Short-term Effects Of PM_2.5 And O₃ Pollution On The Acute Nasopharyngitis In Four Cities Of Guangdong,China

OBJECTIVE:To investigate the short-term effects of fine particulate matter(PM_2.5)and surface ozone（O₃）on acute nasopharyngitis.METHODS:A cross-sectional survey was conducted in 10 communities in four cities of Guangdong province from 2015 to 2016.Standardized questionnaires were used to record the prevalence of acute nasopharyngitis in the first two weeks,as well as some important covariables.The ground monitoring data of air pollutants and meteorological factors in the communities surveyed were collected,and the air pollution exposure of the respondents was assessed according to the date of investigation and the date of illness.The relationship between short-term air pollution exposure and acute nasopharyngitis was quantitatively analyzed by means of two-level logistic regression model.The lag patterns of PM_2.5.5 and O₃before and after adjustment of potential confounding factors were compared to estimate the potential delay and cumulative correlation.Sex,age,level of education,household income and effect modification of occupational pollution exposure were analyzed by stratified analysis,and sensitivity analysis was carried out to test the robustness of the results.RESULTS:The results showed that there was a significant positive correlation between acute nasopharyngitis and short-term exposure to PM_2.5.5 and O₃（P<0.05）and increased significantly after adjusting for confounding factors.There was a positive correlation between PM_2.5.5 and single-day and multi-day lag effects in acute nasopharyngitis,and reached the peak in lag2and lag02.When the concentration of PM_2.5.5 was increased by 10μg/m³,the OR value of single pollutant model at lag2 day was 1.12（95%confidence interval（CI）:1.08,1.16）,and the ratio adjusted by confounding factor was higher（adjusted OR=1.20;95%CI:1.16,1.25）.Moving average concentrations from lag01 to lag06 also have a significant impact.For example,the OR value of the single factor model in lag02 is 1.09（95%CI:1.05,1.14）,and the adjusted OR value is 1.18（95%CI:1.13,1.23）.The correlation between O₃ and acute nasopharyngitis was generally consistent with the trend of PM_2.5.After adjusting for confounding factors,the correlation between O₃ and acute nasopharyngitis was more significant,reaching the peak of lag4（OR=1.08,95%CI:1.05,1.11）and lag06（OR=1.08,95%CI:1.04,1.13）,respectively.CONCLUSIONS:The fine particle pollutants still exceed the national limit,but their concentration decreases year by year,and the ozone pollution concentration increases gradually.It is suggested that short-term exposure to PM_2.5.5 and O₃may be an important risk factor for acute nasopharyngitis.The concentration of air pollutants in the environment should be continuously monitored and scientific and reasonable emission standards should be established.