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This study used the officially released data by the Chinese air quality monitoring network to analyze the pollution characteristics of six air pollutants (PM2.5, PM10, SO2, NO2, CO, and O3) for 29 cities in the Central Plains Economic Zone (CPEZ; China) in 2015. During 2015, serious particulate matter (PM) pollution often occurred, and the concentrations of PM2.5 and PM10 were 77 μg m−3 and 128 μg m−3, respectively. Air pollutants were at higher concentrations in the northern cities than those in the southern region of the CPEZ, and the correlation among the cities indicated that there was regional pollution in CPEZ. Generally, PM, SO2, NO2, and CO showed similar seasonal characteristics and the highest and lowest concentrations appeared in winter and summer, respectively. In addition, we used the HYSPLIT model and trajStat model to identify the potential source contribution function and concentration-weighted trajectory of Zhengzhou, the central city of CPEZ. More serious air pollution occurred when air masses were transported from the west of the CPEZ. Shaanxi Province, Hubei Province, Anhui Province and the northwest of the CPEZ were found to be the main exogenous sources of total PM with contributions of > 100 μg m−3 PM2.5 and > 180 μg m−3 PM10. Therefore, the concentrations of PM in 2015 at Zhengzhou were probably influenced by both long-distance transmission and local emissions.

Bioaerosols are an important component of particulate matter in the atmosphere and are harmful to human health. In this study, the concentration, size distribution, and factors influencing culturable airborne bacteria and fungi in the atmosphere were investigated using a six-stage impactor device in the city of Xinxiang, China, during the winter season. The results revealed that the concentration of culturable airborne bacteria and fungi varied significantly during the sampling period: 4595 ± 3410 and 6358 ± 5032 CFU/m3, respectively. The particle sizes of the bioaerosols were mainly within stage V (1.1-2.1 μm), and fine particulate matter accounted for 45.9% ± 18.9% of airborne bacteria and 52.0% ± 18.5% of airborne fungi, respectively. With the deterioration of air quality, the concentration of airborne fungi gradually increased, and that of airborne bacteria increased when the air quality index was lower than 200 and decreased when it was higher than 200. With respect to the diurnal variation pattern of bioaerosol concentration, the highest and lowest concentrations were registered at night and noon, respectively, probably because of changes in ultraviolet radiation intensity. Bioaerosol concentration positively correlated with humidity, concentration of PM2.5, PM10, SO2, and NO2 and negatively correlated with O3 concentration. The risk of exposure of humans to the airborne bacteria was primarily associated with the respiratory inhalation pathway, and the risk of skin exposure was negligible. These results should improve our understanding of the threat of bioaerosols to public health.

The degradation of diclofenac sodium (DCF) in pre-magnetization Fe0/persulfate (Pre-Fe0/PS) and Fe0/PS systems were studied in detail in this study. The influencing operational conditions (initial PS dosage, Fe0 dosage, and pH) were studied for their effects on the DCF degradation. The removal rate constant for DCF by the Pre-Fe0/PS system was 2.1–6.2 times higher than that of the Fe0/PS system. A higher TOC removal efficiency (81.5%) was observed during the mineralization of DCF in the Pre-Fe0/PS process than that of the Fe0/PS process (70%). The results of electron paramagnetic resonance (EPR) confirmed that the Pre-Fe0/PS system could produce much more •OH and SO4−• at a faster rate than the Fe0/PS system. Moreover, the degradation mechanism of DCF by the Pre-Fe0/PS process was elucidated. This work would provide a perspective on the Pre-Fe0/PS process for efficient degradation of DCF, exhibiting advantages to removing DCF, such as broaden the range of working pH and reduce the amount of chemicals. So, it is an efficient and potential method to remove DCF from wastewater by the Pre-Fe0/PS process.

The levels, spatial variation, congener profiles, impact factors, and ecological risk of polychlorinated biphenyls (PCBs) in the sediment from the Yellow River of Henan section, China, were investigated in this paper. Total concentration of 31 PCBs and seven indicator PCBs varied from ND to 1015 pg g-1 and ND to 423 pg g-1, respectively. Compared with other aquatic environments around China, PCB levels in the studied area were relatively low. Spatial variations revealed that tributaries possessed higher PCB levels, in comparison to mainstream, which acted as input sources of PCBs in the mainstream. The homolog profiles were dominated by lighter PCBs (Tri-PentaCBs), contributing above 70% of total PCBs. Correlation analysis between PCB concentrations and total organic carbon indicated that local input or atmospheric deposition was the primary controls of spatial variation of PCBs. According to simple sediment quality guidelines (SQG), the risks posed by PCBs in the sediments might be negligible.

The pollution characteristics of PM2.5 and correlation analysis with meteorological parameters in Xinxiang during the Shanghai Cooperation Organization Prime Ministers’ Meeting were investigated. During the whole meeting, nine PM2.5 samples were collected at a suburban site of Xinxiang, and the average concentration of PM2.5 was 122.28 μg m−3. NO3 −, NH4 +, SO4 2− accounted for 56.8% of the total water-soluble ions. In addition, with an exception of Cl−, all of water-soluble ions decreased during the meeting. Total concentrations of crustal elements ranged from 6.53 to 185.86 μg m−3, with an average concentration of 52.51 μg m−3, which accounted for 82.5% of total elements. The concentrations of organic carbon and elemental carbon were 7.71 and 1.52 μg m−3, respectively, lower than those before and after the meeting. It is indicated that during the meeting, limiting motor vehicles is to reduce exhaust emissions, delay heating is to reduce the fossil fuel combustion, and other measures are to reduce the concentration of PM2.5. The directly dispersing by mixing layer height increase and the indirectly reducing the formation of secondary aerosol by low relative humidity, and these are the only two key removing mechanisms of PM2.5 in Xinxiang during the meeting.

Seventeen PM2.5 samples were collected at Xinxiang during winter in 2014. Nine water-soluble ions, 19 trace elements and eight fractions of carbonaceous species in PM2.5 were analyzed. PM2.5 concentrations and elements species during different periods with different pollution situations were compared. The threat of heavy metals in PM2.5 was assessed using incremental lifetime cancer risk. During the whole period, serious regional haze pollution persisted, and the averaged concentration of PM2.5 was 168.5 μg m−3, with 88.2 % of the daily samples exhibiting higher PM2.5 concentrations than the national air quality standard II. The high NO3 −/SO4 2− ratio suggested that vehicular exhaust made an important contribution to atmospheric pollution. All of organic carbon and elemental carbon ratios in this study were above 2.0 for PM2.5, which might reflect the combined contributions from coal combustion, motor vehicle exhaust and biomass burning. Mean 96-h backward trajectory clusters indicated that more serious air pollution occurred when air masses transported from the Hebei, Shanxi and Zhengzhou. The concentrations of the water-soluble ions and trace elements on haze days were 2 and 1.8 times of those on clear days. The heavy metals in PM2.5 might not cause non-cancerous health issues by exposure through the human respiratory system. However, lifetime cancer risks of heavy metals obviously exceeded the threshold (10−6) and might have a cancer risk for residents in Xinxiang. This study provided detailed composition data and comprehensive analysis of PM2.5 during the serious haze pollution period and their potential impact on human health in Xinxiang.