Objectives: To estimate long-term exposure to traffic-related air pollutants on an individual basis and to assess adverse health effects using a combination of air pollution measurement data, data ...from geographical information systems (GIS) and questionnaire data. Methods: 40 measurement sites in the city of Munich, Germany were selected at which to collect particulate matter with a 50% cut-off aerodynamic diameter of 2.5 µm (PM2.5) and to measure PM2.5 absorbance and nitrogen dioxide (NO2). A pool of GIS variables (information about street length, household and population density and land use) was collected for the Munich metropolitan area and was used in multiple linear regression models to predict traffic-related air pollutants. These models were also applied to the birth addresses of two birth cohorts (German Infant Nutritional Intervention Study (GINI) and Influence of Life-style factors on the development of the Immune System and Allergies in East and West Germany (LISA)) in the Munich metropolitan area. Associations between air pollution concentrations at birth address and 1-year and 2-year incidences of respiratory symptoms were analysed. Results: The following means for the estimated exposures to PM2.5, PM2.5 absorbance and NO2 were obtained: 12.8 μg/m3, 1.7×10−5 m−1 and 35.3 μg/m3, respectively. Adjusted odds ratios (ORs) for wheezing, cough without infection, dry cough at night, bronchial asthma, bronchitis and respiratory infections indicated positive associations with traffic-related air pollutants. After controlling for individual confounders, significant associations were found between the pollutant PM2.5 and sneezing, runny/stuffed nose during the first year of life (OR 1.16, 95% confidence interval 1.01 to 1.34) Similar effects were observed for the second year of life. These findings are similar to those from our previous analysis that were restricted to a subcohort in Munich city. The extended study also showed significant effects for sneezing, running/stuffed nose. Additionally, significant associations were found between NO2 and dry cough at night (or bronchitis) during the first year of life. The variable “living close to major roads” (<50 m), which was not analysed for the previous inner city cohort with birth addresses in the city of Munich, turned out to increase the risk of wheezing and asthmatic/spastic/obstructive bronchitis. Conclusions: Effects on asthma and hay fever are subject to confirmation at older ages, when these outcomes can be more validly assessed.
The effect of dog ownership during childhood on the development of allergy has been investigated in few studies with conflicting results. The association between dog contact and indoor endotoxin ...exposure during infancy and the development of allergic sensitisation and atopic disease up to age 6 yrs was investigated. Two ongoing birth cohorts, the German Infant Nutrition Intervention Programme (GINI; n = 1,962) and the Influences of Lifestyle Related Factors on the Human Immune System and Development of Allergies in Children (LISA; n = 1,193), were analysed. In both studies, information on children's contact with dogs and their allergic symptoms and doctor-diagnosed allergic disease were collected during follow-up using questionnaires. Specific immunoglobulin E to common aeroallergens was measured at age 6 yrs. House dust samples were collected at age 3 months and the amount of endotoxin was determined. Dog ownership in early childhood was associated with a significantly lower rate of mixed pollen and inhalant sensitisation but not with dog sensitisation or allergic symptoms and diseases up to age 6 yrs. Regular contact with dogs, without ownership, during childhood was not associated with those health outcomes. No associations were found between house dust endotoxin exposure during infancy and sensitisation outcomes. In conclusion, dog ownership in early childhood protects against the development of inhalant sensitisation and this effect cannot be attributed to the simultaneous exposure to endotoxin.
In vitro studies, animal experiments, and human exposure studies have shown how ambient air pollution increases the risk of atopic diseases. However, results derived from observational studies are ...inconsistent.
To assess the relationship between individual-based exposure to traffic-related air pollutants and allergic disease outcomes in a prospective birth cohort study during the first 6 years of life.
We studied 2,860 children at the age of 4 years and 3,061 at the age of 6 years to investigate atopic diseases and allergic sensitization. Long-term exposure to particulate matter (PM(2.5)), PM(2.5) absorbance, and long-term exposure to nitrogen dioxide (NO(2)) was assessed at residential addresses using geographic information systems based regression models and air pollution measurements. The distance to the nearest main road was used as a surrogate for traffic-related air pollutants.
Strong positive associations were found between the distance to the nearest main road and asthmatic bronchitis, hay fever, eczema, and sensitization. A distance-dependent relationship could be identified, with the highest odds ratios (ORs) for children living less than 50 m from busy streets. For PM(2.5) absorbance, statistically significant effects were found for asthmatic bronchitis (OR, 1.56; 95% confidence interval CI, 1.03-2.37), hay fever (OR, 1.59; 95% CI, 1.11-2.27), and allergic sensitization to pollen (OR, 1.40; 95% CI, 1.20-1.64). NO(2) exposure was associated with eczema, whereas no association was found for allergic sensitization.
This study provides strong evidence for increased risk of atopic diseases and allergic sensitization when children are exposed to ambient particulate matter.
Background: Some studies have suggested that particulate matter (PM) levels during pregnancy may be associated with birth weight. Road traffic is a major source of fine PM (PM with aerodynamic ...diameter $< 2.5 \mum$; PM2.5). Objective: We determined to characterize the influence of maternal exposure to atmospheric pollutants due to road traffic and urban activities on offspring term birth weight. Methods: Women from a birth cohort the LISA (Influences of Lifestyle Related Factors on the Human Immune System and Development of Allergies in Children) cohort who delivered a non-premature baby with a birth weight > 2,500 g in Munich metropolitan area were included. We assessed PM2.5, PM2.5absorbance (which depends on the blackness of PM2.5, a marker of traffic-related air pollution), and nitrogen dioxide levels using a land-use regression model, taking into account the type and length of roads, population density, land coverage around the home address, and temporal variations in pollution during pregnancy. Using Poisson regression, we estimated prevalence ratios (PR) of birth weight < 3,000 g, adjusted for gestational duration, sex, maternal smoking, height, weight, and education. Results: Exposure was defined for 1,016 births. Taking the lowest quartile of exposure during pregnancy as a reference, the PR of birth weight < 3,000 g associated with the highest quartile was 1.7 for PM2.595% confidence interval (CI), 1.2-2.7, 1.8 for PM2.5absorbance (95% CI, 1.1-2.7), and 1.2 for NO2(95% CI, 0.7-1.7). The PR associated with an increase of$1 \mug/m^3$in PM2.5levels was 1.13 (95% CI, 1.00-1.29). Conclusion: Increases in PM2.5levels and PM2.5absorbance were associated with decreases in term birth weight. Traffic-related air pollutants may have adverse effects on birth weight.
A novel technique to compress and expand a digitized signal is presented. The proposed methodology allows the storage memory to be cut in half and the sample frequency of the acquisition system to be ...doubled. It is useful in those cases in which the number of bits of the analog-to-digital converter is greater than the databus length of the microprocessor and the signal slew-rate is known. The proposed method also permits the clipping of unwanted spikes present in the signal. An application using a 12-bit analog-to-digital converter and an 8-bit microprocessor is given.< >
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