ABSTRACT
BACKGROUND:Airborne pollen is the most important factor to induce the seasonal allergic diseases.The production and dispersal of pollen are closely correlated with the meteorological factors.OBJECTIVE:To observe the correlation between the seven meteorological factors (air pressure,air temperature,humidity,precipitation,wind speed,evaporation capacity and sunshine) and the airborne pollen in Nanchang so as to provide theoretic evidences for preventing and treating anaphylactic disease in that region.DESIGN:Observational experiment. SETTING:Department of Allergic Reaction,Jiangxi Medical College.MATERIALS:An investigation on airbome pollen was performed for a year by Durham gravity method.Data of airborne pollen and the seven meteorological factors in urban area of Nanchang city were collected.METHODS:The top of the 4th experimental building in the southern yard of Jiangxi Medical College located in the center of Nanchang city was taken as exposed point.The pollen was surveyed by Durham gravity method from April 1st,2000 to March 31 st,2001.Meteorological data of the seven factors were collected every day and supplied by the Weather Bureau of Jiangxi Province.The correlation between meteorological factors and airborne pollen was analyzed by the multivariate Jinear stepwise regression analysis with SAS 6.12.MAIN OUTCOME MEASURES:The type,amount,seasonal distribution of airborne pollen and the correlation between the seven meteorological factors and the airborne pollen in urban area of Nanchang city. RESULTS:There were airborne pollens in Nanchang city all the year round,which included about 47 types.The main pollen season of Cupressaceae was in March,Pinaceae in March and April, and Cunninghamia R.Br in March,Chenopodium-Amaranthus and Ambrosia from August to November, Artemisia from September to November and Humulus in September.Gramineae had been scattering all seasons but mostly from June to October.In the correlation analysis between dispersal of airbome pollen and seven meteorological factors, multivariate linear stepwise regression analysis was conducted in some major polien counting in steady dispersal period and seven meteorological factors. The positive correlation was found in Pinaceae with air pressure,air temperature,wind speed and sunlight,and the negative correlation was found with precipitation and evaporation capacity.The positive correlation was found in Cupressaceae with air pressure,air temperature and sunlight,and negative correlation was found with humidity,precipitation,wind speed and evaporation capacity.The positive correlation was found in Ambrosia with air pressure,air temperature and wind speed,while negative correlation was found with humidity,precipitation,evaporation capacity and sunshine.The positive correlation was found in Artemisia with air pressure,air temperature and wind speed,while negative correlation was found with humidity,precipitation, evaporation capacity and sunshine.The positive correlation was found in Gramineae with air pressure and air temperature,while negative correlation was found with humidity,precipitation and evaporation capacity.However,if using count of total pollen in a year or half a year to analyze the relationship,the correlated factors were much fewer than that mentioned above.CONCLUSION:The dispersal of airborne pollen is related with the seven meteorological factors.It is better to use the grain amount of single pollen in its main pollen season to analyze the relationship with meteorological factors.
ABSTRACT
Objective To explore the relationship between vegetation and the distribution of Oncomelania snails inside and outside the embankments of Poyang Lake region. Methods The plantation and Oncomelania snails were surveyed at 4 villages and their related marshlands in Yugan, Nanchang and Jinxian counties by the stratified systematic sampling method. The investigation was targeted to the vegetation species,height,coverage and frequency of plantation and synchronously to the distribution of snails and infection of snails in marshland of high, middle and low altitudes,adjacent beaches as well in cultivated and waste land inside embankment. The relationship between vegetation dominant association and the distribution of snails in those area was analyzed. Results The vegetation inside and outside the embankment were remarkably diverse. Inside the embankment, the species of vegetation varied greatly and distributed randomly,and no snail was found. While outside the embankment,the distribution of vegetation characterized an unregulated annulus or patch. Plant's association types were distinct on marshlands. The snails mainly distributed in areas at 15-17 m altitude,closely related to the species of vegetation. The coverage of dominant plants,Carex cinerascen and Miscanthus sacchariflorus showed a quadratic curve correlation with the density of snails. Conclusions In the Poyang Lake region,plants and snails are impacted by common environmental factors,which then lead to their close association in distribution. It might be attributed to integrated impacts of changes in ecological factors that Oncomelania snails disappear gradually in areas inside embankment after construction of embankment.