Résumé
Volatile organic compounds (VOCs) have direct influences on air quality and climate. They indeed play a key role in atmospheric chemistry as precursors of secondary pollutants, such as ozone (O3) and secondary organic aerosols (SOA). In this respect, long-term datasets of in situ atmospheric measurements are crucial for characterizing the variability of atmospheric chemical composition, its sources, and trends. The ongoing establishment of the Aerosols, Cloud, and Trace gases Research InfraStructure (ACTRIS) allows implementation of the collection and provision of such high-quality datasets. In this context, online and continuous measurements of O3, nitrogen oxides (NOx), and aerosols have been carried out since 2012 at the SIRTA (Site Instrumental de Recherche par Télédétection Atmosphérique) observatory, located in the Paris region, France. Within the last decade, VOC measurements were conducted offline at SIRTA, until the implementation of real-time monitoring which started in January 2020 using a proton-transfer-reaction quadrupole mass spectrometer (PTR-Q-MS).The dataset acquired during the first 2 years of online VOC measurements provides insights into their seasonal and diurnal variabilities. The additional long-term datasets obtained from co-located measurements (NOx, aerosol physical and chemical properties, meteorological parameters) are used to better characterize the atmospheric conditions and to further interpret the obtained results. Results also include insights into VOC main sources and the influence of meteorological conditions and air mass origin on their levels in the Paris region. Due to the COVID-19 pandemic, the year 2020 notably saw a quasi-total lockdown in France in spring and a lighter one in autumn. Therefore, the focus is placed on the impact of these lockdowns on the VOC variability and sources. A change in the behaviour of VOC markers for anthropogenic sources was observed during the first lockdown, reflecting a change in human activities. A comparison with gas chromatography data from the Paris city centre consolidates the regional representativity of the SIRTA station for benzene, while differences are observed for shorter-lived compounds with a notable impact of their local sources. This dataset could be further used as input for atmospheric models and can be found at 10.14768/f8c46735-e6c3-45e2-8f6f-26c6d67c4723 (Simon et al., 2022a).
Résumé
OBJECTIVE: Proton pump inhibitors (PPI) are among the most prescribed drugs worldwide; therefore, assessing their effect on COVID-19 infection symptoms and severity is of great importance. This study was designed to evaluate the role of previous PPI consumption on the clinical presentation and severity of COVID-19. PATIENTS AND METHODS: All adult COVID-19 patients were eligible in this observational cross-sectional study. The patients' demographic and clinical data, history of PPI consumption, and comorbid disease were recorded. Charlson comorbidity index (CCI) and quick COVID-19 severity index (qCSI) score were calculated for each patient. IBM SPSS version 25 was used for statistical analysis. RESULTS: Totally 670 patients completed the study (PPI users=121). The average severity (qCSI) score of PPI user patients with comorbidity score of zero was significantly higher than non-users (P-value=0.001). Mortality rate was 6.6% and 3.8% in PPI-users and non-users respectively (P-value=0.117). PPI users were significantly more symptomatic compared to non-users (P-value=0.001). CONCLUSION: We found that PPI users were meaningfully more symptomatic and had a higher severity (qCSI) score. Rational prescription of PPIs should be considered by physicians during and after the pandemic.
Résumé
Introduction: One of the known adverse reactions among long-term proton pump inhibitor (PPI) users, especially the elderly, is that it increases the risk of community-acquired pneumonia [1]. The probable mechanism is that the increase in gastric pH produces a decrease in elimination or an increase in colonization of bacteria;PPIs promote the proliferation of bacteria in the mouth and oropharynx and would increase in this manner the risk of pneumonia [2]. In COVID-19, lungs are particularly at risk. Currently, there is a great interest in establishing the relationship between the severity and mortality of SARS-CoV-2 infection in patients using PPIs [3]. Objective: To explore the relationship between the previous use of PPIs and mortality due to COVID-19 Methods: A retrospective observational study was carried out in a tertiary care hospital in Lima, Peru. Patients hospitalized in March 2021 for severe SARS-CoV-2 infection, confirmed by molecular tests (reverse transcription polymerase chain reaction), were included. Severe COVID-19 disease was defined as peripheral oxygen saturation on admission less than 93% (without supplemental oxygen) or pulmonary involvement greater than 30% (on the total severity score or TSS) in the lung tomography Results: A total of 327 patients entered the study (mean age, 61.36 ± 16.0 years;male, 59.95%). PPIs users and non-users were 10 (3.06%) and 317 (96.94%), respectively. The mean age, Charlson score and total severity score (TSS) between PPIs users and non-users were 68.8 ± 17.11 vs. 61.12 ± 15.93 (p = 0.134), 3.6 ± 2.32 vs. 2.25 ± 1.715 (p = 0.019) and 55 ± 25.28 vs. 48.44 ± 24.30 (P = 0.399), respectively. Mortality in those using and not using PPIs were 80.0% (8 out of 10) and 38.49% (122 out of 317), respectively (Crude odds ratio, 6.39;95% confidence interval 1.34-30.61;p = 0.008). No significant difference was observed in the leukocyte count, mean lactate dehydrogenase concentration, Ferritin, D-dimer and fibrinogen and serum levels of C-Reactive Protein, in those users of PPIs compared to nonusers. Conclusion: Among hospitalized patients for severe SARS-CoV-2 infection, prior use of PPIs was associated with a higher mortality risk. This association does not necessary imply causality. Further research would be required to clarify potential mechanisms.
Résumé
The outbreak of COVID-19 promoted strict restrictions to human activities in China, which led to a dramatic decrease in most air pollutant concentrations (e.g., PM2.5, PM10, NOx, SO2 and CO). However, an obvious increase in ozone (O3) concentrations was found during the lockdown period in most urban areas of China. In this study, we conducted field measurements targeting ozone and its key precursors by utilizing a novel proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) in Changzhou, which is representative of the Yangtze River Delta (YRD) city cluster of China. We further applied the integrated methodology including machine learning, an observation-based model (OBM) and sensitivity analysis to obtain insights into the reasons causing the obvious increase in ozone. Major findings include the following: (1) by deweathered calculation, we found changes in precursor emissions contributed 1.46 ppbv to the increase in the observed O3 during the full-lockdown period in 2020, while meteorology constrained 3.0 ppbv of O3 in the full-lockdown period of 2019. (2) By using an OBM, we found that although a significant reduction in O3 precursors was observed during the full-lockdown period, the photochemical formation of O3 was stronger than that during the pre-lockdown period. (3) The NOx/VOC ratio dropped dramatically from 1.84 during the pre-lockdown to 0.79 in the full-lockdown period, which switched O3 formation from a VOC-limited regime to the boundary of a NOx- and VOC-limited regime. Additionally, box model results suggested that the decrease in the NOx/VOC ratio during the full-lockdown period could increase the mean O3 by 2.4 ppbv. Results of this study give insights into the relationship between O3 and its precursors in urban area and demonstrate reasons for the obvious increase in O3 in most urban areas of China during the COVID-19 lockdown period. This study also underlines the necessity of controlling anthropogenic oxygenated volatile organic compounds (OVOCs), alkenes and aromatics in the sustained campaign of reducing O3 pollution in China.