ABSTRACT
Linear contrails and contrail cirrus induced by global aviation have long been known to contribute to climate change by warming the atmosphere. Besides increasing global cirrus cloudiness, aviation may also alter the properties of natural cirrus clouds by soot emissions which lead to more heterogeneous freezing. During the first COVID-19 lockdown in Europe, changes in the properties and occurrence of cirrus clouds were determined with the lidar measurements of CALIPSO, which are presumed to be caused by the corresponding reduction in civil aviation. In the 10 years before the COVID-19 outbreak, however, aviation grew strongly in terms of CO2 emissions and flight densities in Europe. In this study, 10-year lidar measurements with CALIPSO are analysed to determine the seasonality and long-term trends in cirrus clouds as well as their correlations with the ambient temperatures and air traffic. The results show that there is a distinct seasonal cycle in the occurrence rates (ORs) and particle linear depolarization ratio (PLDR) of cirrus clouds. In addition, cirrus clouds appear within a broader altitude range in winter than in summer and they are characterized by larger OR and PLDR values in winter than in summer. The monthly medians of PLDR as well as their deseasonalized time series in the 10-year period before COVID-19 both show positive trends, which are statistically significant according to the Mann-Kendall (MK) significance test. However, the ORs of cirrus clouds show a negative trend, which might be connected with the background meteorological conditions. Since the cirrus PLDR strongly depends on the ambient temperatures, the contributions induced by temperature are further removed from the cirrus PLDR with a simple linear regression model. The derived residuals show significant positive trends according to the MK test. To compare the cirrus PLDR and air traffic (with the CO2 emissions from aviation as a proxy), the deseasonalization of both datasets were previously conducted since the seasonal cycles in both are not consistent. The deseasonalized time series determined for the cirrus PLDR and CO2 emissions from aviation both show increasing trends and their correlation coefficient is r=0.54 at the confidence level above 99.5 %. Finally, comparisons between the cirrus PLDR and aviation in every season were made and revealed a strong correlation in other seasons than in summer.
ABSTRACT
During spring 2020, the COVID-19 pandemic caused massive reductions in emissions from industry and ground and airborne transportation. To explore the resulting atmospheric composition changes, we conducted the BLUESKY campaign with two research aircraft and measured trace gases, aerosols, and cloud properties from the boundary layer to the lower stratosphere. From 16 May to 9 June 2020, we performed 20 flights in the early COVID-19 lockdown phase over Europe and the Atlantic Ocean. We found up to 50% reductions in boundary layer nitrogen dioxide concentrations in urban areas from GOME-2B satellite data, along with carbon monoxide reductions in the pollution hot spots. We measured 20%-70% reductions in total reactive nitrogen, carbon monoxide, and fine mode aerosol concentration in profiles over German cities compared to a 10-yr dataset from passenger aircraft. The total aerosol mass was significantly reduced below 5 km altitude, and the organic aerosol fraction also aloft, indicative of decreased organic precursor gas emissions. The reduced aerosol optical thickness caused a perceptible shift in sky color toward the blue part of the spectrum (hence BLUESKY) and increased shortwave radiation at the surface. We find that the 80% decline in air traffic led to substantial reductions in nitrogen oxides at cruise altitudes, in contrail cover, and in resulting radiative forcing. The light extinction and depolarization by cirrus were also reduced in regions with substantially decreased air traffic. General circulation-chemistry model simulations indicate good agreement with the measurements when applying a reduced emission scenario. The comprehensive BLUESKY dataset documents the major impact of anthropogenic emissions on the atmospheric composition.
ABSTRACT
AIMS OF THE STUDY: There is increasing interest in better understanding of long COVID, a condition characterised by long-term sequelae-appearing or persistingafter the typical convalescence period-of coronavirus disease 2019 (COVID-19). Herein, we describe long-term outcomes regarding residual symptoms and psychological distress in hospitalised patients 1 year after COVID-19. METHODS: This prospective cohort study included consecutive adult patients hospitalised for confirmed COVID-19 in two Swiss tertiary-care hospitals between March and June 2020. The primary endpoint was evidence of long COVID 1 year after discharge, defined as =1 persisting or new symptom related to COVID-19, from a predefined list of symptoms. Secondary endpoints included psychological distress and symptoms of post-traumatic stress disorder (PTSD). RESULTS: Among 90 patients included in the study, 63 (70%) had symptoms of long COVID 1 year after hospitalisation, particularly fatigue (46%), concentration difficulties (31%), shortness of breath (21%) and post-exertion malaise (20%). Three predictors, namely duration of hospitalisation (odds ratio [OR] 1.11, 95% confidence interval [CI] 1.00-1.22;p = 0.041), severity of illness (OR 1.19, 95% CI 1.04-1.37;p = 0.013), and self-perceived overall health status 30 days after hospitalisation (OR 0.97, 95% CI 0.94-1.00;p = 0.027) were associated with long COVID. Regarding secondary endpoints, 16 (18%) experienced psychological distress and 3 (3.3%) patients had symptoms of PTSD. CONCLUSION: A high proportion of COVID-19 patients report symptoms of long COVID 1 year after hospitalisation, which negatively affects their quality of life. The most important risk factors were severe initial presentation of COVID-19 with long hospital stays.
ABSTRACT
We reported the results of our multicenter cohort study in all patients who presented for endoscopy between March 1 and May 17 and were evaluated before their endoscopy for SARS-CoV2 and were followed after their endoscopy for COVID-19 status. This cohort enabled us to calculate the conversion rate from COVID-19 negative to positive during the study period and evaluate the change in conversion rate with the implementation of social distancing and masking at the population level in New York City. Data were retrieved from electronic medical records systems of six tertiary care centers in New York City. We identified all adult patients who had endoscopy between March 1, and May 17, 2020. Conversion was defined as having a negative COVID-19 status before endoscopy and a positive status afterwards. Participants COVID-19 status was defined based on SARS-CoV2 PCR test or a combination of symptoms (Fever plus at least one of: dyspnea, cough, dysgeusia, or anosmia). Patients were evaluated before endoscopy and then by phone or telehealth visit afterwards. Spline regression was used to evaluate the conversion rate before and after adoption of social distancing (March 20, 2020) and mandatory masks (April 15, 2020) in New York City. Of the 1467 patients presenting for endoscopy during the study period, we had follow-up data on 1222 patients (51% outpatient and 49% inpatient endoscopies). Overall, 78 participants (6.38 %) converted after endoscopy (74 with a positive PCR, and 4 with symptoms as defined above), at a median of 23 days after endoscopy (IQR 11 to 42 days). Patients had a mean age of 62±15 years, and were 62% male (n=48). Multivariable analysis demonstrated that date of endoscopy, institution, and presence of cardiovascular disease were the independent predictors of conversion after endoscopy, with cardiovascular disease associated with a more than 2 fold increase in the risk of conversion (OR=2.1, 95%CI 1.2-3.6, p=0.009). The range of conversion from the six institutions varied widely (1 to 11%, p=0.035). Overall, participants whose endoscopies were performed later during the study period had a lower risk of conversion (OR for one week=0.87, 95%CI 0.80-0.94, p=0.001). Before social distancing, conversion rate was 8.4% on average and was increasing by 2.3% per week (p<0.001). After social distancing, the conversion rate was 6.7% on average, and started to decrease by 4.2% per week (p<0.001). After mandatory masks, the conversion rate was 2.2% on average but has started to increase slowly by 0.9% per week (p<0.001;see figure 1). These findings do support decrease in conversion rate amongst New Yorkers who presented for endoscopy with the implementation of social distancing and mandatory masking. We believe the slow but significant increase in conversion rates by the end of May reflects the relative loosening in social distancing in New York City.(Figure Presented)