the catalytic properties of Fe and Ni promote gas-sensitive reactions on the surface of WS 2. This investigation elucidates the sensing mechanism of WS 2 towards NO 2 under bimetallic modification and provides an effective approach for constructing high-performance gas sensors through rational design of active sites. [ABSTRACT FROM AUTHOR]

In diesel engines, nitrogen monoxide (NO) is the predominant component of nitrogen oxides (NOx) emissions. However, when transitioning to methanol/diesel dual-fuel operation, even with a small percentage of methanol replacing diesel energy (e.g. 10 %), the concentration of nitrogen dioxide (NO 2) increases significantly, becoming comparable to that of NO. This study employs multi-dimensional computational fluid dynamics (CFD) modeling to reproduce this NO 2 /NOx surge ratio phenomenon and investigates the underlying mechanism driving the surge in NO 2 emissions, an area insufficiently explored in existing literature. By comparing CFD simulations with and without the NO+HO 2 ↔NO 2 + OH reaction in the chemical mechanism, the results reveal that the surge in NO 2 concentration disappears when this reaction is invalidated, while engine efficiency, combustion phasing, and overall NOx emissions remain largely unchanged. This indicates that the NO+HO 2 ↔NO 2 + OH reaction is the primary contributor to the sudden increase in the NO 2 /NOx ratio. Further analysis during the main combustion stage shows that the diesel spray splits into two distinct regions after impinging on the bowl boundary, with one region deep within the bowl and the other near the squish region. During the late oxidation stage, the diffusion flame directed towards the deep bowl area remains a high-temperature zone with a high concentration of NO, whereas the flame near the squish region evolves into a low-temperature zone due to effective mixing with the low-temperature methanol/air mixture. In these low-temperature regions, almost all NO formed during the main combustion stage is converted to NO 2 during the late oxidation stage, leading to the observed NO 2 /NOx ratio surge. Methanol oxidation contributes HO 2 radicals, which facilitate the NO-to-NO 2 conversion. Consequently, the low-temperature oxidation of methanol outside the high-temperature region does not lead to thermal ignition but is instead responsible for the rare occurrence of the NO 2 surge. • Using methanol to partly diesel in engines dramatically increase NO 2 emissions. • 3D CFD modeling reproduces the surge in NO 2 /NOx ratio of methanol/diesel operation. • Disabling NO+HO 2 ↔NO 2 + OH eliminates the NO 2 concentration surge. • NO 2 surge occurs in low-temperature zones during late oxidation. • Low-temperature oxidation of methanol converts NO to NO 2. [ABSTRACT FROM AUTHOR]

Metal oxides are widely used because of their simple structure, low price, and excellent gas-sensitive properties. But now, the metal oxide sensor faces two challenges. One is that when the detection limit of the sensor is low, it will be affected by a high concentration of gas and fail in practical applications. Second, the metal oxide sensor is susceptible to temperature changes, resulting in inaccurate measurement results. To address the above problems, the performance of metal oxides is enhanced through doping. Indium oxide doped with various levels of indium molybdate was prepared using a two-step hydrothermal method resulting in a composite material with an n-n heterostructure. The interaction formed by the n-n heterostructure enhances the redox reaction between NO 2 gas and the sensor, and the unique nano cluster structure provides more active sites for the sensor, significantly improving the gas performance of the sensor towards NO 2. Sensors based on In 2 (MoO 4) 3 with a doping ratio of 4 % (the sample IM3) showed excellent gas sensitivity. The lower and upper detection limits of the sensor are 200 ppb (response is 1.46) and 150 ppm (response is 515.94), respectively. And the sensor has good resistance to ultra-high concentration (10000 ppm) nitrogen dioxide (NO 2) impact. In the range of 130–170°C, the temperature has a small and linear effect on the sensor response, which is very beneficial for temperature correction of gas sensors. The sensor prepared by In 2 (MoO 4) 3 doped In 2 O 3 composite material has a good potential for application in engineering practice. [Display omitted] • The IM3 sensor can resist the impact of 10000 ppm NO 2 and recover. • The response of IM3 sensor to 150 ppm is 515.49. • The temperature disturbance is linear to reduce its influence on the IM3 sensor. [ABSTRACT FROM AUTHOR]

Photo-activated chemiresistive sensors have introduced a considerable improvement among all gas sensor technologies. However, the major drawback of these gas sensors is the long response time, which limits the potential of such sensors in many applications where rapid measurement is required. In this work, we investigated the response curve slope for gas concentration measurement. Our aim was to significantly reduce the response time of the ultraviolet light-emitting diodes (UV-LED)-activated chemiresistive metal oxide semiconductor (MOS) gas sensors so that steady-state response times are no longer needed. As a model semiconductor, zinc oxide (ZnO) nanowires (NWs) were fabricated to detect different concentrations of nitrogen dioxide (NO 2) at room temperature under UV radiation with a wavelength of 275 nm. The consistent slope measurement results and the reproducible correlation between the response curve slope and the NO 2 concentration represented the slope as an indicator of the gas concentration. The results indicated relatively high steady-state responses of 0.36, 0.65, 1.15, and 1.51 to the 5, 10, 25, and 50 ppm concentrations of NO 2 , respectively. [Display omitted] • UV-LED-activated ZnO semiconductor is a promising gas-sensing material. • The initial response curve slope (IRCS) is a reliable indicator of the NO 2 concentration. • The IRCS indicates the changes in concentration in the presence of a background gas. [ABSTRACT FROM AUTHOR]

Noble metal loading is an efficient way to improve the sensing performance of metal oxide semiconductor (MOS) gas sensors. In this work, platinum (Pt) nanoclusters loaded ZnO nanowires (Pt c -ZnO) were used to fabricate a NO 2 sensor. Pure ZnO nanowires were prepared by a solvothermal method and Pt nanoclusters were loaded via a sacrificial templating route. The Pt c -ZnO based sensor with a trace of Pt loading (0.17 wt%) shows a high response to ppb-level NO 2 (26.1–100 ppb), 4.4 times higher than that of pure ZnO. Additionally, it also exhibits excellent selectivity, low theoretical limit of detection (1.19 ppb) and good stability to humidity. The enhancing mechanism on gas sensing performance by Pt loading was discussed and investigated via HAADF-STEM, XPS, NO 2 -TPD and other methods. This work provides a way to develop gas sensor for ultralow NO 2 concentration real-time detection. • Pt nanoclusters were loaded on the ZnO nanowires via N doped graphene (NG) sacrificial templating route. • Compared to pure ZnO, the Pt c -ZnO based sensor exhibits higher response and rapider response/recovery properties to NO 2. • The Pt c -ZnO based sensor exhibits excellent selectivity and reliable anti-humidity capability to NO 2. • Characterization methods such as HAADF-STEM, XPS and NO 2 -TPD were used to discuss the enhancing mechanism. [ABSTRACT FROM AUTHOR]

In a recent while, heterostructured nanomaterials have shown great potential for highly sensitive and selective gas sensing applications. Herein, CeO 2 –ZrO 2 nanocomposites were fabricated in varying compositions in lower CeO 2 region (2.5–10 %) via hydrothermal methodology. UV–visible DRS studies ascertained the band gap tailoring of the heterojunctions ranging from 3.33 to 4.07 eV as compared to their pure counter parts CeO 2 (3.03 eV) and ZrO 2 (4.96 eV). The surface area studies revealed the high specific surface areas of 90, 81.2, 72.7 and 61 m2/g for the 2.5, 5, 7.5 and 10 % CeO 2 –ZrO 2 hetero-nanocomposites along with 53.2 and 108 m2/g for pure CeO 2 and ZrO 2 nanostructures, respectively. CeO 2 –ZrO 2 nanocomposites revealed ameliorated sensing response towards the NO 2 as compared to the bare ZrO 2. The maximum sensitivity of 1572 was shown by the 5 % CeO 2 –ZrO 2 nanocomposite at optimum operating thermal conditions of 250 °C that was relatively higher as compared to pristine ZrO 2 nanospheres. Augmented sensing efficiency is attributed to the tweaked surface area of the nanocomposites, alleviated band energy, existence of oxygen vacant sites over CeO 2 surface and ameliorated interaction due to the formation of CeO 2 –ZrO 2 heterojunctions. The improved sensing performance of CeO 2 –ZrO 2 sensors has been extensively discussed alongside mechanistic sketch. [Display omitted] • 2.5–10 % CeO 2 /ZrO 2 p-n Heterojunctions by taking their monophasic NPs using hydrothermal approach. • 5 % CeO 2 -ZrO 2 nanoheterostructure displayed outstanding NO 2 sensing performance at 250 °C. • Higher sensing response is inferred to the existence of large amounts of oxygen vacancies on CeO 2 surface. • Synergistic interaction between CeO 2 and ZrO 2 interfaces due to enhanced surface area and low band gap. [ABSTRACT FROM AUTHOR]

This study presents a chemiresistive nitrogen dioxide (NO 2) sensor based on reduced graphene oxide (rGO) combined with 5, 10, 15, 20-Tetra-p-tolyl-21 H, 23 H-porphine (TPTP) and 5-(4-Methoxycarbonylphenyl)-10,15,20-triphenyl-21 H,23 H-porphine (MCPTPP). Structural, spectroscopic, morphological, and electrical characterizations of rGO/MCPTPP and rGO/TPTP/MCPTPP were carried out using X-ray diffraction, FTIR, AFM, SEM and current-voltage (I-V) respectively. The flexible ITO-coated electrodes were used to investigate sensing properties. The rGO/TPTP/MCPTPP-based sensor exhibited exceptional selectivity, sensitivity, and reproducibility toward NO 2 analytes detection. MCPTPP and TPTP enhanced sensor performance due to their unique interactions with NO 2. The rGO/TPTP/MCPTPP sensor exhibited remarkable linearity with a wide dynamic range of 400–100 ppm at (room temperature) RT and remained linear for low concentrations, specifically 35–1 ppm. The sensors also displayed excellent reproducibility over multiple sensing cycles. The superior performance of these sensors makes them promising candidates for various environmental monitoring and industrial applications requiring precise and reliable NO 2 detection. [Display omitted] • The study introduces an NO 2 sensor based on rGO combined with TPTP and MCPTPP porphyrins, which enhance its gas detection capabilities. • The sensor showed exceptional selectivity, sensitivity, and reproducibility for NO 2 detection due to unique interactions between porphyrins and NO 2. • It exhibited a linear response to NO 2 for 1–400 ppm at RT. • The sensor is ideal for environmental monitoring and industrial uses requiring precise and reliable NO 2 detection. [ABSTRACT FROM AUTHOR]

The GEOstationary Coastal and Air Pollution Events (GEO-CAPE) Airborne Simulator (GCAS) instrument made observations over the South Korea during Satellite Integrated Joint Monitoring for Air Quality (SIJAQ) 2022 (July–August 2022) campaign aimed at collecting high-resolution remote sensing data. To investigate the impact of spatial resolution on nitrogen dioxide (NO 2) retrieval from remote sensing data, the NO 2 differential slant column density (dSCD) was examined using high-resolution GCAS data, which are suitable for upscaling, to identify differences related to spatial resolution. Through the GCAS NO 2 dSCD, the structure at the original resolution (100 m × 200 m) was maintained even following a shift to a coarser resolution; however, it was difficult to distinguish boundary areas with large concentration differences at resolutions coarser than 1.5 km × 3 km. In the comparison of coadded NO 2 dSCD and merged NO 2 dSCD, the standard deviations from the merged data increased when NO 2 dSCD was >3 × 1016 molecules/cm2, such as in the high NO 2 concentration cases. The slope of the scatter plot obtained using the top 25% of the data determined from the regression line tended to increase as the resolution became coarser. In addition, the average standard deviation within merged pixels at a resolution of 3 km × 6 km was twice that obtained at 400 m × 800 m resolution. Accordingly, the standard deviation of the information contained in the pixels increased when the spatial resolution became coarser. • GCAS observation was established by 14 times aircraft flight during the SIJAQ 2022 campaign in South Korea. • High polluted NO2 concentration region has inconsistencies as changing the spatial resolution of pixels. • NO 2 dSCD from DOAS fitting is significantly affected by the spatial resolution of pixels. [ABSTRACT FROM AUTHOR]

• NO interconversion into NO 2 was measured using a laser gas analyzer. • Ignition delays of H 2 /air/NO x mixtures were measured at φ = 0.4, p C = 30 – 60 bar and T C = 890 – 1000 K. • Compression pressure and X NOx increases enhance the reactivity. • The proposed kinetic mechanism displays good agreement with the experiments. This study investigates the effects of nitric oxides addition on ignition delay times of lean hydrogen/air mixtures (φ = 0.4), in the 890 K – 1000 K temperature range and for medium-to-high compression pressures (p C = 30, 40, 50, and 60 bar). Results show that ignition delay times decrease with the addition of nitric oxide and nitrogen dioxide, regardless of the compression pressure. These datasets provide new insights to assess the validity of kinetic mechanisms under such conditions and predict autoignition phenomena. As such, a comparison with recent kinetic mechanisms is conducted. A sensitivity analysis on OH radical is performed and highlights the role of the HO 2 /H 2 O 2 and NO/NO 2 recycling sequences in OH production, yielding an increase in the mixture reactivity. Finally, this work highlighted the importance weight of (R17) in reactivity enhancement and gave a perspective to optimize NO x sub-mechanisms for hydrogen ignition under internal combustion engine conditions. [ABSTRACT FROM AUTHOR]

Nitrogen dioxide (NO 2) sensors experience the drawback of requiring high operating temperatures because of the low charge transfer ability of gas-sensing materials. Herein, an advanced NO 2 sensor resistant to interference is designed using the interfacial energy barriers of a hierarchical CuO/ZnO composite. With the benefits of abundant desirable defect features, and the amplification effect of heterojunctions, the sensor based on CuO/ZnO composite with 10% Cu(CH 3 COO) 2 ·H 2 O (S2) shows outstanding performance in terms of faster response and recovery time (1.8-fold/1.1-fold), higher response (3.1-fold), and lower power consumption (140℃ decrease) compared to the pristine ZnO sensor. Furthermore, the composite sensor exhibits long-term stability and reproducibility, indicating the potential promise of CuO/ZnO heterojunctions in interference-resistant detection of low-concentration NO 2 in real applications. This study not only provides a rational solution to designing advanced gas sensors by tuning the interfacial energy barriers of heterojunctions, but also provides a fundamental understanding of CuO structures in the gas-sensing field. • CuO/ZnO nano-materials are synthesized by a hydrothermal method. • The doping of CuO increases the absorbed site of ZnO nano-material. • Heterostructure and microspheres structure jointly promote the sensing performance. • Sensing mechanism and structural merits of hierarchical nanostructure are advanced. [ABSTRACT FROM AUTHOR]

Metal vanadates are attracting an increasing interest as photocatalysts, photovoltaics, electrolytes and sensors. Mixed-metal oxide semiconductors are promising materials for gas sensors. Indium vanadate InVO 4 is derivative from indium and vanadium(V) oxides, which are well known sensing materials. However, the sensing behavior, active sites and sensing mechanism of InVO 4 were not studied. In this work, InVO 4 nanoparticles are synthesized hydrothermally, and In 2 O 3 and V 2 O 5 are obtained as reference materials. Surface acidity and surface oxygen species are determined by temperature-programmed techniques with probe molecules, XPS and FTIR. Gas sensitivity of the materials to noxious inorganic and volatile organic compounds is investigated. InVO 4 demonstrates superior sensitivity to NO 2 at moderate temperature 150 °C with good stability at 0–60 % relative humidity (at 27 °C). Using in situ infrared (DRIFT) spectroscopy, it is shown that NO 2 was adsorbed on InVO 4 in different forms, including nitrosyl species. It enables deep NO 2 reduction at the surface of InVO 4 , in addition to the reaction of nitrates and nitrites formation observed on In 2 O 3. Based on the results of temperature programmed reduction, the origin of higher surface reactivity and sensitivity to NO 2 is deduced to be a larger number of oxygen vacancies in InVO 4 , in comparison to simple oxides. • Active sites and gas sensitivity of nanosized InVO 4 , V 2 O 5 and In 2 O 3 are compared • Different surface acidity of In 2 O 3 , InVO 4 , and V 2 O 5 and the effect of cations • Easier reducibility and oxygen vacancy formation in InVO 4 than in simple oxides • Superior sensitivity to NO 2 at 150 °C of InVO 4 and persistence to humidity changes • Different NO 2 sensing mechanisms of InVO 4 and In 2 O 3 and effect of oxygen vacancies [ABSTRACT FROM AUTHOR]

Extremely toxic nitrogen dioxide (NO 2) was detected using lamellar layered α-MoO 3. The stable orthorhombic phase of MoO 3 (α-MoO 3) with preferential growth along (02k0) and the nano-rectangular rods (NRs) like morphology were observed. The incorporation of Mg2+ in α-MoO 3 influenced the morphology and the oxygen vacancies (V O), which were analyzed through Raman, photoluminescence, and X-ray photoelectron spectroscopy. The core level spectra provided direct evidence for V O enrichment in 3 %Mg-α-MoO 3 via emergence of peak at 531.02 eV with an area of 45.15 %. NO 2 response was analyzed at 150–200 °C with various NO 2 concentrations. 3 %Mg-α-MoO 3 NRs provided maximum response of 133.9 % for 50 ppm with low limit of detection (LOD) of 250 ppb with good response (193 s) and recovery (260 s) transient behaviors. The fabricated sensor shows high selectivity to NO 2 among H 2 S, SO 2 , N 2 O, and NH 3 , also good repeatability suggesting potential suitability for NO 2 detection. [Display omitted] • α-MoO 3 has preferential growth along (02k0) plane confirming the well lamellar stacks via Mg doping. • Aliovalent Mg2+ stimuli the aspect ratio of the Lamellar stacked nanorods, resulting in stronger solid-gas interactions. • Mg doped α-MoO 3 exhibits excellent Long-term selectivity for NO 2 , quick response and good stability. • The high selectivity about 133.9% and low detection limit (250 ppb) offers promising sensor applications. [ABSTRACT FROM AUTHOR]

In the troposphere, ozone (O 3) formation can be limited by NOx, VOCs, or both, complicating efforts to reduce O 3 by controlling its precursors. This study used formaldehyde (HCHO) data and nitrogen dioxide (NO 2) data from the Ozone Monitoring Instrument (OMI) to analyze O 3 formation sensitivity in Fujian from 2012 to 2021. Over the past decade, an 8.7% reduction in NO 2 VCDs and a 9.91% increase in HCHO VCDs were observed. Due to differences in the primary driving factors, HCHO VCDs exhibit a characteristic seasonal pattern with higher in summer and lower in winter, whereas NO 2 VCDs show the opposite trend. O 3 formation chemistry was accurately diagnosed by combining satellite-based data and ground-based O 3 data. A new threshold value (3.3–4.6) was derived to determine the transition from VOC-limited to NOx-limited O 3 formation regimes. Results showed that O 3 sensitivity exhibited pronounced seasonal variations. The VOC-limited regime predominates throughout the entire Fujian region in winter, whereas it occupies only 5% of the area in summer. A VOC-limited region was found widely across Fujian on an annual average, but it decreased by 24% over 10 years. Transitional areas experienced a 19% increase. In two natural emission reduction cases (reductions during the Chinese Lunar New Year holiday and reductions in weekend traffic emissions compared to weekdays), ground-level O 3 effectively captured the impacts of sensitivity changes. The impact suggests that when Fujian is in the VOC control region, a significant reduction in NO x , without effective VOC control, might lead to an O 3 increase. The importance of controlling VOC emissions is highlighted in Fujian. This study enhances the understanding of O 3 formation regimes in southeastern China, which is crucial for developing O 3 prevention and control strategies. [Display omitted] • A threshold value of HCHO/NO 2 was derived to delineate O 3 formation regimes. • O 3 formation regimes exhibit significant variations across different cities and seasons. • Emission strategies need to focus on reducing VOC emissions. • Ground O3 captured the impact of sensitivity changes based on the threshold values. [ABSTRACT FROM AUTHOR]

The mechanisms underlying relationships between ambient air pollution and chronic obstructive pulmonary disease (COPD) risk remained largely uncertain. In this study, we aim to evaluate whether metabolic signature comprising multiple circulating metabolites can characterize metabolic response to the multiple air pollution; and to assess whether the identified metabolic signature contribute to COPD risk. A total of 227,962 participants with complete data were included from the UK biobank study. Concentrations of nitrogen dioxide (NO 2), nitrogen oxides (NO x), and particulate matter (PM 2.5 and PM 10) were evaluated by land-use regression models. We newly computed an air pollution score to reflect joint exposure to multiple air pollutants. Circulating metabolome was quantified by nuclear magnetic resonance (NMR) spectroscopy. During a median of 12.78 years of follow-up, a total of 8685 incident COPD cases were documented. After multiple correction, the Cox regression models showed that 102 of 143 metabolites were significantly associated with COPD risk. Utilizing elastic net regularized regressions, we identified a metabolic signature comprising 106 metabolites (including lipid, fatty acids, glycolysis and amino acids et al.) were robustly related to air pollution score. In the multivariate-adjusted Cox regression models, the derived metabolic signature showed a positive correlation with incident COPD [HR per SD = 1.20 (95% CI: 1.17–1.22)]. Casual mediation analysis further noted that the constructed metabolic signature mediated 10.5 % (8.3%–13.1%) of the air pollution-COPD associations. Taken together, our findings identified a metabolic signature that captured metabolic response to various air pollutants exposure jointly, and predicted future COPD risk independent of known risk factors. [Display omitted] • Joint exposure to air pollutants were positively associated with COPD incidence. • A metabolic signature consists of 106 metabolites was related to air pollution score. • The derived metabolic signature can predict future COPD risk. • The metabolic signature partly mediated air pollution-incident COPD association. [ABSTRACT FROM AUTHOR]

As the two important ambient air pollutants, particulate matter (PM 2.5) and ozone (O 3) can both originate from gas nitrogen oxides. In this study, applied by theoretical analysis and machine learning method, we examined the effects of atmospheric reactive nitrogen on PM 2.5 -O 3 pollution, in which nitric oxide (NO), nitrogen dioxide (NO 2), gaseous nitric acid (HNO 3) and particle nitrate (pNO 3 −) conversion process has the co-directional and contra-directional effects on PM 2.5 -O 3 pollution. Of which, HNO 3 and SO 2 are the co-directional driving factors resulting in PM 2.5 and O 3 growing or decreasing simultaneously; while NO, NO 2 , and temperature represent the contra-directional factors, which can promote the growth of one pollutant and reduce another one. Our findings suggest that designing the suitable co-controlling strategies for PM 2.5 -O 3 sustainable reduction should target at driving factors by considering the contra-directional and co-directional effects under suitable sensitivity regions. For co-directional driving factors, the design of suitable mitigation strategies will jointly achieve effective reduction in PM 2.5 and O 3 ; while for contra-directional driving factors, it should be more patient, otherwise, it is possible to reduce one item but increase another one at the same time. [Display omitted] • Atmospheric reactive nitrogen conversion regulates PM 2.5 -O 3 pollution. • The co-directional and contra-directional effects on PM 2.5 -O 3 pollution. • HNO 3 and SO 2 facilitate PM 2.5 and O 3 growing or decreasing, simultaneously. • NO x and temperature can promote the growth of one pollutant and reduce another one. [ABSTRACT FROM AUTHOR]

An increasing evidence links air pollution to breast cancer (BC) risk. Yet, pollutant exposure estimates at the workplace location in pollution exposure assessment have not been considered. This study investigates the association between particulate matters (PM 2·5 , PM 10) and nitrogen dioxide (NO 2) atmospheric concentrations (1990–2011), at the women's residential and workplace locations, and BC risk. This case-control study of 2419 BC cases and 2984 controls, was nested in the French prospective E3N cohort. The annual mean PM 2·5 , PM 10 and NO 2 concentrations were estimated using a Land Use Regression model (50 m x 50 m resolution) and assigned to the women's geocoded residential and workplace locations, from cohort recruitment to their index date (date of case diagnosis). Odds ratios (OR) and 95 % confidence intervals (CI) were estimated using multivariate logistic regression models. An increased BC risk was observed for a 10 µg/m3 increase of the 1990–2011 average PM 2·5 concentration estimates (OR=1·28; CI 1·00, 1·63). An increased risk was suggested for a 10 µg/m3 increase for PM 10 (OR=1·09; CI 0·92, 1·30) and NO 2 (OR=1·05; CI 0·97, 1·13). No effect modification by menopausal status, nor difference by hormone receptor status were observed. This study is the first to estimate BC risk and long-term air pollutant exposure from both, residential and workplace location histories. Results suggest that residential PM 2·5 , PM 10 and NO 2 concentrations are strongly correlated with workplace ones, indicating that residential data may serve as proxy for overall exposure. Future studies should consider exposure during commuting. • First study on air pollution effect using both residential and workplace addresses. • Exposure to PM 2.5 was significantly associated with an increased breast cancer risk. • An increased risk was suggested for exposure to PM 10 and NO 2. • Findings were comparable when using only residence concentration estimates. [ABSTRACT FROM AUTHOR]

The chemical kinetics of the second–H-abstraction and the third-H-abstraction reactions of monomethylhydrazine (MMH) and nitrogen dioxide (NO 2) and its application to modeling hypergolic ignition of MMH/NO 2 were investigated in this work. Potential energy surfaces (PESs) for the key reactions were obtained by employing the CCSD(T)/CBS//M06-2X/6-311++G(d,p) single-reference method and the MRCI(7e,6o)/CBS//M06-2X/6-311++G(d,p) multi-reference method. The RRKM/Master Equation approach was used to calculate the temperature- and pressure-dependent rate constants. For the second-H-abstraction reactions, the trans-CH 3 NNH and HNO 2 /HONO are the major products. For the third-H-abstraction reactions, the bimolecular reaction of cis-CH 3 NNH+NO 2 →CH 3 NN+HNO 2 is more favorable. The calculated rate constants and thermodynamics data were fitted and incorporated into two existing mechanisms to investigate their influence on modeling MMH/NO 2 hypergolic ignition. The modeling results show that the system reactivity of MMH/NO 2 is promoted by the second- and third-H-abstraction reactions, as the ignition delay times decrease by a factor of two at 300–800 K. The production rate and sensitivity analyses further validate the significance of the second-H-abstraction reactions at low temperatures. The sensitivity analyses at 1000 K also indicate the necessity of further investigations on CH 2 O, N 2 H 2 /NO 2 , and CH 3 NH/NO 2 sub-mechanisms for modeling the MMH/NO 2 combustion at high temperatures. This work provides not only new kinetic and thermochemical data but also a better understanding of the hypergolic ignition of MMH/NO 2. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cubic/orthorhombic WO 3 was in-situ synthesized by silicotungstic acid precursor. • The POMs-derived c/o-WO 3 exhibits good sensing performance to ppb-level NO 2. • The optimal response value to 500 ppb NO 2 gas is 5.239 with very high selectivity. • o-WO 3 /c-WO 3 can form an internal electric field that promotes carriers separation. • Other gas sensitive parameters were comprehensively explored. WO 3 is a representative metal oxide semiconductor gas sensing material with good selectivity and high sensitivity. However, high electron-hole recombination is a common drawback of WO 3 -based gas sensors. Here, we used silicotungstic acid (SiW 12), a classical Keggin-type polyoxometalate (POM) as precursor. After oxidation, WO 3 with cubic/orthorhombic mixed-phase were in-situ formed. Gas sensing performances of the WO 3 to ppb-level NO 2 gas were tested to explore whether the POM-derived WO 3 has advantage for gas sensor applications. Surprisingly, the c/o-WO 3 calcined at 800 °C exhibit a response value of 5.239 to 500 ppb NO 2 with very high selectivity, good long-term stability, repeatability and humidity resistance. By mechanism analysis, the bandgap positions of o-WO 3 and c-WO 3 are staggered, forming an internal electric field that favours electron-hole separation and improves the gas sensing performance. This work transforms POMs into two-phase mixed WO 3 , providing a new idea for the application of POMs as precursors in gas sensors. [ABSTRACT FROM AUTHOR]

Sulfate aerosol (SO 4 2−) is an important factor leading to acid rain and aggravating atmospheric particulate pollution. SO 4 2− is mainly converted from gaseous SO 2 , in which the oxidant gas NO 2 may play a key role. In real atmosphere with complexity and nonlinearity, the impact of NO 2 on SO 2 –SO 4 2- conversion exhibits scale dependence due to the combined effect of meteorology, atmospheric chemistry, and pollution emission. Here, based on the long-term atmospheric precipitation data from 2014 to 2021 of Nanchong City in the Sichuan Basin, the Extended Ensemble Empirical Mode Decomposition (EEMD) and Multifractal Detrended Cross-Correlation Analysis (MF-DCCA) methods have been employed to analyze the nonlinear correlations between gaseous SO 2 and SO 4 2− in rainwater at different time scales. A multifractal parameter Δ h has been described as the scaling features of SO 2 –SO 4 2- conversion efficiency in the real atmosphere. Then, the impact of NO 2 on SO 2 –SO 4 2- conversion in cold and warm seasons has been quantified, using sliding window analysis and Pearson correlation analysis. The results show that NO 2 significantly promoted SO 2 –SO 4 2- conversion in the cold season, but had little effect on it in the warm season. As direct evidence from atmospheric precipitation analysis, this finding has provided a new theoretical basis for evaluating the impact of NO 2 on secondary aerosol generation. [Display omitted] • Long-term precipitation data from the southwestern city of China are analyzed. • Decomposing data shows that SO 4 2− responded nonlinearly to changes of gaseous precursors. • Multifractal method is introduced as a tool for describing the effect of NO 2 on SO 2 –SO 4 2- conversion. • NO 2 promotes the conversion of SO 2 –SO 4 2- in cold season. • The precipitation component analysis reveals the key information of sulfate aerosol formation mechanism. [ABSTRACT FROM AUTHOR]

In this work, we have fabricated hybrid nanocomposites of WS 2 /rGO using facile hydrothermal method for room temperature based NO 2 gas detection. The synthesized WS 2 /rGO nanocomposites showed p-type response with improved sensitivity and selectivity towards NO 2 gas. The pristine WS 2 nanosheets showed response around 21 % whereas the WS 2 /rGO nanocomposites showed an improved response of 82 % towards 10 ppm NO 2 gas molecules. The response and recovery time towards 10 ppm NO 2 gas was around 26 s/553 s and 58 s/627 s for pristine WS 2 and WS 2 /rGO nanocomposites, respectively. The prepared WS 2 /rGO nanocomposites showed high selectivity towards NO 2 gas. Further, the long-term stability and repeatability studies were carried out and the results indicate the potential utilization of WS 2 /rGO nanocomposite towards NO 2 gas detection at room temperature. [Display omitted] • rGO/WS 2 nanocomposites were successfully synthesized using facile hydrothermal method and subsequent annealing technique. • The gas sensing performance of WS 2 and rGO/WS 2 nanocomposites were investigated showing excellent selectivity of NO 2 at RT. • GW-10 shows enhanced response of 85 % towards 10 ppm NO 2 with short response/ recovery time of 58 s / 627 s respectively. • Gas sensing mechanism of rGO/WS 2 nanocomposites were discussed. [ABSTRACT FROM AUTHOR]

• Low-cost measurement platform for NO2 monitoring developed. • Machine-learning-based calibration procedure proposed. • Combination of neural network and kriging surrogates employed. • NO2 sensor correction applied using reference data and environmental parameters. • Satisfactory correlation between reference and calibrated sensor data demonstrate. Air quality significantly impacts human health, the environment, and the economy. Precise real-time monitoring of air pollution is crucial for managing associated risks and developing appropriate short- and long-term measures. Nitrogen dioxide (NO 2) stands as a common pollutant, with elevated levels posing risks to the human respiratory tract, exacerbating respiratory infections and asthma, and potentially leading to chronic lung diseases. Notwithstanding, precise NO 2 detection typically demands complex and costly equipment. This paper explores NO 2 monitoring using low-cost platforms, meticulously calibrated for reliability. An integrated measurement unit is first presented that contains primary and supplementary nitrogen dioxide sensors, as well as auxiliary detectors for evaluating outside and inside temperature and humidity. The calibration process utilizes data acquired over the period of five months from various reference stations. Employing machine learning with an artificial neural network (ANN)-based and kriging interpolation surrogate models, the correction strategy integrates additive and multiplicative enhancement, predicted by the ANN through auxiliary sensor data such as temperature, humidity, and the sensor-detected NO 2 levels. Extensive verification studies showcase that this calibration approach notably enhances monitoring precision (coefficient of determination surpassing 0.85 concerning reference data, and RMSE of less than four μg/m3), rendering low-cost NO 2 detection practical and dependable. [ABSTRACT FROM AUTHOR]

China's O 3 pollution events continue to be frequent, and accurately understanding the sources and sinks of O 3 pollution is crucial. Previous research predominantly focused on controlling O 3 pollution through daytime photochemical production, overlooking the significant impact of nocturnal high O 3 values on the subsequent days' O 3 concentrations. Understanding the causes of nocturnal O 3 pollution and implementing effective control measures are essential for O 3 pollution alleviation. In light of this, we utilized clustering analysis, combined with meteorological and chemical factors to comprehend the nocturnal variation characteristics and mechanisms of nocturnal O 3 increase (NOI) events in Tai'an from July 2021 to June 2022. The results qualitatively identified that three clusters have distinct influencing factors: horizontal transport predominantly drives NOI flucts , meanwhile, NOI decline events, mainly occurring in summer, experienced more intense photochemical reactions. For NOI stable events, primarily observed in spring, there was greater downward transport of high-altitude O 3 and more intense titration reactions. Further, using interpretable machine learning models, we quantitatively assessed the contributions of several factors to nocturnal O 3. The results reveal that nocturnal titration is the predominant factor, followed by the accumulation of daytime photochemical generation. Additionally, we explored approaches for reducing daytime nitrogen dioxide (NO 2) and formaldehyde (HCHO), quantifying their impact on nocturnal O 3 concentrations. The results indicate that reducing emissions of HCHO and NO 2 can effectively lower O 3 levels in NOI decline and focusing on reducing HCHO emissions proves to be more beneficial in NOI stable events, with NOI flucts events falling in between these two clusters. Targeted implementation of diverse reduction approaches and proportions in different NOI clusters can more effectively mitigate the occurrence of nocturnal O 3 pollution, thereby influencing the O 3 levels of the following day. • High nocturnal O 3 levels constitute a significant factor leading to subsequent O 3 exceedances. • Nocturnal O 3 increase events, with diverse temporal patterns, are classified by K-means clustering. • Machine learning is used to assess impact factors for nocturnal O 3. • Nocturnal O 3 events in different clusters and seasons require tailored emission reduction approaches. [ABSTRACT FROM AUTHOR]

SO 2 and NO 2 mixture widely exists in the desorbed gas from industrial flue gas adsorption purification process, separating the mixture into pure gas provides the key step for success in recycling them into profitable chemicals. However, effective SO 2 /NO 2 separation is challenged due to the similar properties of both gases. In this work, we report the synthesis of an industrially-favored NaA zeolite membrane and the utilization of this membrane for SO 2 /NO 2 separation in order to address the above-mentioned challenge. Various characterizations illustrate that the in-situ synthesis endows the NaA zeolite membrane with well-intergrown crystals, high continuity, and crystal-comparable thickness. The separation measurements at different feed pressure, temperature, and gas composition demonstrate that the NaA zeolite membrane shows superior separation performance (SO 2 /NO 2 separation factor of 40.0, SO 2 permeance of 2.93 × 10−7 mol m−2 Pa−1 s−1 at 293 K and 0.2 MPa) with strong stability (more than 7 d) compared to the previous best-performing zeolite membrane. The strong competitiveness of SO 2 over NO 2 on the low-silica membrane is revealed through molecular simulation, showing that the great affinity of SO 2 with highly-polar zeolite structure benefits the SO 2 gas preferential adsorption and energetically barrier-free permeation through the eight-membered ring of NaA zeolite. This work not only showcases an efficient strategy for the SO 2 /NO 2 separation, but also expands the gas separation application of zeolite membranes. [Display omitted] • NaA zeolite membrane with good quality is synthesized by the in-situ growth. • Effects of pressure, temperature, and composition on SO 2 /NO 2 separation are studied. • SO 2 /NO 2 separation factor of 40 and SO 2 permeance of 875 GPU are stably achieved. • Adsorption competitiveness of SO 2 over NO 2 on NaA zeolite membrane is revealed. • SO 2 shows energetically barrier-free permeation through eight-membered ring of NaA. [ABSTRACT FROM AUTHOR]

This study investigates the potential of Al-decorated ZnO nanomaterials as a sensing material for detecting noxious nitrogen dioxide (NO 2) gas. A series of samples with varying Al concentrations (0–6 mol%) were synthesized using a simple co-precipitation method. The structural, morphological, and spectral characteristics of the materials were thoroughly characterized using XRD, XPS, FESEM and EDX, HRTEM, BET, FTIR, and UV–Visible spectroscopy techniques. The prepared samples were investigated for the detection of NO 2 gas at various concentrations (1–20 ppm) and at different operating temperatures (140°C–220 °C). Notably, the 2 mol% Al-decorated ZnO nanomaterial exhibited the highest NO 2 gas sensing response, reaching a maximum value of 7.82 at 20 ppm concentration and 180 °C working temperature. The 2 mol% Al-decorated ZnO sensor demonstrated remarkable attributes, including rapid response and recovery times, consistent performance across a broad temperature range, excellent reproducibility, and stability. The study also investigated the mechanism underlying NO 2 gas sensing by Al-decorated ZnO sensors and discussed the findings. The results of this study suggest that Al-decorated ZnO nanorods, particularly the 2 mol% Al-decorated ZnO sensor, have potential for NO 2 gas detection in environmental monitoring and industrial applications. • A range of sensors were synthesized, including pure ZnO and ZnO decorated-aluminium. • The 2 mol% Al-decorated sensor exhibited exceptional performance in detecting hazardous NO 2 gas. • The study explored the sensing mechanism of Al-decorated ZnO sensors for NO 2 gas, offering detailed analysis and discussion. [ABSTRACT FROM AUTHOR]

In this study, we present a unique technique utilizing POT/SnO 2 nanocomposites to create an ultrafast and extremely sensitive nitrogen dioxide gas sensor. Various characterization approaches, including XRD, FE-SEM, UV–Vis spectroscopy, Raman spectroscopy, and FTIR, were systematically applied to verify the successful synthesis of the POT/SnO 2 nanocomposite. We tested the conductivity and sensing efficiency with an emphasis on the chemosensitivity component. The sensor based on POT/SnO 2 has remarkable sensitivity over a broad range of NO 2 concentrations from 5 to 650 ppm. Our results indicate that the incorporation of SnO 2 into POT significantly enhanced the sensor sensitivity, increasing from 26 % for pure POT to 87 % for the composite. This improvement produced rapid response and recovery times of 47 s and 44 s, respectively, along with remarkable long-term stability at room temperature. With its remarkable sensitivity and performance characteristics, our sensor emerges as a strong contender for real-time nitrogen dioxide detection, representing a noteworthy advancement in gas sensing technology. [Display omitted] • This work demonstrated remarkable sensitivity over a broad range of NO 2 concentrations, from 5 ppm to 650 ppm. • The incorporation of SnO 2 into POT significantly enhanced sensor sensitivity. • The simplified and efficient development process contributes to the sensor's accessibility and practicality. • The proposed sensor emerges as a strong contender for real-time Nitrogen dioxide detection. [ABSTRACT FROM AUTHOR]

Regular monitoring of the air pollutant nitrogen dioxide (NO 2), an indicator for traffic-related emissions, is a priority in urban environments. The health impacts associated with NO 2 exposure are the result of a combination of factors, including concentration, duration of exposure, and interactions with other pollutants. WHO has established air quality guidelines based on epidemiological studies. This study develops a new concept "Health Impact Pathways (HIPs)" using adversity as a probabilistic indicator of health effects. For this purpose, it integrates available toxicological and epidemiological information, using Adverse Outcome Pathways (AOPs), in order to understand chemical-biological interactions and their consequences on health. Literature review and meta-analysis of toxicological data supported by expert judgment were performed to establish: a) adversity pathways, b) quantitative criteria for scoring the observed toxicological effects (adversity indicators), c) NO 2 exposure - adversity relationship for both long-term (1–36 months) and shortterm (1–7 days). The NO 2 daily concentrations from January 2001 to December 2022, were obtained from Madrid city Air Quality network monitoring database. Adversity levels were compared with relative risk levels for all-cause and respiratory mortality estimated using linear equations from WHO 2021 guidelines. Non-linear relations were obtained for all long- and short-term NO 2 related adversity indicators; for long-term effects, the best fitting was obtained with a modified Haber's law model with an exponential coefficient for the exposure time of 0.25. Estimations are presented for a set of case studies for Madrid city, covering temporal and spatial variability. A clear improvement trend along the two decades was observed, as well as high inter- and intra-station variability; the adversity indicators provided integrated information on the temporal and spatial evolution of population level risk. The proposed HIP conceptual approach offers promising advances for integrating experimental and epidemiological data. The next step is linking the concentration-adversity relationship with population health impacts through probability estimations, the preliminary estimations confirm the need for assessing independently different population groups. [Display omitted] • Extending AOP as Health Impact Pathways-HIP gives quantitative adversity estimates. • The HIP conceptual approach integrates experimental tox and epidemiological data. • Nonlinearity of NO 2 -related long/short-term health impacts must feed trend analysis. • The estimates confirm the need to independently assess different population groups. [ABSTRACT FROM AUTHOR]