Characteristics, Secondary Formation and Regional Contributions of PM2.5 Pollution in Jinan during Winter

Air pollution is an increasing threat to human health in China. In this study, daily PM10 and PM2.5 samples were collected simultaneously at the Jinan Environmental Monitoring Station (EMS)in Jinan, China from 15 November 2016 to 15 March 2017. The aim of this work was to improve the understanding of the characteristics and sources of air particles and determine different levels of PM2.5 pollution and its constituent elements, water-soluble ions and carbonaceous species. Nitrate (NO3−), organic materials (OM) and sulfate (SO42−) were identified as the three main components of PM2.5 pollution. With increasing pollution level, the contributions of SO42−, NO3− and NH4+ increased at greater rates, unlike that of OM. The proportion of SO42− exceeded that of NO3− and became predominant in severe PM2.5 pollution (SP; 250 μg m−3 ≤ PM2.5 ≤ 500 μg m−3). This work demonstrates that SO42− has a dominant role in SP level and, consequently, requires greater research attention. It is demonstrated that relative humidity (RH) enhances the rate of sulfate formation more than that of nitrate. Therefore, under the current Chinese emergency response measures, it is necessary to further reduce emissions of SO2 and NO2. Four clusters of backward trajectories identified dominant pollution vectors originating from highly industrialized areas that exacerbate the poor air quality in Jinan. It is, therefore, necessary to undertake regional control measures to reduce pollutant emissions.

Association of School Residential PM2.5 with Childhood High Blood Pressure: Results from an Observational Study in 6 Cities in China

Objective: To investigate the association of long-term PM2.5 exposure with blood pressure (BP) outcomes in children aged 6–18 years, and to examine the population attributable risk (PAR) of PM2.5 exposure. Methods: A total of 53,289 participants aged 6–18 years with full record of age, sex, BP, height, and local PM2.5 exposure from a cross-sectional survey conducted in 6 cities of China in 2013 were involved in the present study. PM2.5 data from 18 January 2013 to 31 December 2013 were obtained from the nearest environmental monitoring station for each selected school. Two-level linear and logistic regression models were used to evaluate the influence of PM2.5 on children’s BP, and PAR was calculated in each sex and age group. Results: Participants had a mean age of 10.8 (standard deviation: 3.4) years at enrollment, 51.7% of them were boys. U-shaped trends along with increased PM2.5 concentration were found for both systolic blood pressure (SBP) and diastolic blood pressure (DBP), with the thresholds of 57.8 and 65.0 μg/m3, respectively. Both increased annual mean of PM2.5 concentration and ratio of polluted days were associated with increased BP levels and high blood pressure (HBP), with effect estimates for BP ranging from 2.80 (95% CI: −0.51, 6.11) mmHg to 5.78 (95% CI: 2.32, 9.25) mmHg for SBP and from 0.77 (95% CI: −1.98, 3.52) mmHg to 2.66 (−0.35, 5.66) mmHg for DBP, and the odds ratios for HBP from 1.21 (0.43, 3.38) to 1.92 (0.65, 5.67) in the highest vs. the lowest quartiles. Overall, 1.16% of HBP in our participants could be attributed to increased annual mean of PM2.5 concentration, while 2.82% could be attributed to increased ratio of polluted days. These proportions increased with age. Conclusions: The association between long-term PM2.5 exposure and BP values appeared to be U-shaped in Chinese children aged 6–18 years, and increased PM2.5 exposure was associated with higher risk of HBP.