Atmospheric hydrogen peroxide (H 2 O 2 ) plays an important role in sulfate formation. To explore the contribution of the H 2 O 2 oxidation pathway to atmospheric sulfate in winter in Beijing, three field campaigns of atmospheric H 2 O 2 measurements were conducted at an urban site (Beijing) and a rural site (Wangdu) during the winter in 2016, 2017, and 2018. The H 2 O 2 concentrations were usually around the detection limit (0.05 ppbv) during clean and severely polluted periods, whereas the highest H 2 O 2 concentration of 0.90 ppbv was observed during moderately polluted periods. Obvious increases in the concentration of H 2 O 2 could be observed after sunset at the urban site during each moderately polluted day, which was mainly attributed to transportation of H 2 O 2 -rich air from the rural areas in the south of Beijing. Coincident increases in the concentrations of H 2 O 2 and PM 2.5 were also observed during the day at high NO concentrations, implying that heterogeneous reactions might contribute to the formation of H 2 O 2 under polluted conditions. In addition, the contrast between urban and rural measurements also provides some support for the potential formation of H 2 O 2 from heterogeneous reactions. On the basis of the data measured in this study, sulfate formation through H 2 O 2 oxidation was found to be the dominant pathway rather than the NO 2 oxidation pathway.

ABO and Rh blood groups play a vital role in blood transfusion safety and clinical practice and are thought to be linked with disease susceptibility. The results from previous studies that focused on the association between blood groups and HBV infection remain controversial. China has the world's largest burden of HBV infection. We assessed the distribution of ABO/Rh blood groups in Chinese adults and examined the association between these groups and HBV infection. We did a nationwide cross-sectional study using data from a physical check-up programme from 31 provinces examined between 2010 and 2012. ELISA was used to test for HBsAg in serologic samples. Multivariable logistic regression was used to estimate aOR of the association between ABO and Rh blood groups and HBV infection. Among 3 827 125 participants, the proportion of participants with blood group A was highest (30.54%), followed by O (30.37%), B (29.42%) and AB (9.66%). A total of 38 907 (1.02%) were Rh-D negative. The prevalence of HBsAg in blood groups O, A, B and AB were 6.34%, 5.55%, 5.18% and 5.06%, respectively. HBsAg prevalence was 5.65% in Rh-D-positive and 3.96% in Rh-D-negative participants. After controlling for other potential risk factors, multivariate models showed that participants with blood group O (adjusted OR = 1.22, 95% CI: 1.20-1.25) were at higher risk of HBV infection compared with group AB. Rh-D-positive participants (adjusted OR = 1.44, 95% CI: 1.37-1.52) were at higher risk of HBV infection than Rh-D-negative participants. The associations between ABO/Rh blood groups and HBV infection were similar in subgroup analysis. The proportions of O, A, B and AB blood groups were approximately 3:3:3:1, and nearly 1 in 100 people was Rh-D negative among Chinese adults. Blood group O and Rh-D positivity were both associated with increased HBV infection. The risk of HBV infection and blood safety should be taken into consideration in clinical practice, especially when transfusing those with blood group O. Awareness and prevention of HBV infection is of particular importance for individuals with blood group O.