A longitudinal study of indoor nitrogen dioxide levels and respiratory symptoms in inner-city children with asthma

Background

The effect of indoor nitrogen dioxide concentrations on asthma morbidity among inner-city preschool children is uncertain.

Objectives

Our goal was to estimate the effect of indoor NO₂ concentrations on asthma morbidity in an inner-city population while adjusting for other indoor pollutants.

Methods

We recruited 150 children (2–6 years of age) with physician-diagnosed asthma from inner-city Baltimore, Maryland. Indoor air was monitored over a 72-hr period in the children’s bedrooms at baseline and 3 and 6 months. At each visit, the child’s caregiver completed a questionnaire assessing asthma symptoms over the previous 2 weeks and recent health care utilization.

Results

Children were 58% male, 91% African American, and 42% from households with annual income < $25,000; 63% had persistent asthma symptoms. The mean (± SD) in-home NO₂ concentration was 30.0 ± 33.7 (range, 2.9–394.0) ppb. The presence of a gas stove and the use of a space heater or oven/stove for heat were independently associated with higher NO₂ concentrations. Each 20-ppb increase in NO₂ exposure was associated significantly with an increase in the number of days with limited speech [incidence rate ratio (IRR) = 1.15; 95% confidence interval (CI), 1.05–1.25], cough (IRR = 1.10; 95% CI, 1.02–1.18), and nocturnal symptoms (IRR = 1.09; 95% CI, 1.02–1.16), after adjustment for potential confounders. NO₂ concentrations were not associated with increased health care utilization.

Conclusions

Higher indoor NO₂ concentrations were associated with increased asthma symptoms in preschool inner-city children. Interventions aimed at lowering NO₂ concentrations in inner-city homes may reduce asthma morbidity in this vulnerable population.     

Temporal and Spatial Patterns of Ambient Endotoxin Concentrations in Fresno,California

Background

Endotoxins are found in indoor dust generated by human activity and pets, in soil, and adsorbed onto the surfaces of ambient combustion particles. Endotoxin concentrations have been associated with respiratory symptoms and the risk of atopy and asthma in children.

Objective

We characterized the temporal and spatial variability of ambient endotoxin in Fresno/Clovis, California, located in California’s Central Valley, to identify correlates and potential predictors of ambient endotoxin concentrations in a cohort of children with asthma [Fresno Asthmatic Children’s Environment Study (FACES)].

Methods

Between May 2001 and October 2004, daily ambient endotoxin and air pollutants were collected at the central ambient monitoring site of the California Air Resources Board in Fresno and, for shorter time periods, at 10 schools and indoors and outdoors at 84 residences in the community. Analyses were restricted to May–October, the dry months during which endotoxin concentrations are highest.

Results

Daily endotoxin concentration patterns were determined mainly by meteorologic factors, particularly the degree of air stagnation. Overall concentrations were lowest in areas distant from agricultural activities. Highest concentrations were found in areas immediately downwind from agricultural/pasture land. Among three other measured air pollutants [fine particulate matter, elemental carbon (a marker of traffic in Fresno), and coarse particulate matter (PM_c)], PM_c was the only pollutant correlated with endotoxin. Endotoxin, however, was the most spatially variable.

Conclusions

Our data support the need to evaluate the spatial/temporal variability of endotoxin concentrations, rather than relying on a few measurements made at one location, in studies of exposure and and respiratory health effects, particularly in children with asthma and other chronic respiratory diseases.     

Air Pollution Exposure during Pregnancy and Childhood Autistic Traits in Four European Population-Based Cohort Studies: The ESCAPE Project

Background

Prenatal exposure to air pollutants has been suggested as a possible etiologic factor for the occurrence of autism spectrum disorder.

Objectives

We aimed to assess whether prenatal air pollution exposure is associated with childhood autistic traits in the general population.

Methods

Ours was a collaborative study of four European population-based birth/child cohorts—CATSS (Sweden), Generation R (the Netherlands), GASPII (Italy), and INMA (Spain). Nitrogen oxides (NO₂, NO_x) and particulate matter (PM) with diameters of ≤ 2.5 μm (PM_2.5), ≤ 10 μm (PM₁₀), and between 2.5 and 10 μm (PM_coarse), and PM_2.5 absorbance were estimated for birth addresses by land-use regression models based on monitoring campaigns performed between 2008 and 2011. Levels were extrapolated back in time to exact pregnancy periods. We quantitatively assessed autistic traits when the child was between 4 and 10 years of age. Children were classified with autistic traits within the borderline/clinical range and within the clinical range using validated cut-offs. Adjusted cohort-specific effect estimates were combined using random-effects meta-analysis.

Results

A total of 8,079 children were included. Prenatal air pollution exposure was not associated with autistic traits within the borderline/clinical range (odds ratio = 0.94; 95% CI: 0.81, 1.10 per each 10-μg/m³ increase in NO₂ pregnancy levels). Similar results were observed in the different cohorts, for the other pollutants, and in assessments of children with autistic traits within the clinical range or children with autistic traits as a quantitative score.

Conclusions

Prenatal exposure to NO₂ and PM was not associated with autistic traits in children from 4 to 10 years of age in four European population-based birth/child cohort studies.

Citation

Guxens M, Ghassabian A, Gong T, Garcia-Esteban R, Porta D, Giorgis-Allemand L, Almqvist C, Aranbarri A, Beelen R, Badaloni C, Cesaroni G, de Nazelle A, Estarlich M, Forastiere F, Forns J, Gehring U, Ibarluzea J, Jaddoe VW, Korek M, Lichtenstein P, Nieuwenhuijsen MJ, Rebagliato M, Slama R, Tiemeier H, Verhulst FC, Volk HE, Pershagen G, Brunekreef B, Sunyer J. 2016. Air pollution exposure during pregnancy and childhood autistic traits in four European population-based cohort studies: the ESCAPE Project. Environ Health Perspect 124:133–140; http://dx.doi.org/10.1289/ehp.1408483     

Health and Safety of Child Care Centers: An Analysis of Licensing Specialists’ Reports of Routine,Unannounced Inspections

Objectives. We assessed the prevalence of regulatory noncompliance of licensed child care centers and identified factors associated with improved compliance.Methods. We analyzed 676 routine, unannounced reports of child care centers collected by the Connecticut Department of Public Health licensing specialists over a 2-year time period, included characteristics of centers, and created categories of regulations.Results. The sample included 41% of licensed child care centers. Of the 13 categories of regulations in the analyses, 7 categories (outdoor safety, indoor safety, indoor health, child and staff documentation, emergency preparedness, infant-toddler indoor health, and infant-toddler indoor safety) had regulations with center noncompliance greater than 10%. Playground hazard-free was the regulation with the highest frequency (48.4%) of noncompliance. Compliance with the regulation for 20 hours of continuing education per year for child care providers was the characteristic most frequently associated with regulations compliance.Conclusions. Efforts to support continuing education of child care providers are essential to improve and sustain healthy and safe early-care and education programs. Analyses of state child care licensing inspection reports provide valuable data and findings for strategic planning efforts.Attendance in out-of-home child care is a necessity for many children and poses both risks and benefits. Approximately 60% of children younger than 6 years both in Connecticut and nationally have mothers in the workforce.1,2 In Connecticut, about 85 000 young children are cared for in approximately 1600 licensed child care centers and group homes.3 When the quality of child care or early care and education (ECE) is suboptimal, children are at greater risk for infectious diseases, injuries, and inadequate nurturing.4–6 However, high quality ECE offers several benefits, including developmentally appropriate care, fewer illnesses and injuries, greater likelihood of health care access, health screenings, early identification and referral for health, developmental and behavioral concerns, and care for children with special health care needs.6,7 Quality ECE is a critical component of a healthy trajectory necessary for children’s readiness to learn and is associated with long-term health and well-being.8–10Initiatives to improve health and safety for children in ECE are occurring on both national and state levels. To promote access to healthy, safe, and developmentally appropriate ECE programs, the US Department of Health and Human Services Maternal Child Health Bureau, in partnership with the American Public Health Association and the American Academy of Pediatrics, has supported national health and safety standards (Caring for Our Children ([CFOC]),11 state grants, and resource centers for information, technical assistance, and training.12 Furthermore, the National Association for the Education of Young Children (NAEYC), the professional organization of early childhood professionals, has aligned their accreditation standards with CFOC health and safety standards.13 Simultaneously, as states launch universal preschool initiatives to better prepare children for kindergarten14 many are recognizing that children’s health status during the preschool years influences their readiness to learn.8,15Although efforts are under way to promote quality ECE through implementation of national health and safety standards and accreditation, state child care regulations represent the minimum requirements below which a program should not operate.11 The intent of regulations is to ensure a basic level of acceptable care. Because state regulations vary widely, there are limited comparisons of child care health and safety across states. In a 1995 study researchers measured child care quality in center classrooms in 4 states, including Connecticut, using the Infant-Toddler and the Early Childhood Environment Rating Scales, instruments which were initially designed to assess quality in early care programs for research purposes.16 Connecticut ranked highest in health and safety items, which the researchers attributed to strong regulations. Nevertheless, even in Connecticut only 24% of the classrooms were rated as good quality, that is, developmentally appropriate, healthy, and safe. No summary data on the health and safety status of Connecticut child care centers have been reported since that study, and no comprehensive report of routine, unannounced inspections, which measure minimal health and safety rather than quality, has been released.All states require periodic, routine, unannounced inspections of ECE facilities to monitor compliance with state child care regulations.17 CFOC recommends that all ECE programs should be inspected at least semiannually.11 Connecticut child care regulations require every other year, unannounced, random inspections of child care centers caring for 13 or more children and group family care homes caring for 7 to 12 children.18 However, the findings are not analyzed or published.This study addressed the following research questions. (1) What is the frequency of regulatory noncompliance of child care centers as determined by unannounced, random inspections? (2) Is there an association of regulatory compliance with the following child care center factors: (a) NAEYC accreditation, (b) source of funding (state-funded child care, School Readiness [public pre-K)] programs, Head Start), (c) access to a trained child care health consultant (CCHC), (d) compliance with continuing education of child care providers, and (e) median household income of child care center location?As university-based researchers, we received funding from a private foundation to conduct this study. We used data collected by the Connecticut Department of Public Health (DPH) Child Care Licensing Specialists and other data sets to explore these questions and provide the first aggregate report of the health and safety status of Connecticut licensed child care centers.     

Personal endotoxin exposure in a panel study of school children with asthma

Background

Endotoxin exposure has been associated with asthma exacerbations and increased asthma prevalence. However, there is little data regarding personal exposure to endotoxin in children at risk, or the relation of personal endotoxin exposure to residential or ambient airborne endotoxin. The relation between personal endotoxin and personal air pollution exposures is also unknown.

Methods

We characterized personal endotoxin exposures in 45 school children with asthma ages 9-18 years using 376 repeated measurements from a PM_2.5 active personal exposure monitor. We also assayed endotoxin in PM_2.5 samples collected from ambient regional sites (N = 97 days) and from a subset of 12 indoor and outdoor subject home sites (N = 109 and 111 days, respectively) in Riverside and Whittier, California. Endotoxin was measured using the Limulus Amoebocyte Lysate kinetic chromogenic assay. At the same time, we measured personal, home and ambient exposure to PM_2.5 mass, elemental carbon (EC), and organic carbon (OC). To assess exposure relations we used both rank correlations and mixed linear regression models, adjusted for personal temperature and relative humidity.

Results

We found small positive correlations of personal endotoxin with personal PM_2.5 EC and OC, but not personal PM_2.5 mass or stationary site air pollutant measurements. Outdoor home, indoor home and ambient endotoxin were moderately to strongly correlated with each other. However, in mixed models, personal endotoxin was not associated with indoor home or outdoor home endotoxin, but was associated with ambient endotoxin. Dog and cat ownership were significantly associated with increased personal but not indoor endotoxin.

Conclusions

Daily fixed site measurements of endotoxin in the home environment may not predict daily personal exposure, although a larger sample size may be needed to assess this. This conclusion is relevant to short-term exposures involved in the acute exacerbation of asthma.     

Preterm birth and exposure to air pollutants during pregnancy

Background

Research has shown that prenatal exposure to air pollutants may have a detrimental effect on fetal development, with the strength of the relationship depending on the effect being studied. The evidence to date, however, is insufficient to establish a direct causal link between such exposure and preterm delivery. This study evaluates the specific effect of prenatal exposure to NO₂ and benzene on preterm births.

Methods

The population under study comprised 785 pregnant women who formed part of the INMA cohort in Valencia, Spain (2003–2005). Multiple regression models were used for mapping outdoor nitrogen dioxide (NO₂) and benzene levels throughout the area. Individual exposure was assigned as the estimated outdoor levels at each woman’s home measured during each trimester as well as throughout the entire pregnancy. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated in order to assess the association between preterm birth and exposure to NO₂ and benzene. The shape of the exposure–response curve between air pollution and the risk of preterm birth was analyzed with a flexible approach, introducing a natural cubic spline for air pollution levels into the model.

Results

Pregnant women exposed to NO₂ and benzene have an increased risk of preterm birth. This risk was shown to be significant when women were exposed to NO₂ levels >46.2 μg/m³ during the second and third trimesters as well as throughout the entire pregnancy and to benzene levels >2.7 μg/m³ throughout the entire pregnancy.

Conclusion

These results suggest that maternal exposure to traffic-related air pollution is associated with preterm birth.     

Effect of long-term exposure to air pollution on anxiety and depression in adults: A cross-sectional study

Background

The association between exposure to air pollutants and mental disorders among adults has been suggested, although results are not consistent.

Effects of the Caregiver Interaction Profile Training on Caregiver–Child Interactions in Dutch Child Care Centers: A Randomized Controlled Trial

Background

Previous studies underscore the need to improve caregiver–child interactions in early child care centers.

Objective

In this study we used a randomized controlled trial to examine whether a 5-week video feedback training can improve six key interactive skills of caregivers in early child care centers: Sensitive responsiveness, respect for autonomy, structuring and limit setting, verbal communication, developmental stimulation, and fostering positive peer interactions.

Method

A total of 139 caregivers from 68 early child care groups for 0- to 4-year-old children in Dutch child care centers participated in this RCT, 69 in the intervention condition and 70 in the control condition. Caregiver interactive skills during everyday interactions with the children were rated from videotape using the Caregiver Interaction Profile (CIP) scales at pretest, posttest, and follow-up 3 months after the posttest.

Results

Results at posttest indicate a significant positive training effect on all six caregiver interactive skills. Effect sizes of the CIP training range between d = 0.35 and d = 0.79. Three months after the posttest, caregivers in the intervention group still scored significantly higher on sensitive responsiveness, respect for autonomy, verbal communication, and fostering positive peer interactions than caregivers in the control group with effect sizes ranging between d = 0.47 and d = 0.70.

Conclusions

This study shows that the quality of caregiver–child interactions can be improved for all six important caregiver skills, with a relatively short training program. Possible ways to further improve the training and to implement it in practice and education are discussed.

     

NO2 and children's respiratory symptoms in the PATY study

Objectives

NO₂ is a major urban air pollutant. Previously reported associations between ambient NO₂ and children''s respiratory health have been inconsistent, and independent effects of correlated pollutants hard to assess. The authors examined effects of NO₂ on a spectrum of 11 respiratory symptoms, controlling for PM₁₀ and SO₂, using a large pooled dataset.

Methods

Cross sectional studies were conducted in Russia, Austria, Italy, Switzerland, and the Netherlands, during 1993–99, contributing in total 23 955 children. Study‐specific odds ratios for associations with ambient NO₂ are estimated using logistic regressions with area‐level random effects. Heterogeneity between study‐specific results, and mean estimates (allowing for heterogeneity) are calculated.

Results

Long term average NO₂ concentrations were unrelated to prevalences of bronchitis or asthma. Associations were found for sensitivity to inhaled allergens and allergy to pets, with mean odds ratios around 1.14 per 10 μg/m³ NO₂. SO₂ had little confounding effect, but an initial association between NO₂ and morning cough was reduced after controlling for PM_10. Associations with reported allergy were not reduced by adjustment for the other pollutants. Odds ratios for allergic symptoms tended to be higher for the 9–12 year old children compared with the 6–8 year old children.

Conclusions

Evidence for associations between NO₂ and respiratory symptoms was robust only for inhalation allergies. NO₂ most likely is acting as an indicator of traffic related air pollutants, though its direct effect cannot be ruled out. This remains important, as policies to reduce traffic related air pollution will not result in rapid reductions.Links between pollution and health are hardly doubted since the disastrous great London Smog and similar incidents, yet uncertainties remain about risks at lower concentrations.¹ There is also considerable debate about the pollutants responsible for observed health effects. In the recent decade much attention has been given to ambient particles, often characterised by the concentration of PM₁₀ or PM_2.5. NO₂ is one of the major gaseous air pollutants, which continues to raise concern, and it is one of the two pollutants regulated by the European Union (PM₁₀ being the other).¹ Though NO₂ is related to combustion processes in general, in outdoor urban environments, NO₂ is considered a marker for the complex of traffic related pollutants. NO₂ characterises the spatial variation of traffic related air pollution better than PM₁₀ or PM_2.5, and observed health effects of urban air pollution characterised by NO₂ have extended from impairment of lung function growth up to premature respiratory death.^2,3Most research on NO₂ and children''s health investigates acute effects. Several studies of asthmatic children found NO₂ related increases in attacks.^4,5,6,7 Some found associations with other symptoms, but no asthma exacerbation.^8,9 The large PEACE study found no consistent NO₂ effects on respiratory symptoms or lung function.¹⁰ Several studies found effects of other pollutants, but not NO₂.^11,12,13Within the literature from cross sectional studies, NO₂ is most clearly linked to cough, with consistent reports of positive (if sometimes weak) associations.^14,15,16 Slightly less evidence is found overall for an association with bronchitis, with Peters reporting a weak negative association, while others show evidence (mostly weak) of a positive association.^14,15,16,17 Estimates of associations with asthma and wheeze have been small and therefore, although varying in direction, not inconsistent with each other.^{14,15,16,17,18,19,20} Gauderman reports associations between asthma and measured NO₂, and between asthma and residence close to freeways, where traffic levels are extremely high, but no association with residence close to ordinary roads.²¹In the atmosphere, NO₂ is correlated with other pollutants including PM₁₀ and PM_2.5, because of similar sources. Pollutants'' independent effects are infrequently reported, because of their intercorrelations. Fusco found some independent NO₂ effect on acute respiratory infections.²² Braga found independent PM₁₀ effects only.²³ Some reported NO₂ effects may be due to associations with other pollutants such as ultrafine particles or diesel soot.The Pollution and the Young (PATY) project assembled health and exposure data for 58 561 children, from comparable cross sectional studies conducted in 12 countries. Pooling original data allows harmonisation of analysis, pursuit of research questions not addressed originally, and inclusion of unpublished studies. Here we examine associations between NO₂ and symptoms, in those PATY studies with NO₂ exposure data: 23 955 children aged 6–12, from five countries. We present results from single‐ and multipollutant models, exploiting the opportunity this pooled study gives to attempt to assess effects of NO₂, adjusted for other major pollutants (SO₂ and PM10). We further make use of the large dataset to assess effect modification with more precision than single studies.     

A Pilot Randomized Trial of a Companion Robot for People With Dementia Living in the Community

Objectives

To investigate the affective, social, behavioral, and physiological effects of the companion robot Paro for people with dementia in both a day care center and a home setting.

Airborne Endotoxin Concentrations in Homes Burning Biomass Fuel

Background

About half of the world’s population is exposed to smoke from burning biomass fuels at home. The high airborne particulate levels in these homes and the health burden of exposure to this smoke are well described. Burning unprocessed biological material such as wood and dried animal dung may also produce high indoor endotoxin concentrations.

Objective

In this study we measured airborne endotoxin levels in homes burning different biomass fuels.

Methods

Air sampling was carried out in homes burning wood or dried animal dung in Nepal (n = 31) and wood, charcoal, or crop residues in Malawi (n = 38). Filters were analyzed for endotoxin content expressed as airborne endotoxin concentration and endotoxin per mass of airborne particulate.

Results

Airborne endotoxin concentrations were high. Averaged over 24 hr in Malawian homes, median concentrations of total inhalable endotoxin were 24 endotoxin units (EU)/m³ in charcoal-burning homes and 40 EU/m³ in wood-burning homes. Short cooking-time samples collected in Nepal produced median values of 43 EU/m³ in wood-burning homes and 365 EU/m³ in dung-burning homes, suggesting increasing endotoxin levels with decreasing energy levels in unprocessed solid fuels.

Conclusions

Airborne endotoxin concentrations in homes burning biomass fuels are orders of magnitude higher than those found in homes in developed countries where endotoxin exposure has been linked to respiratory illness in children. There is a need for work to identify the determinants of these high concentrations, interventions to reduce exposure, and health studies to examine the effects of these sustained, near-occupational levels of exposure experienced from early life.     

Feasibility of assessing public health impacts of air pollution reduction programs on a local scale: New Haven case study

Background

New approaches to link health surveillance data with environmental and population exposure information are needed to examine the health benefits of risk management decisions.

Objective

We examined the feasibility of conducting a local assessment of the public health impacts of cumulative air pollution reduction activities from federal, state, local, and voluntary actions in the City of New Haven, Connecticut (USA).

Methods

Using a hybrid modeling approach that combines regional and local-scale air quality data, we estimated ambient concentrations for multiple air pollutants [e.g., PM_2.5 (particulate matter ≤ 2.5 μm in aerodynamic diameter), NO_x (nitrogen oxides)] for baseline year 2001 and projected emissions for 2010, 2020, and 2030. We assessed the feasibility of detecting health improvements in relation to reductions in air pollution for 26 different pollutant–health outcome linkages using both sample size and exploratory epidemiological simulations to further inform decision-making needs.

Results

Model projections suggested decreases (~ 10–60%) in pollutant concentrations, mainly attributable to decreases in pollutants from local sources between 2001 and 2010. Models indicated considerable spatial variability in the concentrations of most pollutants. Sample size analyses supported the feasibility of identifying linkages between reductions in NO_x and improvements in all-cause mortality, prevalence of asthma in children and adults, and cardiovascular and respiratory hospitalizations.

Conclusion

Substantial reductions in air pollution (e.g., ~ 60% for NO_x) are needed to detect health impacts of environmental actions using traditional epidemiological study designs in small communities like New Haven. In contrast, exploratory epidemiological simulations suggest that it may be possible to demonstrate the health impacts of PM reductions by predicting intraurban pollution gradients within New Haven using coupled models.     

Local determinants of road traffic noise levels versus determinants of air pollution levels in a Mediterranean city

Background

Both traffic-related noise and air pollution have been associated with cardiovascular disease (CVD). Spatial correlations between these environmental stressors may entail mutual confounding in epidemiological studies investigating their long-term effects. Few studies have investigated their correlation – none in Spain – and results differ among cities.

Objectives

We assessed the contribution of urban land-use and traffic variables to the noise–air pollution correlation in Girona town, where an investigation of the chronic effects of air pollution and noise on CVD takes place (REGICOR-AIR).

Methodology

Outdoor annual mean concentrations of nitrogen dioxide (NO₂) derived from monthly passive sampler measurements were obtained at 83 residential locations. Long-term average traffic-related noise levels from a validated model were assigned to each residence. Linear regression models were fitted both for NO₂ and noise.

Results

The correlation between NO₂ and noise (L_{24 h}) was 0.62. However, the correlation differed across the urban space, with lower correlations at sites with higher traffic density and in the modern downtown. Traffic density, distance from the location to the sidewalk and building density nearby explained 35.6% and 73.2% of the variability of NO₂ and noise levels, respectively. The correlation between the residuals of the two models suggested the presence of other unmeasured common variables.

Conclusions

The substantial correlation between traffic-related noise and NO₂, endorsed by common determinants, and the dependence of this correlation on complex local characteristics call for careful evaluations of both factors to ultimately assess their cardiovascular effects.     

Association between GIS-Based Exposure to Urban Air Pollution during Pregnancy and Birth Weight in the INMA Sabadell Cohort

Background

There is growing evidence that traffic-related air pollution reduces birth weight. Improving exposure assessment is a key issue to advance in this research area.

Objective

We investigated the effect of prenatal exposure to traffic-related air pollution via geographic information system (GIS) models on birth weight in 570 newborns from the INMA (Environment and Childhood) Sabadell cohort.

Methods

We estimated pregnancy and trimester-specific exposures to nitrogen dioxide and aromatic hydrocarbons [benzene, toluene, ethylbenzene, m/p-xylene, and o-xylene (BTEX)] by using temporally adjusted land-use regression (LUR) models. We built models for NO₂ and BTEX using four and three 1-week measurement campaigns, respectively, at 57 locations. We assessed the relationship between prenatal air pollution exposure and birth weight with linear regression models. We performed sensitivity analyses considering time spent at home and time spent in nonresidential outdoor environments during pregnancy.

Results

In the overall cohort, neither NO₂ nor BTEX exposure was significantly associated with birth weight in any of the exposure periods. When considering only women who spent < 2 hr/day in nonresidential outdoor environments, the estimated reductions in birth weight associated with an interquartile range increase in BTEX exposure levels were 77 g [95% confidence interval (CI), 7–146 g] and 102 g (95% CI, 28–176 g) for exposures during the whole pregnancy and the second trimester, respectively. The effects of NO₂ exposure were less clear in this subset.

Conclusions

The association of BTEX with reduced birth weight underscores the negative role of vehicle exhaust pollutants in reproductive health. Time–activity patterns during pregnancy complement GIS-based models in exposure assessment.     

Influences on Parents’ Child Care Choices: A Comparative Analysis of Preschool and Long Day Care Users

Background

This paper investigates Australian parents’ child care decision-making, including the motivational and influential factors that they attribute to their choice. Research demonstrates that child care decision making is multifaceted, involving a combination of child-related, personal, familial and contextual considerations. Existing research has tended to compare centre-based child care users with those using family-based options, and has not examined differences in the decision-making of parents who using different centre-based options.

Objective

This study compared the characteristics and child care choices of parents using long day care (LDC) with those using preschool services to determine (1) whether they differ demographically and (2) if their reported child care decision-making motivations and influences diverge.

Method

Participants were 1418 parents who completed a nationally-distributed survey in which they provided demographic information, specified their reasons for choosing to use child care, and rated the importance of factors that influenced their child care choice.

Results

LDC parents had, on average, younger children, worked longer hours and resided in areas with lower socioeconomic resources than preschool parents. When compared with preschool parents, those using LDC were more likely to nominate pragmatic factors as influencing their child care decision making. External pressures, mainly related to educational outcomes, were more salient for preschool than LDC parents. However, both groups of parents similarly rated child-centred factors as the most important overall influence.

Conclusion

Our findings add complexity to current understandings of parents’ child care decision making by showing that parents should not be treated as a homogenous group by policy makers, providers, and researchers.

     

Reducing burden of disease from residential indoor air exposures in Europe (HEALTHVENT project)

Background

The annual burden of disease caused indoor air pollution, including polluted outdoor air used to ventilate indoor spaces, is estimated to correspond to a loss of over 2 million healthy life years in the European Union (EU). Based on measurements of the European Environment Agency (EEA), approximately 90 % of EU citizens live in areas where the World Health Organization (WHO) guidelines for air quality of particulate matter sized?<?2.5 mm (PM_2.5) are not met. Since sources of pollution reside in both indoor and outdoor air, selecting the most appropriate ventilation strategy is not a simple and straightforward task.

Methods

A framework for developing European health-based ventilation guidelines was created in 2010–2013 in the EU-funded HEALTHVENT project. As a part of the project, the potential efficiency of control policies to health effects caused by residential indoor exposures of fine particulate matter (PM_2.5), outdoor bioaerosols, volatile organic compounds (VOC), carbon oxide (CO) radon and dampness was estimated. The analysis was based on scenario comparison, using an outdoor-indoor mass-balance model and varying the ventilation rates. Health effects were estimated with burden of diseases (BoD) calculations taking into account asthma, cardiovascular (CV) diseases, acute toxication, respiratory infections, lung cancer and chronic obstructive pulmonary disease (COPD).

Results

The quantitative comparison of three main policy approaches, (i) optimising ventilation rates only; (ii) filtration of outdoor air; and (iii) indoor source control, showed that all three approaches are able to provide substantial reductions in the health risks, varying from approximately 20 % to 44 %, corresponding to 400 000 and 900 000 saved healthy life years in EU-26. PM_2.5 caused majority of the health effects in all included countries, but the importance of the other pollutants varied by country.

Conclusions

The present modelling shows, that combination of controlling the indoor air sources and selecting appropriate ventilation rate was the most effective to reduce health risks. If indoor sources cannot be removed or their emissions cannot be limited to an accepted level, ventilation needs to be increased to remove remaining pollutants. In these cases filtration of outdoor air may be needed to prevent increase of health risks.

     

Traffic-Related Particulate Matter and Acute Respiratory Symptoms among New York City Area Adolescents

Background

Exposure to traffic-related particulate matter (PM) has been associated with adverse respiratory health outcomes in children. Diesel exhaust particles (DEPs) are a local driver of urban fine PM [aerodynamic diameter ≤ 2.5 μm (PM_2.5)]; however, evidence linking ambient DEP exposure to acute respiratory symptoms is relatively sparse, and susceptibilities of urban and asthmatic children are inadequately characterized.

Objectives

We examined associations of daily ambient black carbon (BC) concentrations, a DEP indicator, with daily respiratory symptoms among asthmatic and nonasthmatic adolescents in New York City (NYC) and a nearby suburban community.

Methods

BC and PM_2.5 were monitored continuously outside three NYC high schools and one suburban high school for 4–6 weeks, and daily symptom data were obtained from 249 subjects (57 asthmatics, 192 nonasthmatics) using diaries. Associations between pollutants and symptoms were characterized using multilevel generalized linear mixed models, and modification by urban residence and asthma status were examined.

Results

Increases in BC were associated with increased wheeze, shortness of breath, and chest tightness. Multiple lags of nitrogen dioxide (NO₂) exposure were associated with symptoms. For several symptoms, associations with BC and NO₂ were significantly larger in magnitude among urban subjects and asthmatics compared with suburban subjects and nonasthmatics, respectively. PM_2.5 was not consistently associated with increases in symptoms.

Conclusions

Acute exposures to traffic-related pollutants such as DEPs and/or NO₂ may contribute to increased respiratory morbidity among adolescents, and urban residents and asthmatics may be at increased risk. The findings provide support for developing additional strategies to reduce diesel emissions further, especially in populations susceptible because of environment or underlying respiratory disease.     

Comparing exposure assessment methods for traffic-related air pollution in an adverse pregnancy outcome study

Background

Previous studies reported adverse impacts of traffic-related air pollution exposure on pregnancy outcomes. Yet, little information exists on how effect estimates are impacted by the different exposure assessment methods employed in these studies.

Objectives

To compare effect estimates for traffic-related air pollution exposure and preeclampsia, preterm birth (gestational age less than 37 weeks), and very preterm birth (gestational age less than 30 weeks) based on four commonly used exposure assessment methods.

Methods

We identified 81,186 singleton births during 1997–2006 at four hospitals in Los Angeles and Orange Counties, California. Exposures were assigned to individual subjects based on residential address at delivery using the nearest ambient monitoring station data [carbon monoxide (CO), nitrogen dioxide (NO₂), nitric oxide (NO), nitrogen oxides (NO_x), ozone (O₃), and particulate matter less than 2.5 (PM_2.5) or less than 10 (PM₁₀) μm in aerodynamic diameter], both unadjusted and temporally adjusted land-use regression (LUR) model estimates (NO, NO₂, and NO_x), CALINE4 line-source air dispersion model estimates (NO_x and PM_2.5), and a simple traffic-density measure. We employed unconditional logistic regression to analyze preeclampsia in our birth cohort, while for gestational age-matched risk sets with preterm and very preterm birth we employed conditional logistic regression.

Results

We observed elevated risks for preeclampsia, preterm birth, and very preterm birth from maternal exposures to traffic air pollutants measured at ambient stations (CO, NO, NO₂, and NO_x) and modeled through CALINE4 (NO_x and PM_2.5) and LUR (NO₂ and NO_x). Increased risk of preterm birth and very preterm birth were also positively associated with PM₁₀ and PM_2.5 air pollution measured at ambient stations. For LUR-modeled NO₂ and NO_x exposures, elevated risks for all the outcomes were observed in Los Angeles only—the region for which the LUR models were initially developed. Unadjusted LUR models often produced odds ratios somewhat larger in size than temporally adjusted models. The size of effect estimates was smaller for exposures based on simpler traffic density measures than the other exposure assessment methods.

Conclusion

We generally confirmed that traffic-related air pollution was associated with adverse reproductive outcomes regardless of the exposure assessment method employed, yet the size of the estimated effect depended on how both temporal and spatial variations were incorporated into exposure assessment. The LUR model was not transferable even between two contiguous areas within the same large metropolitan area in Southern California.