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Paper text:
pollens are important allergens which trigger symptoms in patients with allergic diseases such as allergic rhinitis ( ar ) and asthma .
pollens during pollination period generally trigger asthma . at the time of seasonal peaks , large number of pollen grains
are liberated from the trees and remain suspended in the air . in various studies , it was observed that number of patients attending hospital increases with higher pollen count in that period .
therefore , knowledge about pollen season of the area may prove an important tool for a doctor treating asthmatic patients .
pollen count varies at different places and is affected by the topographical factors , local vegetation of the area , and meteorological factors .
pollen calendar is a useful tool in the diagnosis and management of allergic disorders . during pollination season ,
sensitive subjects develop symptoms of the disease , therefore , chances of getting new patients increases
. however , we could not find significant indian data relating pollen counts with clinical symptoms except a jaipur study carried out in 19571958 .
therefore , we conducted this study to characterize main types of pollens in jaipur and to find a correlation with the hospital visit of new patients of asthma and ar .
the study was carried out at asthma bhawan , located in the western part of jaipur .
new patients of ar and asthma who were residents of jaipur were included in the study .
skin prick tests ( spts ) were performed using allergen extracts , saline as negative control and histamine as positive control .
it was considered positive when wheal diameter was more than 3 mm of size , or it was with pseudopodia formation .
pollen sampling was carried out from january 1 , 2011 , to december 31 , 2012 .
the aerobiological samples of pollens were collected through burkard 24 h spore trap system , which is a type of suction sampler .
although sampling collected at multiple places is desirable yet pollen sampling carried at one place is also shown be representative of 30 km radius area .
the method of pollen collection , preparation of slide and analysis of sample had been described .
the counts represent number of pollens per cubic meter of air in 24 h. traditionally different species of poaceae and cheno - amaranthaceae family are not described separately .
however , we were able to differentiate some of the species from the poaceae family .
these include cynodon , hordeum vulgare , pennisetum glaucum , saccharum munja , sorghum vulgare , triticum aestivum , and zea mays .
similarly , the identifiable pollens of cheno - amaranthaceae family were amaranthus spinosus , spinacia oleracea , and chenopodium album .
most of the pollens of chenopodiaceae and amaranthaceae family which could not be differentiated were grouped under the heading of cheno - amaranthaceae .
the total number of new patients attending the hospital during 12 months was averaged for 2 years .
pollen counts of various species were also used in making the pollen calendar of the jaipur .
an average monthly pollen count of trees , weeds , and grasses were correlated with an average number of new patients during that month .
correlation of the spt with the pollen counts of both years was also done using pearson correlation coefficient .
an average monthly pollen count of trees , weeds , and grasses were correlated with an average number of new patients during that month .
correlation of the spt with the pollen counts of both years was also done using pearson correlation coefficient .
during 2011 and 2012 , the average number of new patients of asthma and ar per year attending asthma bhawan outpatient department was 1692.5 . during these years
the numbers of pollen trapped were 13,738 and 15,183 respectively with yearly average of 14,460.5 pollens [ table 1 ] .
analysis of pollen data of 2 years showed 37 types of pollen species or families .
since many of these pollens were identified only after this study therefore during this period , spt tests were carried out for only 17 pollens as identified in the earlier study .
average pollen counts and number of new outpatient department patients during 12 months and their correlation two seasonal peaks of pollen count were observed .
the first peak was mainly due to trees pollens while the second peak was due to weeds and grasses pollens .
major part of the first peak was in march , and it had holoptelea ( 65% ) as the major contributor . while major part of the second peak was contributed by grasses family . in the second season , september had the highest number , and the grasses ( 38% ) contributed the most .
the main contributors of the total pollen counts for 2 years were poaceace family ( 42% ) and cheno - amaranthaceae family ( 30% ) . during january and
cheno - amaranthaceae , poaceace , and holoptelea integrifolia are the highest pollen generating plant family / species [ table 2 ] .
top ten pollen generating plant families / species during 2 years in this study , 37 types of pollen species / families were identified in the 2 years duration .
out of these 25 species / families were having a limited period of pollination in the year and 12 species / families had their pollens in the aerobiology of jaipur throughout the year .
pollen calendar was prepared based on the presence of different pollens in specific part of the year [ figure 1 ] .
pollen calendar of the pollens in jaipur when average monthly pollen counts were correlated with the number of new patients during that period , a positive correlation was found with grass pollens .
the correlation of the individual pollen with the spt of patients gave the correlation in only one of the species that is c. album , a weed .
pollen count peaks were observed during march to april and august to october in both years .
many studies have demonstrated that peak pollen counts were associated with higher number of hospital visits by new asthmatic or ar patients . in our study also
a significant positive correlation was demonstrated between number of monthly new asthmatic and ar patients and grass pollen count . however , correlation was not significant with weeds and trees .
although in the study done in kuwait , the number of new patients of ar were significantly correlated with weeds but not to grass and trees . in yet another study , episodes of asthma exacerbations in children were significantly correlated with pollen counts .
the cause and effect relationship was further established in a study wherein a cohort of asthmatic patients exacerbations were monitored at monthly interval , and these were significantly correlated with the pollen counts in the environment .
similarly , an earlier study done in jaipur in 19571958 showed that the number of respiratory allergy patients in allergy clinic were proportional to the fluctuation in the pollen count .
all these evidence suggest strong association between the presence of respiratory symptoms and presence of pollens in the environment .
it emphasizes the need of proper knowledge of pulmonologists about the environmental pollens and vegetations of the area .
a proper pollen calendar may prove a useful tool for clinicians involved in the treatment of patients with respiratory allergy .
we could not compare data of absolute number of pollen counts of our study with that of earlier study because of variation in the methodology .
however , the proportion of various types of vegetation can be compared which showed interesting differences .
have published that in jaipur tree pollens were 50% while grass pollens were only 14% . in the present study , tree pollens constituted only 17% while proportion of grass is much higher ( 42% ) [ figure 2 ] . probably urbanization has replaced trees by concrete jungles thereby causing reduced pollen counts . in our study ,
grass pollens were present throughout the year and peak was present during postmonsoon period . in earlier jaipur
study grass pollens were limited only during postmonsoon period . probably with urbanization in jaipur during last seven decades density of trees
proportion of pollens of trees , weeds and grasses during 19571958 and 20112012 in jaipur a similar study was conducted in delhi from september 1990 to august 1997 . during the 7-year period ,
this was attributed to the large clearance of vegetation from the city . in their study
studies done in different parts of india showed that there is wide variation in number of pollens and most frequent pollen . in gwalior , pollen grains mainly belonged to families of poaceae and amaranth - chenopodiacae similar to our study , while in lucknow , grasses and holoptelea were main pollens . in the majority of places ,
two peaks of pollen seasons were observed but in north kashmir peak pollen counts were observed during march  september period .
number of new patients of asthma and ar attending hospital were significantly correlated with grass pollen counts .
knowledge of pollen calendar may prove useful in the evaluation of patients with seasonal exacerbation of symptoms of respiratory allergy .
aims and objectives : environmental pollens are known to cause exacerbation of symptoms of patients with allergic rhinitis ( ar ) and asthma . during pollen months , 
 number of patients visiting hospital has been shown to increase in some studies . however , in india , such studies are lacking . 
 therefore , we aimed to study pollen counts and to find its correlation with number of new patients attending asthma bhawan for 2 years.materials and methods : aerobiological sampling was done using burkard 24 h spore trap system . 
 the site selected for the entrapment of the air spore was the building of asthma bhawan situated at vidhyadhar nagar , jaipur . 
 new patients coming with problems of respiratory allergy such as ar or asthma were recruited in the study . 
 skin prick tests ( spts ) were carried out after obtaining consent in these patients . 
 monthly pollen counts of trees , weeds and grasses were correlated with the number of new patients . 
 pollen calendar was prepared for 2 years.results:average annual pollen count during 2011 and 2012 were 14,460.5 . in the analysis , 
 37 types of species or families were identified . 
 pollen count showed two seasonal peaks during march  april and from august to october . 
 january and june showed the lowest pollen counts in 2 years . 
 average monthly count of grass pollens showed significant correlation with number of new patients ( r = 0.59 ) . 
 however , monthly pollen count of trees and weeds did not correlate . 
 the correlation of the pollen count of individual pollen with the spt positivity to that pollen showed significant correlation with chenopodium album only.conclusions:it can be concluded that there were two peaks of pollen count in a year during march  april and august  october . 
 average monthly pollen counts of grass were significantly correlated with the number of hospital visits of new patients .