Association between Ambient Air Pollution and Outpatient Visits for Acute Bronchitis in a Chinese City

Objective To investigate the short-term association between outdoor air pollution and outpatient visits for acute bronchitis,which is a rare subject of research in the mainland of China.Methods A time-series analysis was conducted to examine the association of outdoor air pollutants with hospital outpatient visits in Shanghai by using two-year daily data（2010-2011）.Results Outdoor air pollution was found to be associated with an increased risk of outpatient visits for acute bronchitis in Shanghai.The effect estimates of air pollutants varied with the lag structures of the concentrations of the pollutants.For lag06,a 10 μg/m3 increase in the concentrations of PM10,SO2,and NO2 corresponded to 0.94%（95% CI：0.83%,1.05%）,11.12%（95% CI：10.76%,11.48%）,and 4.84%（95% CI：4.49%,5.18%） increases in hospital visits for acute bronchitis,respectively.These associations appeared to be stronger in females（P〈0.05）.Between-age differences were significant for SO2（P〈0.05）,and between-season differences were also significant for SO2（P〈0.05）.Conclusion Our analyses have provided the first evidence that the current air pollution level in China has an effect on acute bronchitis and that the rationale for further limiting air pollution levels in Shanghai should be strengthened.

Diurnal Temperature Range as a Novel Risk Factor for Sudden Infant Death

Objective To assess the relationship between diurnal temperature range （DTR） and sudden infant death （SID） between 2001 and 2004 in Shanghai,China.Methods We conducted a time‐stratified case‐crossover analysis to estimate the percent increase of SID associated with changes in DTR after adjustment for daily weather conditions （temperature and relative humidity） and outdoor air pollution.Results DTR was significantly associated with daily SID.An increase of 1 °C in the current‐day （L0） and in the 2‐day moving average （L01） DTR corresponds to a 1.56% （95% CI：0.97%,2.15%） and a 1.89% （95% CI：1.17%,2.60%） increase in SID,respectively.Conclusion An increased DTR was associated with an increased risk of SID in Shanghai.More studies are needed to understand the effect of DTR on infant deaths.

Association Between Diurnal Temperature Range and Respiratory Tract Infections

Objective This study aimed to assess the association between emergency-room visits for respiratory tract infection （RTI） with diurnal temperature range （DTR）, a weather parameter closely associated with urbanization and global climate change. Methods We conducted a semiparametric time-series analysis to estimate the percentage increase in emergency-room visits for RTI associated with changes in DTR after adjustment for daily weather conditions （temperature and relative humidity） and outdoor air pollution. Results DTR was significantly associated with daily emergency-room visits for RTI. An increase of 1 ~C in the current-day （LO） and in the 2-day moving average （L01） DTR corresponded to a 0.94% [95% confidence interval （CI）, 0.34%-1.55%] and 2.08% （95% CI, 1.24%-2.93%） increase in emergency-room visits for RTI, respectively. Conclusion DTR was associated with increased risk of RTI. More studies are needed to understand the impact of DTR on respiratory health.

Impact of Temperature on Mortality in Three Major Chinese Cities

Objective To study the relation between temperature and mortality by estimating the temperature-related mortality in Beijing, Shanghai, and Guangzhou. Methods Data of daily mortality, weather and air pollution in the three cities were collected. A distributed lag nonlinear model was established and used in analyzing the effects of temperature on mortality. Current and future net temperature-related mortality was estimated. Results The association between temperature and mortality was J-shaped, with an increased death risk of both hot and cold temperature in these cities. The effects of cold temperature on health lasted longer than those of hot temperature. The projected temperature-related mortality increased with the decreased cold-related mortality. The mortality was higher in Guangzhou than in Beijing and Shanghai. Conclusion The impact of temperature on health varies in the 3 cities of China, which may have implications for climate policy making in China.

中国城市中大气分粒级的粒子数浓度与每日死亡率

[背景]大气颗粒物-9健康结局之间的相关性已在全球范围内广为报道。然而，有关不同粒径颗粒物对健康影响的研究却十分有限。[目的]以中国沈阳为例，探索不同粒径颗粒物的数量浓度（particle number concentrations，PNCs）与每日死亡率之间的关系。[方法]研究时间为2006年12月1日至2008年11月30日，分别收集每日死因别死亡率和直径为0．25~10岬颗粒物的每日PNCs。用基于半泊松回归的广义相加模型来评估PNCs-9死亡率之间的相关性，同时采用自然样条平滑函数校正随时间变化的协变量、长期趋势及季节性趋势。[结果]在研究时间内，归因于非意外的自然死亡、心血管疾病和呼吸系统疾病的平均每日死亡数分别为67、32和7。直径为0．25-0．50gm的颗粒物PNCs与总死亡率和心血管疾病死亡率明显相关，但与呼吸系统疾病死亡率无明显相关性。与冷季相比，暖季里PNCs效应估计值较大，并且效应值随着颗粒物粒径的减小而增加。0．25～0．28p,m、O．35～0．40μm和0．45—0．50gm的颗粒物PNCs每增加1个IQR浓度，与之相关的总死亡风险分别增大2．41％（95％CI：1．23％～3．58％）、1．31％（95％CI：0．52％～2．09％）和0．45％（95％CI：0．04％-0．87％）。校正大气颗粒物和气态污染物的质量浓度后，这种相关性仍然保持稳定。[结论]研究结果提示，直径〈0．5μm的颗粒物可能是空气污染颗粒中导致不良健康影响的最主要成分，并且对健康的不利影响随着颗粒直径的减小而增加。

Hygroscopicity of ambient submicron particles in urban Hangzhou,China

In this study,hygroscopicity of size-segregated ambient submicron particles in urban Hangzhou was studied from 28th December 2009 to 18th January 2010,using a hygroscopicity-tandem differential mobility analyzer(H-TDMA).The submicron particles in Hangzhou showed a minor hygroscopic growth at 73%relative humidity(RH),and then grew significantly between 77%and 82%RH.Monomodal distribution accounted for 90%for 30 nm particles,17%for 50 nm particles,and less than 7%for particles larger than 50 nm at 82%RH.Deconvolution of the bimodal distribution indicated a less hygroscopic group and a more hygroscopic group,with the fraction of the more hygroscopic group increasing with the initial dry particle size and then remaining almost constant for accumulation mode particles.Our results imply that submicron particles in urban Hangzhou were almost entirely externally mixed,and the hygroscopic properties of ambient particles in urban Hangzhou were mainly a function of their size and chemical composition.