| With the rapid economic development,population expansion and urbanization,Xinxiang has experienced ever-increasing energy consumption and sharp increase of motor vehicles,where the fine particulate matter has become an important problem of atmospheric pollution.It is very necessary to study how to control the air pollution in Xinxiang and to make the corresponding pollution control measure.However,the detailed statistical characteristics of ambient PM2.5 concentration in Xinxiang are limited.In this study,the concentrations of air pollutants in Xinxiang were collected,and the seasonal various were analyzed.The air quality of Xinxiang was evaluated.Meanwhile,we present the results of the major chemical components of PM2.5 in 2015 at an urban site in Xinxiang.Compared the chemical properties in different seasons,and analyzed the main source of PM2.5 and calculate the cancer risks of PM2.5 during the whole study period.The pollution characteristics of typical pollution period in the whole year were discussed,and studied the effect of emission reduction measures on atmospheric pollutants during the Shanghai Cooperation Organization Prime Ministers' Meeting?SCOPMM?.In addition,the influence of meteorological factors on PM2.5 concentration in Xinxiang was analyzed.The results of this study are useful to understand the characteristics of air pollution and the characteristics of PM2.5 in Xinxiang and provide a scientific basis for the prevention and control of PM2.5 pollution.The results showed that:1??1?In Xinxiang,except SO2 and O3,others pollutants were higher than threshold in the China Ambient Air Quality Standards?GB3095-2012?Grate I and Grate II.In winter,the prevailing wind was from the north or northeast China,and the wind could carry more polluted air mass.In addition,the unfavorable weather conditions for air pollution dilution and dispersion.Meanwhile,PM2.5 was highly correlated with PM10 ,SO2,NO2 and CO in all cities,reflecting the common origin of these species.?2?The annual average AQI was 130 in Xinxiang,which belongs Grate III.The level of pollution on human health has a certain amount of harm.In 2015,PM2.5 was the highest frequency as primary pollutants in Xinxiang,followed by PM10 ,O3 and NO2.2??1?For the water-soluble ions analyzed,the combination of SO42-,NO3-and NH4+,which could be regarded as secondary inorganic aerosols,constituted 70% of the total ionic concentrations.Thetotal concentrations of the crustal elements?Al,Ca,Fe,Mg,K,and Na?accounted for 32% to 94% of the total elements.The average concentrations of elemental carbon?EC?and organic carbon?OC?were 1.2±0.8and 4.6±3.6 ?g/m3.The maximum-to-minimum ratios were 36.8 for OC and 16.2 for EC,which indicated that the variability of OC was greater than that of EC.The concentrations of SO42-and NO3-were the highest in winter and the concentration of Cl-increased,which might be attributed to temperature and coal combustion.The increased concentration of NH4+ was observed in autumn,which was attributed to the more frequent biomass burning activities.The highest concentration of K+ was also observed in autumn and increased in September,which was caused by straw burning.The concentrations of Mn,Ti,Mg,Na,Li,Cu,Ni,Co,Cr and Pb were not significantly seasonal variation,suggesting that the emission sources were relatively stable,which were less affected by seasonal variation.The concentrations of OC and EC had similar seasonal patterns of waxing in winter and waning in summer.The OC/EC ratio mostly fell within the range of 2-5,which indicated that the presence of secondary organic matter.?2?In this study,the correlations between PM2.5 and meteorological factors were high.We also calculated the PM2.5 -MLH-relative humidity-temperature-wind speed regression equation.The influence of wind speed on PM2.5 was obviously greater than that of mixing layer height and relative humidity.?NH4?2SO4 had the largest contribution to bext.During winter,contribution of OM was the largest contributor to visibility degradation.?3?According to the EF,Fe,Li,Na,Mg,Al,K,Ca and Sr were mainly derived from natural sources such as soil dust.Co and Mn might be a source of anthropogenic and soil sources.Pb,Cr,Ni,Cu,Zn,As,Cd and V came from anthropogenic pollution.Meanwhile,these elements are tracer elements for motor vehicles,industrial production and coal burning,and reflects the impact of industrial,motor vehicles,coal burning on air quality.Analysis using tracer and PCA/MLR showed that vehicle exhausts was the most important source of PM2.5 .?4?Health risk assessment revealed that non-cancerous effects of heavy metals in PM2.5 occurred,and lifetime cancer risks of heavy metals obviously exceeded the threshold and might pose cancer risks for the residents in Xinxiang.3??1?The average concentration of PM2.5 was 111±54 ?g/m3 during the Spring Festival.Chemical species declined due to holiday effect with the exception of K,Fe,Mg,Al and K+,Cl-,which increased on Chinese New Year?CNY?'s Eve and lantern festival in 2015,indicating the injection of firework burning particles in certain short period.PM2.5 mass closure showed that secondary inorganicspecies were the dominant fractions of PM2.5 over the entire sampling.During the Spring Festival,burning source,including coal combustion,fireworks,fire crackers and biomass burning,was the most important source of PM2.5 ,which contributed 61% of PM2.5 over the whole period.Health risk assessment revealed that noncancerous effects of heavy metals in PM2.5 of Xinxiang were unlikely happened,while lifetime cancer risks of heavy metals obviously exceeded the threshold,which might have a cancer risk for residents in Xinxiang.?2?The PM2.5 concentration during the SCOPMM?December 14-16?were 44.5 ?g/m3,which was lower than average concentration in winter.It suggested that the pollution control measures during the meeting played an effective control on PM2.5 . |
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