ABSTRACT
Based on the meteorological forecast data from the National Meteorological Bureau, this study developed an AERMOD-based pollution forecasting model for iron and steel plants, simulated air quality impacts of a typical iron and steel plant located in Hebei Province during the controlled period（from February to March in 2020） and the uncontrolled period（from April to October in 2020） of the COVID-19 epidemic, and validated the model with real monitoring air quality data. In case of adverse wind direction, the results showed that the average contribution of SO2, NOx and PM10 from the plant to three state-controlled monitoring stations were 20.19～33.81%, 17.49～23.46% and 2.02～2.69% respectively during the controlled period, and 13.43～21.01%, 11.09～20.92% and 1.20～2.22% during the uncontrolled period. The correlation coefficients between the forecast values of SO2, NOx and PM10 emission of the plant and the real monitoring values of the three state-controlled monitoring stations were higher in the controlled period（the highest values are 0.43,0.48 and 0.29, respectively, at individual monitoring station） compared with the uncontrolled period（the highest values are 0.42,0.39 and 0.07, respectively） due to the less interference from other anthropogenic emission sources during the controlled period.
ABSTRACT
Background and objective: The outbreak of COVID-19 has become a global health concern. In this study, we evaluate the effectiveness and safety of convalescent plasma therapy in patients with severe and critically ill COVID-19. Methods: Sixteen COVID-19 patients received transfusion of anti-COVID-19 antibody-positive convalescent plasma. The main outcome was time for viral nucleic acid amplification (NAA) test turning negative. Clinical laboratory parameters were measured at the baseline (d0) before plasma transfusion, and day 1 (d1), day 3 (d3) after transfusion as well. Results: Among the 16 patients, 10 of them had a consistently positive result of viral NAA test before convalescent plasma transfusion. Eight patients (8/10) became negative from day 2 to day 8 after transfusion. Severe patients showed a shorter time for NAA test turning negative after transfusion (mean rank 2.17 vs 5.90, P = 0.036). Two critically ill patients transfused plasma with lower antibody level remained a positive result of NAA test. CRP level demonstrated a decline 1 day after convalescent plasma treatment, compared with the baseline (P = 0.017). No adverse events were observed during convalescent plasma transfusion. Conclusions: Viral NAA test of most patients with COVID-19 who received convalescent plasma transfusion turned negative on the 2nd to 8th days after transfusion, and the negative time of severe patients was shorter than that of critically ill patients.