***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background : Particulate matter < 10 μm ( PM10 ) from fossil fuel combustion is associated with an increased prevalence of respiratory symptoms in children and adolescents . However , the effect of PM10 on respiratory symptoms in young children is unclear . Methods : The association between primary PM10 ( particles directly emitted from local sources ) and the prevalence and incidence of respiratory symptoms was studied in a r and om sample cohort of 4400 Leicestershire children aged 1–5 years surveyed in 1998 and again in 2001 .  Annual exposure to primary PM10 was calculated for the home address using the Airviro dispersion model and adjusted odds ratios ( ORS ) and 95 % confidence intervals were calculated for each μg/m3 increase . Results : Exposure to primary PM10 was associated with the prevalence of cough without a cold in both 1998 and 2001 , with adjusted ORs of 1.21 ( 1.07 to 1.38 ) and 1.56 ( 1.32 to 1.84 ) respectively . For night time cough the ORs were 1.06 ( 0.94 to 1.19 ) and 1.25 ( 1.06 to 1.47 ) , and for current wheeze 0.99 ( 0.88 to 1.12 ) and 1.28 ( 1.04 to 1.58 ) , respectively . There was also an association between primary PM10 and new onset symptoms . The ORs for incident symptoms were 1.62 ( 1.31 to 2.00 ) for cough without a cold and 1.42 ( 1.02 to 1.97 ) for wheeze . Conclusion : In young children there was a consistent association between locally generated primary PM10 and the prevalence and incidence of cough without a cold and the incidence of wheeze which was independent of potential confounders Background : Evidence for a causal relationship between traffic-related air pollution and asthma has not been consistent across studies , and comparisons among studies have been difficult because of the use of different indicators of exposure . Methods : We examined the association between  traffic-related pollution and childhood asthma in 208 children from 10 southern California communities using multiple indicators of exposure . Study subjects were r and omly selected from participants in the Children 's Health Study .  Outdoor nitrogen dioxide ( NO2 )  was measured in summer and winter outside the home of each child . We also determined residential distance to the nearest freeway , traffic volumes on roadways within 150 meters , and model-based estimates of pollution from nearby roadways . Results : Lifetime history of doctor-diagnosed asthma was associated with outdoor NO2 ;  the odds ratio ( OR ) was 1.83 ( 95 % confidence interval = 1.04–3.22 ) per increase of 1 interquartile range ( IQR = 5.7 ppb ) in exposure . We also observed increased asthma associated with closer residential distance to a freeway ( 1.89 per IQR ; 1.19–3.02 ) and with model-based estimates of outdoor pollution from a freeway ( 2.22 per IQR ; 1.36–3.63 ) . These 2 indicators of freeway exposure and measured NO2 concentrations were also associated with wheezing and use of asthma medication . Asthma was not associated with traffic volumes on roadways within 150 meters of homes or with model-based estimates of pollution from nonfreeway roads . Conclusions : These results indicate that respiratory health in children is adversely affected by local exposures to outdoor NO2 or other freeway-related pollutants The impact of inner city air pollution on the development of respiratory and atopic diseases in childhood is still unclear . In a cross sectional study in Dresden , Germany , 5,421 children in two age groups ( 5 - 7 yrs and 9 - 11 yrs ) were studied according to the International Study of Asthma and Allergies in Childhood ( ISAAC ) phase II protocol . The prevalences of wheezing and cough as well as doctor diagnosed asthma and bronchitis were assessed by parental question naires . Children also underwent skin-prick testing , venipuncture for the measurement of serum immunoglobulin (Ig)E  ,  lung function testing and a bronchial challenge test ( 4.5 % saline ) to assess airway hyperresponsiveness . Exposure was assessed on an individual basis by relating mean annual air pollution levels ( SO2 , NO2 , CO , benzene , and O3 ) which had been measured on a 1 km2 grid , to the home and school address of each study subject . After adjusting for potential confounding factors an increase in the exposure to benzene of 1 microg x m3 air was associated with an increased prevalence of morning cough ( adjusted odds ratio ( aOR ) ) : 1.15 ; 1.04 - 1.27 ) and bronchitis ( aOR : 1.11 ; 1.03 - 1.19 ) . Similar associations were observed for NO2 and CO . In turn , the prevalences of atopic sensitization , symptoms of atopic diseases and bronchial hyperresponsiveness were not positively associated with exposure to any of these pollutants . It is concluded that in this study a moderate increase in exposure to traffic-related air pollution was associated with an increased prevalence of cough and bronchitis , but not with atopic conditions in children Living conditions in eastern Germany have changed rapidly since unification in 1990 and little is known about how these changes affect the prevalence of atopic diseases . This study describes methods and prevalences of a large epidemiological project investigating determinants of childhood asthma and allergies in eastern ( Dresden and Leipzig ) and western ( Munich ) Germany in 1995/1996 . Community based r and om sample s of 9 - 11 yr old children in Dresden ( n=3,017 ) and Munich ( n=2,612 ) , and of 5 - 7 yr old children in Dresden ( n=3,300 ) , Leipzig ( n=3,167 ) and Munich ( n=2,165 ) were studied by parental question naires , bronchial challenges with hypertonic saline , skin examination , skin-prick tests , and measurements of specific and total serum immunoglobulin (Ig)E using Phase II modules of the International Study of Asthma and Allergies in Childhood ( ISAAC ) . In 9 - 11 yr old children , the prevalence of physician diagnosed asthma ( 7.9 % versus 10.3 % ; p<0.01 ) and bronchial hyperresponsiveness ( 15.7 % versus 19.9 % ; p<0.05 ) was lower in Dresden than in Munich . No difference between Munich and Dresden was observed in the prevalence of diagnosed hay fever , skin test reactivity to > or = 1 allergen , and increased levels ( > 0.35 kU x L(-1 ) ) of specific IgE against inhalant and food allergens . Symptoms and visible signs of atopic eczema tended to be more prevalent in Dresden . Similar East-West differences between the three study areas were seen in the younger age group . These findings are in line with recently observed increases in the prevalence of hay fever and atopic sensitization , but not of asthma and bronchial hyperresponsiveness , among 9 - 11 yr old children in Leipzig BACKGROUND Fine particulate matter has been linked to allergies by experimental and epidemiological data having used aggregated data or concentrations provided by fixed-site monitoring stations , which may have led to misclassification of individual exposure to air pollution . METHODS A semi-individual design was employed to relate individual data on asthma and allergy of 5338 school children ( 10.4 + /- 0.7 years ) attending 108 r and omly chosen schools in 6 French cities to the concentrations of PM2.5 ( fine particles with aerodynamic diameter 2.5 microm ) assessed in proximity of their homes . Children underwent a medical visit including  skin prick test ( SPT ) to common allergens , exercise-induced bronchial ( EIB ) reactivity and skin examination for flexural dermatitis . Their parents filled in a st and ardised health question naire . RESULTS After adjustment for confounders and NO2 as a potential modifier , the odds of suffering from EIB and flexural dermatitis at the period of the survey , past year atopic asthma and SPT positivity to indoor allergens were significantly increased in residential setting s with PM2.5 concentrations exceeding 10 microg/m3 ( WHO air quality limit values ) . The relationships were strengthened in long-term residents ( current address for at least 8 years ) . CONCLUSIONS Findings support the hypothesis that changes in allergy prevalence observed in recent decades might be partly related to interactions between traffic-related air pollution and allergens . Further longitudinal investigations are needed to corroborate such results BACKGROUND Data for trends in prevalence of asthma , allergic rhinoconjunctivitis , and eczema over time are scarce . We repeated the International Study of Asthma and Allergies in Childhood ( ISAAC ) at least 5 years after Phase One , to examine changes in the prevalence of symptoms of these disorders . METHODS For the ISAAC Phase Three study , between 2002 and 2003 , we did a  cross-sectional question naire survey of 193,404 children aged 6 - 7 years from 66 centres in 37 countries , and 304,679 children aged 13 - 14 years from 106 centres in 56 countries , chosen from a r and om sample of schools in a defined geographical area . FINDINGS Phase Three was completed a mean of 7 years after Phase One . Most centres showed a change in prevalence of 1 or more SE for at least one disorder , with increases being twice as common as decreases , and increases being more common in the 6 - 7 year age-group than in the 13 - 14 year age-group , and at most levels of mean prevalence . An exception was asthma symptoms in the older age-group , in which decreases were more common at high prevalence . For both age-groups , more centres showed increases in all three disorders more often than showing decreases , but most centres had mixed changes . INTERPRETATION The rise in prevalence of symptoms in many centres is concerning , but the absence of increases in prevalence of asthma symptoms for centres with existing high prevalence in the older age-group is reassuring . The divergent trends in prevalence of symptoms of allergic diseases form the basis for further research into the causes of such disorders Conflicting results have been reported for the relationship between traffic exposure and inception of atopy . The effect of traffic on the prevalence of asthma and atopy at school age was investigated in a representative population . R and om sample s of schoolchildren ( n=7,509 , response rate 83.7 % ) were studied using the International Study of Asthma and Allergies in Childhood phaseII protocol with skinprick tests , measurements of specific immunoglobulin E and lung function . Traffic exposure was assessed via traffic counts and by an emission model which predicted soot , benzene and nitrogen dioxide ( NO2 ) .  Traffic counts were associated with current asthma , wheeze and cough . In children with tobaccosmoke exposure , traffic volume was additionally associated with a positive skinprick test . Cough was associated with soot , benzene and NO2 , current asthma with soot and benzene , and current wheeze with benzene and NO2 . No pollutant was associated with allergic sensitisation . High vehicle traffic was associated with asthma , cough and wheeze , and in children additionally exposed to environmental tobacco smoke , with allergic sensitisation . However , effects of socioeconomic factors associated with living close to busy roads can not be ruled out The effect of road vehicle traffic pollution on asthma is still not clearly understood . However , any effect is likely to be most marked among those who live within 150 m of a main road , because this is the distance within which concentrations of primary vehicle traffic pollutants are raised above ambient background levels . We have investigated the relation between proximity of the family home to the nearest main road , estimated objective ly using geographical information system software , and the risk of wheeze in the past year in a case-control sample of 6,147 primary schoolchildren ( age 4 to 11 yr ) and a r and om cross-sectional sample of 3,709 secondary schoolchildren ( age 11 to 16 yr ) in Nottingham , United Kingdom . Among children living within 150 m of a main road , the risk of wheeze increased with increasing proximity by an odds ratio ( OR ) of 1.08 ( 95 % confidence interval [ CI ] 1.00 to 1.16 ) per 30-m increment in primary schoolchildren , and 1.16 ( 1.02 to 1.32 ) in secondary schoolchildren . Most of the increased risk was localized to within 90 m of the roadside . Among primary schoolchildren , effects were stronger in girls than boys ( p(interaction ) = 0.02 ) . Living within approximately 90 m of a main road is associated with a proximity-related increase in the risk of wheezing illness in children Background : Urban air pollution can trigger asthma symptoms in children , but there is conflicting evidence on effects of long-term exposure on lung function , onset of airway disease and allergic sensitization . Methods : The spatial distribution of nitrogen oxides from traffic ( traffic-NOx ) and inhalable particulate matter from traffic ( traffic-PM10 ) in the study area was assessed with emission data bases and dispersion modeling . Estimated levels were used to assign first-year exposure levels for children in a prospect i ve birth cohort ( n = 4089 ) , by linking to 
    Output:
    
Overall , the review by Rodriguez-Villamizar ( 1 ) reminds us that while air quality improves in much of the world , and while Canada enjoys excellent air quality in general , advanced research methods are now able to detect subtle signals of adverse health effects better than ever before , such that we see potential benefit in further air quality gains .