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Abstract The COVID-19 epidemic discovered and reported at the end of December 2019 and began spreading rapidly around the world. The impact of the COVID-19 event on the trip intensity, AQI (air quality index), and air pollutants, including PM2.5, PM10, SO2, CO, NO2, and O3 in Shenzhen, Guangzhou, and Foshan (the so-called ‘three cities’) from January 12 to March 27, in 2019 and 2020, are compared and discussed. In 2020, the combined trip intensity in the three cities ranged between 0.73 and 5.54 and averaged 2.57, which was 28.4% lower than that in 2019. In terms of the combined AQIs for the three cities, from January 12 to March 26, 2020, the daily AQIs ranged between 21.0 and 121.3 and averaged 56.4, which was 16.0% lower than that in 2019. The average AQIs in order were Guangzhou (57.5) > Foshan (54.1) > Shenzhen (44.1). In 2019, the distribution proportions of the six AQI classes were 45.2%, 50.4%, 4.40%, 0%, 0%, and 0%, respectively, while those in 2020 were 62.7%, 37.3%, 0%, 0%, 0% and 0%, respectively. For the combined data for the three cities, on the top five days with the highest AQIs during the epidemic period, the average concentrations of PM2.5, PM10, SO2, CO, NO2, and O3 were 76.4 µg m–3, 113.4 µg m–3, 5.14 ppb, 0.88 ppm, 36.5 ppb and 55.5 ppb, which were 55.2%, 49.4%, 55.1%, 30.0%, 45.1% and 15.5% lower than those during the non-epidemic period (from January 12 to March 27, 2017–2019). The above results revealed that the comprehensive strict epidemic prevention and control actions reduced trip intensity and improved the air quality significantly.

Abstract The effects of 9 precipitation events in Suzhou City in Anhui Province, China, on the air quality index (AQI), PM2.5, and dry deposition flux of PCDD/Fs (polydibenzo-p-dioxins and polydibenzofurans) were investigated. A total of 7 precipitation events were positive contributes to the reduction of AQI; among them, the AQI were between 23 and 216, with an average of 75, the PM2.5 concentrations were between 5.0 and 169 µg m−3, with an average of 25 µg m−3, while the total- PCDD/F-TEQ dry deposition flux ranged from 149 to 1034 pg WHO2005-TEQ m−2 day−1 and averaged 315 pg WHO2005-TEQ m−2 day−1. By comparing the average AQI and PM2.5, respectively, during and after rainfall with that before rainfall, the results indicated that the average reduction fractions of AQI were 26% and 44%, respectively, while those of PM2.5 were 58% and 43%. In addition, the effect of precipitation on the average reduction fraction of total PCDD/F-TEQ dry deposition flux was 31%. However, in the other 2 AQI elevation events, the AQI were between 23 and 100, and averaged 51; when comparing the average AQI and PM2.5 concentrations, during and after the rain with that before the rain, the increases in AQI were 42% and 49%, respectively, while the increases in PM2.5 concentration were 26% and 29%, respectively. The above results show that, on the whole, rain and snow improved the air quality. This is because rainwater removes particles or dissolved gaseous pollutants from the atmosphere and brings aerosols to the ground. However, in some cases, the increase of source emissions and atmospheric vertical convection, the effect of precipitation or air humidity increased the AQI and elevated the concentration of PM2.5, and dry deposition flux of PCDD/Fs. The results of this study provide useful information for both scientific communities and air quality management.

Abstract This study investigated the AQI (air quality index), atmospheric pollutants (PM2.5, NO2, and O3), and dry deposition of PCDD/Fs in Chengdu and Chongqing, near southwest China from 2020 to 2021. The results showed that the implementation of strict epidemic prevention action led to a significant improvement in the air quality in 2020. However, the air quality index increased again in 2021 as the economic activity was recovered. In February 2020, at the height of the epidemic, the monthly average PM2.5 and NO2 concentrations were estimated as 50.9 µg m–3 and 21.2 ppb, respectively in in Chengdu, and 48.9 µg m–3 and 22.9 ppb, respectively in Chongqing. In February 2021, when the economy was returned to normal, the monthly average PM2.5 and NO2 concentrations were 60.3 µg m–3 and 36.2 ppb respectively in Chengdu and 52.4 µg m–3 and 35.1 ppb, respectively in Chongqing. In addition, since O3 concentrations were influenced by the VOCs–NOx ratio, the reduction of NOx emissions and the increase of VOC emissions during the epidemic control period caused a change in the VOCs–NOx ratio, and thus leading to an increase in O3 concentrations. The monthly average concentration of O3 from March 2021 to May 2021 was significantly lower than that of 2020. Furthermore, the dry deposition flux of PCDD/Fs also changed in the period before and after the epidemic. The dry deposition flux of PCDD/Fs in 2021 was significantly higher than that of 2020, which was associated with the fuel consumption of various industrial plants. This study indeed provided useful information for the contribution of scientific communities and important data bank for the future air quality control.

Abstract This study mainly involved conducting an atmospheric sensitivity analysis of the dry deposition and PM2.5-bound content of total PCDD/Fs-WHO2005-TEQ, respectively. The results for Fuzhou and Xiamen cities showed that the total PCDD/F mass concentration was the factor most positively correlated to the dry deposition flux: When ΔP/P ranged from –50% to 0%, ΔS/S ranged from −66.0% to 0%, but when ΔP/P increased from 0% to +50%, ΔS/S increased from 0% to +66.0%, respectively. The second factor positively correlated with the deposition flux was the PM2.5 concentration: When ΔP/P ranged from −50% to 0%, ΔS/S ranged from −63.3% to 0%; when ΔP/P increased from 0% to +50% and +100%, ΔS/S ranged from 0% to +20.8 and −0.9%, respectively. Ambient air temperature was found to be less sensitive to dry deposition fluxes in total PCDD/Fs-WHO2005-TEQ: When ΔP/P ranged from −50% to −17% and 0%, ΔS/S ranged from −17.0% to +5.6% and 0%; when ΔP/P increased from 0% to +50%, ΔS/S increased from 0% to −84.5%, respectively. The sensitivity analysis for PM2.5-bound total PCDD/Fs-WHO2005-TEQ content had similar results to those for dry deposition flux. In addition, in 2018, 2019, and 2020, the annual average PM2.5-bound total PCDD/Fs-WHO2005-TEQ content at Fuzhou and Xiamen was 0.430, 0.127, 0.303, and 0.426 ng-WHO2005-TEQ g−1 in the spring, summer, autumn and winter, respectively, which showed that summer had the lowest content, while spring and winter had the highest. The results of this study provided useful information for gaining a deeper understanding of both dry deposition and particle-bound of PCDD/Fs in the ambient air.

Abstract Wet deposition is an important mechanism for removing air pollutants from the atmosphere. The total PCDD/Fs-WHO2005-TEQ wet deposition from 2018–2020 was investigated for Beijing and Tianjin City in this study. In addition, the gas-particle partitioning of wet deposition, the total PCDD/Fs-WHO2005-TEQ concentrations in the rain, the PM2.5-bound total PCDD/Fs-WHO2005-TEQ content, and the PM2.5 concentration were also studied for Beijing and Tianjin City, respectively. Between 2018 to 2020, as a whole, the average seasonal variations in PCDD/F wet deposition fluxes in spring, summer, fall, and winter were 50.50, 41.47, 23.03 and 16.76 pg WHO2005-TEQ m–2 month–1, respectively, while in Tianjin, they were 35.30, 42.40, 13.37, and 14.77 pg WHO2005-TEQ m–2 month–1, respectively. Because the two cities have more rainfall in spring and summer than they do in fall and winter, rainfall has a significant influence on the wet deposition flux. In regard to PCDD/Fs-WHO2005-TEQ in the rain, in Beijing, the average total PCDD/Fs-WHO2005-TEQ concentration in the rain in spring, summer, fall, and winter were 1.70, 0.39, 1.42, and 1.52 pg WHO2005-TEQ L–1, respectively, while those in Tianjin, were 1.73, 0.42, 1.35, and 1.88 pg WHO2005-TEQ L–1, respectively. The above results show that the total PCDD/Fs-WHO2005-TEQ concentrations in the rain are significantly lower in summer, which is mainly due to the fact that in summer, the total PCDD/Fs-WHO2005-TEQ concentrations in the air are lower, and the proportion of the gas phase is increased. When the total PCDD/Fs-WHO2005-TEQ concentrations in the air are washed away by a heavy rainfall, the PCDD/F concentrations are diluted.

Abstract In this study, the atmospheric total-PCDD/Fs-WHO2005-TEQ concentrations, gas-particle partitioning, PM2.5 concentration, PM2.5-bound total PCDD/Fs-WHO2005-TEQ content and dry deposition flux in Shanghai and Nanjing were investigated from 2018–2020. In Shanghai, the total PCDD/Fs-WHO2005-TEQ concentration dropped from 0.0291 pg-WHO2005-TEQ m−3 from 2018–2019 to 0.0250 pg-WHO2005-TEQ m−3 in 2020, while in Nanjing, it dropped from 0.0423 pg-WHO2005-TEQ m−3 to 0.0338 pg-WHO2005-TEQ m−3. The average concentrations of PCDD/Fs-WHO2005-TEQ in spring and winter in Shanghai and Nanjing were 47.6% and 53.8% higher than those in summer, respectively. From 2018–2019, the average particle phase fractions of total-PCDD/Fs-WHO2005-TEQ in Shanghai and Nanjing were 50.3% and 57.5%, respectively, while in 2020, they were 47.8% and 55.1%, respectively. From 2018–2019, the average PM2.5-bound total PCDD/Fs-WHO2005-TEQ content was 0.342 and 0.493 ng-WHO2005-TEQ g−1 in Shanghai and Nanjing, respectively, while in 2020, it was 0.312 and 0.489 ng-WHO2005-TEQ g−1, respectively. In Shanghai and Nanjing, the average PM2.5-bound total PCDD/Fs-WHO2005-TEQ content in spring and winter was 77.5% and 73.2% higher than that in summer, respectively. From 2018–2019, the dry deposition flux of total-PCDD/Fs-WHO2005-TEQ was 316.3 and 460.5 pg WHO2005-TEQ m−2 month−1 in Shanghai and Nanjing, respectively, while in 2020, it was 272.5 and 368.4 pg WHO2005-TEQ m−2 month−1, respectively. The average dry deposition flux of total-PCDD/Fs-WHO2005-TEQ in spring and winter was 47.6% and 53.8% higher than that summer in Shanghai and Nanjing, respectively. The above results indicate that COVID-19 in 2020 had a positive effect on air quality improvement in PCDD/Fs. On average, more than 98.88% of the total PCDD/Fs-WHO2005-TEQ dry deposition flux was primarily contributed by the particle phase. This was attributed to the fact that dry deposition of particle phase PCDD/Fs was mainly due to gravitational settling accompanied by higher dry deposition velocities, while the gas phase PCDD/Fs were deposited mostly by diffusion at a lower dry deposition velocity.

Abstract This study investigated the AQI (air quality index) and atmospheric pollutants including PM2.5, PM10, CO, SO2, NO2 and O3 in Chongqing, Luzhou and Chengdu from 2017 to 2019. In addition, the impacts of the COVID-19 event on the air quality in the three cities in 2020 were compared and discussed. For the combined AQIs for the three cities, in spring, the daily AQIs ranged between 25 and 182 and averaged 72.1. In summer, the daily AQIs ranged between 24 and 206 and averaged 77.5. In autumn, the daily AQIs ranged between 22 and 170 and averaged 61.1, and in winter, the daily AQIs ranged between 28 and 375 and averaged 99.6. The distributions of the six AQI classes in spring were 3%, 94%, 3%, 0%, 0%, and 0%; in summer, they were 11%, 74%, 15%, 0%, 0% and 0%; in autumn, they were 29%, 70%, 1%, 0%, 0%, and 0%, and in winter, they were 1%, 52%, 44%, 3%, 0%, and 0%, respectively. The average AQIs, in order, were Chengdu (85.4) > Chongqing (73.8) > Luzhou (73.2). Both the highest AQIs and PM2.5 (as the major indicatory air pollutant) occurred mainly in the low temperature season (January, December, and February), while O3 was the main air pollutant in June and August when the weather was hot. In February 2020, during the epidemic prevention and control actions taken in response to COVID-19 for the three cities, the combined AQIs for the top five days with the highest AQIs in February 2020 was 79.4, which was 23.6% lower than that from 2017–2019 (AQI = 100.7), and the average concentrations of PM2.5, PM10, SO2, CO, and NO2 were 89.4 µg m−3, 106 µg m−3, 2.31 ppb, 0.72 ppm, and 12.3 ppb, respectively, and were 17.9%, 30.8%, 83.8%, 19.8%, and 62.1%, lower than those in February 2017–2019. However, the average O3 concentration (31.8 ppb) in February 2020 rather than decreasing, increased by 6.2%. This is because a lower NO2 concentration hindered the NO + O3 reaction and led to increase O3 concentration in the ambient air.

Abstract Both the air quality index (AQI) and indicatory air pollutants of Anqing, Hefei, and Suzhou near central China from 2017 to 2019, and the impact of COVID-19 epidemic prevention and control actions on air quality were investigated. The combined data for the three cities from 2017 to 2019 indicated that the lowest AQI (averaged 78.1) occurred in the summer season, for which the AQI proportions for classes I, II, III, IV, V, and VI were 25.6%, 49.9%, 21.9%, 2.7%, 0%, and 0%, respectively. The highest (AQI average of 112.6) was in winter, for which the proportions were 7.4%, 39.5%, 33.3%, 12.5%, 7.2%, and 0.1%, respectively. PM2.5, PM10, and NO2 in order were the most important indicatory air pollutants for AQI classes IV, V, and VI, which all prevailed in winter and spring, while O3 was the indicatory air pollutant that occurred most in summer. The COVID-19 event, which triggered global attention, broke out at the end of 2019. This study also investigated and compared the air quality levels in the three cities from January to March 2017–2019 with those in 2020. The results showed that during February 2020, in the three cities, the average ambient air concentrations of PM2.5, PM10, SO2, CO, and NO2 were 41.9 µg m−3, 50.1 µg m−3, 2.18 ppb, 0.48 ppm, and 8.97 ppb, and were 46.5%, 48.9%, 52.5%, 36.2%, and 52.8%, respectively, lower than those in the same month in 2017–2019, respectively. However, the O3 average concentration (80.6 ppb) did not show significant fluctuations and even slightly increased by 3.6%. This is because a lower concentration of NO2 resulted in constraints on the reaction of NO + O3, so the O3 level could not be effectively further reduced. In addition, this study also analyzed and compared the five highest daily AQIs from February 2017–2019 with those of 2020 for the three cities. The mean AQI for the 5 days with the highest daily AQI (averaged 122.6) in February 2020 was 45.1% lower than that for February 2017–2019 (averaging 223.2), and the indicatory air pollutant was always PM2.5, which decreased by 46.7% (from 173.6 to 92.6 µg m−3). It is clear that during the COVID-19 epidemic prevention and control action periods, the air quality near central China improved significantly.

Aims: Rheumatoid arthritis (RA) is associated with cardiovascular disease (CVD), but the influence of CVD risk factors on RA outcomes is limited. We examined if CVD risk factors alone are associated with RA disease activity and disability. Methods: We performed a cross-sectional analysis of participants in the Ontario Best Practices Research Initiative, RA registry. Patients were categorized into mutually exclusive CVD categories: (1) No established CVD and no CVD risk factors; (2) CVD risk factors only including ⩾1 of hypertension, dyslipidemia, diabetes, or smoking; or (3) history of established CVD event. Multivariable regression analyses examined the effect of CVD status on Disease Activity Score 28 (DAS28-ESR), Clinical Disease Activity Index (CDAI), and Health Assessment Questionnaire Disability Index (HAQ-DI) scores at baseline. Results: Of 2033 patients, 50% had at least 1 CVD risk factor, even in the absence of established CVD. The presence of ⩾1 CVD risk factor was independently associated with higher CDAI [β coefficient 1.59, 95% confidence interval (CI) 0.29–2.90, p = 0.02], DAS28-ESR (β coefficient 0.20, 95% CI 0.06–0.34, p = 0.01) and HAQ-DI scores (β coefficient 0.15, 95% CI 0.08–0.22, p 1 CVD risk factor was associated with higher disease activity and disability, compared with having one or no CVD risk factors. Conclusion: CVD risk factors alone, or in combination, are associated with higher disease activity and disability in RA. This emphasizes the importance of risk factor recognition and management, not only to prevent CVD, but also to improve potential RA outcomes.

BackgroundTo establish, characterize and elucidate potential mechanisms of acquired bleomycin (BLM) resistance using human cancer cell lines. Seven BLM-resistant cell lines were established by exposure to escalating BLM concentrations over a period of 16-24 months. IC50 values and cell doubling times were quantified using a real time cytotoxicity assay. COMET and γ-H2AX assays, cell cycle analysis, and apoptosis assessment further investigated the mechanisms of BLM resistance in these cell lines.ResultsCompared with parental cell lines, real time cytotoxicity assays revealed 7 to 49 fold increases in IC50 and a mean doubling time increase of 147 % (range 64 %-352%) in BLM-resistant sub-clones (pConclusionBleomycin resistance may be associated with reduced DNA damage after bleomycin exposure, resulting in reduced G2/M arrest, and reduced apoptosis.

Natural organic matter such as guar and humus are recalcitrant to conventional pretreatment technologies and can potentially foul processes such as membranes during water treatment. An innovative method of using synthetic layered double hydroxides (LDH) was investigated for removing common natural organic matter in the form of guar gum (GG) and humic acid (HA) from water. Adsorption isotherms were evaluated with Langmuir and Freundlich models. Results show the affinity of GG and HA to LDH to be 11.31 and 9.33mgg-1 LDH, respectively. Kinetic isotherms indicate that the sorbing rates of LDH to GG and HA increase with initial GG and HA concentrations, fitting a pseudo-second order model. This study demonstrate that LDH may be an effective material in removing GG and HA from waters and offer an alternative to conventional pretreatment technologies for the mitigation fouling of membrane and other systems in water treatment. [ABSTRACT FROM AUTHOR]