Indoor exposures to air pollutants and allergens in the homes of asthmatic children in inner-city Baltimore

Effects of prenatal polycyclic aromatic hydrocarbons and childhood material hardship on reading achievement in school-age children: A preliminary study

Background

Children from socioeconomically disadvantaged backgrounds are at elevated risk for reading problems. They are also likely to live in neighborhoods with high levels of air pollution and to experience material hardship. Despite these risk factors, the links between prenatal chemical exposures, socioeconomic adversities, and reading problems in youth from disadvantaged backgrounds remain understudied. Here we examine associations between prenatal exposure to polycyclic aromatic hydrocarbons (PAH), a common air pollutant, and reading skills, and determine if this relationship is exacerbated by material hardship among Black and/or Latinx children who have been followed as part of a longitudinal urban birth cohort.

Methods

Mothers and their children, who were participants in a prospective birth cohort followed by the Columbia Center for Children's Environmental Health, were recruited for the current study. Personal prenatal PAH exposure was measured during the third-trimester of pregnancy using a personal air monitoring backpack. Mothers reported their level of material hardship when their child was age 5 and children completed measures of pseudoword and word reading [Woodcock Johnson III Tests of Achievement (WJ-III) Basic Reading Index] at age 7. We used multiple linear regression to examine the effects of the interaction between prenatal PAH and material hardship on Basic Reading Index, controlling for ethnicity/race, sex, birthweight, presence of a smoker in the home (prenatal), and maternal education (prenatal) (N = 53).

Results

A prenatal PAH × material hardship interaction significantly associated with WJ-III Basic Reading Index scores at age 7 (β = -0.347, t(44) = -2.197, p = 0.033). Exploratory analyses suggested that this effect was driven by untimed pseudoword decoding (WJ-III Word Attack: β = -0.391, t(44) = -2.550, p = 0.014).

Conclusion

Environmental chemical exposures can be particularly toxic during the prenatal period when the fetal brain undergoes rapid development, making it uniquely vulnerable to chemical perturbations. These data highlight the interactive effects of environmental neurotoxicants and unmet basic needs on children's acquisition of reading skill, specifically phonemic processing. Such findings identify potentially modifiable environmental risk factors implicated in reading problems in children from economically disadvantaged backgrounds.

Effects of Ambient Air Pollution on Precocious Puberty: A Case-Crossover Analysis in Nanjing, China

BACKGROUND

Ambient air pollution is closely related to a variety of health outcomes. Few studies have focused on the correlations between air pollution exposure and children's sexual development. In this study, we investigated the potential effects of exposure to air pollution on precocious puberty among children using real-world evidence.

METHODS

We conducted a case-crossover study (n = 2201) to investigate the effect of ambient air pollution exposure on precocious puberty from January 2016 to December 2021. Average exposure levels of PM_2.5, PM₁₀, SO₂, NO₂, CO, and O₃ before diagnosis were calculated by using the inverse distance weighting (IDW) method. Distributed lag nonlinear model (DLNM) was used to assess the effect of air pollutants exposure on precocious puberty.

RESULTS

The mean age of the children who were diagnosed with precocious puberty was 7.47 ± 1.24 years. The average concentration of PM_2.5 and PM₁₀ were 38.81 ± 26.36 μg/m³ and 69.77 ± 41.07 μg/m³, respectively. We found that exposure to high concentrations of PM_2.5 and PM₁₀ might increase the risk of precocious puberty using the DLNM model adjusted for the age, SO₂, NO₂, CO, and O₃ levels. The strongest effects of the PM_2.5 and PM₁₀ on precocious puberty were observed in lag 27 (OR = 1.72, 95% CI: 1.01-2.92) and lag 16 (OR = 1.95, 95% CI: 1.33-2.85), respectively.

CONCLUSION

Our findings supported that short-term exposure to air pollution was the risk factor for precocious puberty. Every effort should be made to protect children from air pollution.

Ambient ozone effects on respiratory outcomes among smokers modified by neighborhood poverty: An analysis of SPIROMICS AIR

BACKGROUND

Neighborhood poverty has been associated with poor health outcomes. Previous studies have also identified adverse respiratory effects of long-term ambient ozone. Factors associated with neighborhood poverty may accentuate the adverse impact of ozone on respiratory health.

OBJECTIVES

To evaluate whether neighborhood poverty modifies the association between ambient ozone exposure and respiratory morbidity including symptoms, exacerbation risk, and radiologic parameters, among participants of the SPIROMICS AIR cohort study.

METHODS

Spatiotemporal models incorporating cohort-specific monitoring estimated 10-year average outdoor ozone concentrations at participants' homes. Adjusted regression models were used to determine the association of ozone exposure with respiratory outcomes, accounting for demographic factors, education, individual income, body mass index (BMI), and study site. Neighborhood poverty rate was defined by percentage of families living below federal poverty level per census tract. Interaction terms for neighborhood poverty rate with ozone were included in covariate-adjusted models to evaluate for effect modification.

RESULTS

1874 participants were included in the analysis, with mean (± SD) age 64 (± 8.8) years and FEV₁ (forced expiratory volume in one second) 74.7% (±25.8) predicted. Participants resided in neighborhoods with mean poverty rate of 9.9% (±10.3) of families below the federal poverty level and mean 10-year ambient ozone concentration of 24.7 (±5.2) ppb. There was an interaction between neighborhood poverty rate and ozone concentration for numerous respiratory outcomes, including COPD Assessment Test score, modified Medical Research Council Dyspnea Scale, six-minute walk test, and odds of COPD exacerbation in the year prior to enrollment, such that adverse effects of ozone were greater among participants in higher poverty neighborhoods.

CONCLUSION

Individuals with COPD in high poverty neighborhoods have higher susceptibility to adverse respiratory effects of ambient ozone exposure, after adjusting for individual factors. These findings highlight the interaction between exposures associated with poverty and their effect on respiratory health.

Evaluation of indoor PM2.5 concentrations in a Native American Community: a pilot study

BACKGROUND

Indoor air pollution is associated with adverse health effects; however, few studies exist studying indoor air pollution on the Navajo Nation in the southwest U.S., a community with high rates of respiratory disease.

METHODS

Indoor PM_2.5 concentration was evaluated in 26 homes on the Navajo Nation using real-time PM_2.5 monitors. Household risk factors and daily activities were evaluated with three metrics of indoor PM_2.5: time-weighted average (TWA), 90th percentile of concentration, and daily minutes exceeding 100 μg/m³. A questionnaire and recall sheet were used to record baseline household characteristics and daily activities.

RESULTS

The median TWA, 90th percentile, and daily minutes exceeding 100 μg/m³ were 7.9 μg/m³, 14.0 μg/m³_, and 17 min, respectively. TWAs tended to be higher in autumn and in houses that used fuel the previous day. Other characteristics associated with elevated PM exposure in all metrics included overcrowded houses, nonmobile houses, and houses with current smokers, pets, and longer cooking time.

CONCLUSIONS

Some residents of the Navajo Nation have higher risk of exposure to indoor air pollution by Environmental Protection Agency (EPA) standards. Efforts to identify the causes and associations with adverse health effects are needed to ensure that exposure to risks and possible health impacts are mitigated.

Effectiveness of portable HEPA air cleaners on reducing indoor endotoxin, PM10, and coarse particulate matter in an agricultural cohort of children with asthma: A randomized intervention trial

We conducted a randomized trial of portable HEPA air cleaners in the homes of children age 6-12 years with asthma in the Yakima Valley, Washington. All families received asthma education while intervention families also received two HEPA cleaners (child's bedroom, living room). We collected 14-day integrated samples of endotoxin in settled dust and PM₁₀ and PM_10-2.5 in the air of the children's bedrooms at baseline and one-year follow-up, and used linear regression to compare follow-up levels, adjusting for baseline. Seventy-one families (36 HEPA, 35 control) completed the study. Baseline geometric mean (GSD) endotoxin loadings were 1565 (6.3) EU/m² and 2110 (4.9) EU/m² , respectively, in HEPA vs. control homes while PM₁₀ and PM_10-2.5 were 22.5 (1.9) μg/m³ and 9.5 (2.9) μg/m³ , respectively, in HEPA homes, and 19.8 (1.8) μg/m³ and 7.7 (2.0) μg/m³ , respectively, in control homes. At follow-up, HEPA families had 46% lower (95% CI, 31%-57%) PM₁₀ on average than control families, consistent with prior studies. In the best-fit heterogeneous slopes model, HEPA families had 49% (95% CI, 6%-110%) and 89% lower (95% CI, 28%-177%) PM_10-2.5 at follow-up, respectively, at 50th and 75th percentile baseline concentrations. Endotoxin loadings did not differ significantly at follow-up (4% lower, HEPA homes; 95% CI, -87% to 50%).

Indoor Air Pollution and Respiratory Health

Worldwide, more than 4 million deaths annually are attributed to indoor air pollution. This largely preventable exposure represents a key target for reducing morbidity and mortality worldwide. Significant respiratory health effects are observed, ranging from attenuated lung growth and development in childhood to accelerated lung function decline and is determined by chronic obstructive pulmonary disease later in life. Personal exposure to household air pollutants include household characteristics, combustion of solid fuels, cooking practices, and household pest allergens. This review outlines important sources of indoor air pollution, their respiratory health effects, and strategies to reduce household pollution and improve lung health across the globe.

Source identification of heavy metals and stable carbon isotope in indoor dust from different functional areas in Hefei, China

Dust on air conditioning filters can represent the re-suspended particulate matter in indoor air, which may pose potential health risks to humans. However, source identification and influence factors of indoor dust are controversial. The present study investigated the distribution of Cd, Cr, Mn, Ni, Pb, Sb, V, and Zn, as well as stable carbon isotope, in indoor dust from three different functional zones in Hefei to discuss the sources and influence factors of indoor dust. PCA analysis of heavy metals showed that indoor sources (such as cooking and smoking) were the main sources. Negative correlation appeared between family size and heavy metal concentrations. This was because people acted as a sink of pollutants. Concentration analysis of heavy metals revealed that smoking and cooking had weak relevance with heavy metal concentrations. While through the δ¹³C analysis, cooking had a significant correlation with δ¹³C of indoor dust, instructing that cooking was a significant source of indoor dust. Besides, smoking also had a certain correlation with δ¹³C of indoor dust, instructing that smoking was one of the sources of indoor dust.

Reduction in mouse allergen exposure is associated with greater lung function growth

BACKGROUND

Current childhood asthma therapies have little effect on lung function trajectory.

OBJECTIVE

We sought to determine whether mouse allergen exposure reduction is associated with lung function growth in mouse-sensitized/exposed asthmatic children.

METHODS

Three hundred fifty mouse-sensitized/exposed asthmatic children (5-17 years old) were enrolled in a 1-year randomized trial of integrated pest management plus education versus education alone. Prebronchodilator/postbronchodilator spirometry was performed at baseline and 6 and 12 months, and bedroom floor mouse allergen levels were measured every 3 months. Mouse allergen reduction was defined as a 75% or greater decrease in mouse allergen levels from baseline. Treatment groups were combined for analyses because there were no differences in outcomes between groups. Changes in lung function over time were modeled, adjusting for age, sex, race, atopy, group, and bronchodilator reversibility and including an interaction term (allergen reduction*time).

RESULTS

The study population was predominantly black (79.4%) and low income (66.3% [<$30,000]). At baseline, the median mouse allergen level was 5.7 μg/g (interquartile range, 1.5-22.8 μg/g), and the mean (SD) prebronchodilator FEV₁/forced vital capacity ratio was 80.2% (9.0%). Ninety-two (26.3%) participants had 75% or greater reduction in mouse allergen levels. For a 10-year-old black boy, 75% or greater allergen reduction was associated with an increase in prebronchodilator FEV₁ of 238 mL/y (95% CI, 177-299 mL/y), whereas less than 75% allergen reduction was associated with an increase in prebronchodilator FEV₁ of 131 mL/y (95% CI, 97-166 mL/y). Estimated differences in prebronchodilator and postbronchodilator FEV₁ growth were as follows: 107 mL/y (95% CI, 37-177 mL/y; P_int = .003) and 48 mL/y (95% CI, -17 to 113 mL/y; P_int = .15), respectively. Estimated differences in prebronchodilator and postbronchodilator forced expiratory flow at 25% to 75% of vital capacity growth were as follows: 182 mL/y (95% CI, 61-304 mL/y; P_int = .003) and 181 mL/y (95% CI, 48-314 mL/y; P_int = .008), respectively.

CONCLUSION

Mouse allergen reduction is associated with greater increases in prebronchodilator FEV₁ and prebronchodilator/postbronchodilator forced expiratory flow at 25% to 75% of vital capacity over 1 year among sensitized/exposed asthmatic children.

Role of location, season, occupant activity, and chemistry in indoor ozone and nitrogen oxide mixing ratios

Understanding the oxidizing environment indoors is important for predicting indoor air quality and its impact on human health. We made continuous time-resolved measurements (30 s) of several oxidants and oxidant precursors (collectively referred to as oxidant*): ozone (O3), nitric oxide (NO), and NO2* - the sum of nitrogen dioxide (NO2) and nitrous acid (HONO). These species were measured in three indoor environments - an occupied residence, a chemistry laboratory, and an academic office - in Syracuse, New York, during two seasons in 2017 and 2018. Oxidant* levels differed greatly between the residence, the lab and the office. Indoor-to-outdoor ratios (I/O) of O3 were 0.03 and 0.67 in the residence and office; I/ONO (I/ONO2*) were 11.70 (1.26) in the residence and 0.13 (1.70) in the office. Little seasonal variability was observed in the lab and office, but O3 and NO2* levels in the residence were greater in spring than in winter, while NO levels were lower. Human activities such as cooking and opening patio doors resulted in large changes in oxidant* mixing ratios in the residence. In situ chamber experiments demonstrated that the increase in O3 and NO2* levels during door-open periods was due to a combination of physical mixing between indoor and outdoor air, gas-phase production of NO2 from O3-NO chemistry, and heterogeneous formation of HONO on indoor surfaces. Our results also highlight the importance of chemistry (with NO, alkenes, and surfaces) in O3 mixing ratios in the residence, especially during door-open periods.

Illuminating the dark side of indoor oxidants

The chemistry of oxidants and their precursors (oxidants*) plays a central role in outdoor environments but its importance in indoor air remains poorly understood. Ozone (O3) chemistry is important in some indoor environments and, until recently, ozone was thought to be the dominant oxidant indoors. There is now evidence that formation of the hydroxyl radical by photolysis of nitrous acid (HONO) and formaldehyde (HCHO) may be important indoors. In the past few years, high time-resolution measurements of oxidants* indoors have become more common and the importance of event-based release of oxidants* during activities such as cleaning has been proposed. Here we review the current understanding of oxidants* indoors, including drivers of the formation and loss of oxidants*, levels of oxidants* in indoor environments, and important directions for future research.

Omega-3 and Omega-6 Intake Modifies Asthma Severity and Response to Indoor Air Pollution in Children

Rationale: Higher indoor particulate matter (PM) concentrations are linked with increased asthma morbidity. Dietary intake of fatty acids, also linked with asthma outcomes, may influence this relationship. Objectives: To determine the relationship between omega-3 and omega-6 fatty acid intake and pediatric asthma morbidity, and the association between fatty acid intake and strength of indoor, PM-related asthma symptoms, albuterol use, and systemic inflammation. Methods: Analyses included 135 children with asthma enrolled in the AsthmaDIET Study. At baseline, 3 months, and 6 months, data included: week-long average home indoor concentration of PM ≤2.5 μm in aerodynamic diameter and PM ≤10 μm in aerodynamic diameter, dietary intake of omega-3 and omega-6 fatty acids, daily symptoms, and peripheral blood leukocytes. Asthma severity and lung function were assessed at baseline. Multivariable regression models, adjusted for known confounders, were used to determine associations between each fatty acid and outcomes of interest, with interaction terms (fatty acids × PM) in longitudinal analyses. Measurements and Main Results: Higher omega-6 intake associated with increased odds of increased asthma severity (P = 0.02), and lower FEV1/FVC ratio (P = 0.01). Higher omega-3 intake associated with reduced effect of indoor PM ≤2.5 μm in aerodynamic diameter on symptoms (P < 0.01), whereas higher omega-6 intake associated with amplified effect of indoor PM ≤2.5 μm in aerodynamic diameter on symptoms and circulating neutrophil percentage (P < 0.01). Conclusions: Omega-3 and omega-6 intake are associated with pediatric asthma morbidity and may modify the asthmatic response to indoor PM.

Indoor air quality in inner-city schools and its associations with building characteristics and environmental factors

Indoor concentrations of fine particulate matter (PM_2.5), nitrogen dioxide (NO₂), and carbon monoxide (CO) were measured across 16 urban public schools in three different seasons. Exceedance of the WHO guidelines for indoor air was observed, mainly for the hourly average NO₂ concentrations. Seasonal variability was statistically significant for indoor NO₂ and CO concentrations, with higher exposures in fall and winter. An extensive list of potential factors at the outdoor environment, school, and room level that may explain the variability in indoor exposure was examined. Factors with significant contributions to indoor exposure were mostly related to the outdoor pollution sources. This is evidenced by the strong associations between indoor concentration of CO and NO₂ and factors including outdoor PM_2.5 and NO₂ concentrations, including length of the nearby roads and the number of nearby industrial facilities. Additionally, we found that poor conditions of the buildings (a prevalent phenomenon in the studied urban area), including physical defects and lack of proper ventilation, contributed to poor air quality in schools. The results suggest that improving building conditions and facilities as well as a consideration of the school surroundings may improve indoor air quality in schools.

The Fort Collins commuter study: Variability in personal exposure to air pollutants by microenvironment

This study investigated the role of microenvironment on personal exposures to black carbon (BC), fine particulate mass (PM2.5 ), carbon monoxide (CO), and particle number concentration (PNC) among adult residents of Fort Collins, Colorado, USA. Forty-four participants carried a backpack containing personal monitoring instruments for eight nonconsecutive 24-hour periods. Exposures were apportioned into five microenvironments: Home, Work, Transit, Eateries, and Other. Personal exposures exhibited wide heterogeneity that was dominated by within-person variability (both day-to-day and between microenvironment variability). Linear mixed-effects models were used to compare mean personal exposures in each microenvironment, while accounting for possible within-person correlation. Mean personal exposures during Transit and at Eateries tended to be higher than exposures at Home, where participants spent the majority of their time. Compared to Home, mean exposures to BC in Transit were, on average, 129% [95% confidence interval: 101% 162%] higher and exposures to PNC were 180% [101% 289%] higher in Eateries.

Sampling Devices for Indoor Allergen Exposure: Pros and Cons

PURPOSE OF REVIEW

To review current indoor allergen sampling devices, including devices to measure allergen in reservoir and airborne dust, and personal sampling devices, with attention to sampling rationale and major indoor allergen size and characteristics.

RECENT FINDINGS

While reservoir dust vacuuming samples and airborne dust volumetric air sampling remain popular techniques, recent literature describes sampling using furnace filters and ion-charging devices, both which help to eliminate the need for trained staff; however, variable correlation with reservoir dust and volumetric air sampling has been described. Personal sampling devices include intra-nasal samples and personal volumetric air samples. While these devices may offer better estimates of breathable allergens, they are worn for short periods of time and can be cumbersome. Reservoir dust sampling is inexpensive and is possible for families to perform. Airborne dust sampling can be more expensive and may better quantify cat, dog, and mouse allergen exposure. Personal sampling devices may offer a better representation of breathable air.

Time-Resolved Measurements of Nitric Oxide, Nitrogen Dioxide, and Nitrous Acid in an Occupied New York Home

Indoor oxidizing capacity in occupied residences is poorly understood. We made simultaneous continuous time-resolved measurements of ozone (O₃), nitric oxide (NO), nitrogen dioxide (NO₂), and nitrous acid (HONO) for two months in an occupied detached home with gas appliances in Syracuse, NY. Indoor NO and HONO mixing ratios were higher than those outdoors, whereas O₃ was much lower (sub-ppbv) indoors. Cooking led to peak NO, NO₂, and HONO levels 20-100 times greater than background levels; HONO mixing ratios of up to 50 ppbv were measured. Our results suggest that many reported NO₂ levels may have a large positive bias due to HONO interference. Nitrous acid, NO₂, and NO were removed from indoor air more rapidly than CO₂, indicative of reactive removal processes or surface uptake. We measured spectral irradiance from sunlight entering the residence through glass doors; hydroxyl radical (OH) production rates of (0.8-10) × 10⁷ molecules cm^-3 s^-1 were calculated in sunlit areas due to HONO photolysis, in some cases exceeding rates expected from ozone-alkene reactions. Steady-state nitrate radical (NO₃) mixing ratios indoors were predicted to be lower than 1.65 × 10⁴ molecules cm^-3. This work will help constrain the temporal nature of oxidant concentrations in occupied residences and will improve indoor chemistry models.

Maternal exposure to PM2.5 in south Texas, a pilot study

In this study, we characterized personal exposure to fine particulate matter (PM_2.5), black carbon (BC), and nicotine in pregnant women in Hidalgo County, where the hospitalization rates of childhood asthma are the highest in the state of Texas. The measurements were conducted over three non-consecutive sampling days for 17 participants in their third trimester. Measurements were partitioned into four microenvironments, i.e., Residential, Vehicular, Commercial, and Other, on the basis of GPS coordinates and temperature and humidity measurements. The daily average PM_2.5 mass concentration was 24.2 (standard deviation=22.0) μg/m³, with the highest daily mass concentration reaching 126.0μg/m³. The daily average BC concentration was 1.44 (SD=0.82) μg/m³, ranging from 0.5 to 5.4μg/m³. Hair nicotine concentrations were all near the detection level (i.e., 49.2pg/mg), indicating that the participants were not routinely exposed to tobacco smoke. The Residential microenvironment contributed dominantly to the mass concentration since the participants chiefly remained at home and cooking activities contributed significantly to the total PM_2.5. When compared to an ambient monitoring station, the person-specific PM_2.5 was frequently more than double the ambient measurement (10.4μg/m³ overall), revealing that even in regions where ambient concentrations are below national standards, individuals may be still be exposed to elevated PM_2.5 mass concentrations.

The feasibility of an air purifier and secondhand smoke education intervention in homes of inner city pregnant women and infants living with a smoker

OBJECTIVES

Secondhand smoke (SHS) and other air pollutants adversely affect the health of pregnant women and infants. A feasibility study aimed at reducing air pollution in homes of pregnant women or infants living with a smoker was completed.

METHODS

In collaboration with the Baltimore City Health Department, women ≥ 18 years of age and either pregnant nonsmokers, or post-partum (any smoking status) with an infant age 0-12 months were recruited. Homes had at least one smoker. Intervention included two air purifiers and secondhand smoke education. Outcomes included feasibility, change in fine particulate matter (PM_2.5), air nicotine, and salivary cotinine pre- and post-intervention.

RESULTS

Fifty women were enrolled (mean age 27 years, 92% African American, 71% single, 94% Medicaid eligible, 34% reported smoking) and 86% completed the study. Of the 50 women, 32 had infants and 18 were pregnant at time of enrollment. Post- intervention, 70% of participants reported smokers were less likely to smoke indoors, and 77% had at least one air purifier turned on at the final visit. Participant satisfaction was high (91%) and 98% would recommend air purifiers. Indoor PM_2.5 was significantly decreased (P < 0.001). Salivary cotinine was significantly decreased for non-smoking women (P < 0.01) but not infants, and no significant change in air nicotine occurred (P = 0.6).

CONCLUSIONS

Air purifiers with SHS education is a feasible intervention in homes of women and infants. These data demonstrate reduction in indoor PM_2.5 and salivary cotinine in non-smoking adults. Air purifiers are not an alternative for smoking cessation and a home/ car smoking ban. Smoking cessation should be strongly encouraged for all pregnant women, and nonsmoking mothers with infants should be counseled to completely avoid SHS exposure. This study provides support for a future intervention evaluating clinical endpoints.

24-h Nitrogen dioxide concentration is associated with cooking behaviors and an increase in rescue medication use in children with asthma

Exposure to nitrogen dioxide (NO₂), a byproduct of combustion, is associated with poor asthma control in children. We sought to determine whether gas-fueled kitchen appliance use is associated with 24-h indoor NO₂ concentrations and whether these concentrations are associated with asthma morbidity in children. Children aged 5-12 years old with asthma were eligible. Mean 24-h NO₂ concentration was measured in the kitchen over a four-day sampling period and gas stove use was captured in time activity diaries. The relationship between stove and oven use and daily NO₂ concentration was analyzed. Longitudinal analysis assessed the effect of daily NO₂ exposure on symptoms, inhaler use, and lung function. Multivariate models were adjusted for age, sex, season, and maternal education. Thirty children contributed 126 participant days of sampling. Mean indoor 24-h NO₂ concentration was 58(48)ppb with a median (range) of 45(12-276)ppb. All homes had gas stoves and furnaces. Each hour of kitchen appliance use was associated with an 18ppb increase in 24-h NO₂ concentration. In longitudinal multivariate analysis, each ten-fold increase in previous-day NO₂ was associated with increased nighttime inhaler use (OR = 4.9, p = 0.04). There were no associations between NO₂ and lung function or asthma symptoms. Higher previous-day 24-h concentration of NO₂ is associated with increased nighttime inhaler use in children with asthma.

Mouse Sensitization and Exposure Are Associated with Asthma Severity in Urban Children

BACKGROUND

Mouse sensitization and exposure are associated with uncontrolled asthma, but whether they are associated with asthma severity, an intrinsic disease characteristic and long-term outcome predictor, is unclear.

OBJECTIVE

To examine relationships between mouse sensitization and/or exposure and asthma severity in urban children.

METHODS

A total of 645 children (5-17 years) with uncontrolled asthma underwent mouse sensitization evaluation. Sensitized children had mouse allergen measured in bedroom dust. Relationships between mouse sensitization, allergen levels, and asthma severity measures (treatment step and Composite Asthma Severity Index [CASI]) were examined using regression models adjusted for age, sex, atopy, study site, race, ethnicity, and insurance.

RESULTS

The study population was predominantly minority (69.6% black, 20.8% Hispanic), low income (61.8%), and mouse sensitized (54.4%). Mean ± SD treatment step was 3.2 ± 1.6, equivalent to medium-dose inhaled corticosteroid. Mean ± SD CASI was 6.5 ± 3.4, reflecting moderate persistent asthma. Mouse sensitization was associated with higher treatment step (3.5 vs 2.9, mouse-sensitized vs nonsensitized, P < .001), independent of potential confounders (β [95% CI], 0.36 [0.07-0.64]; P = .01). Mouse sensitization was associated independently with CASI (β [95% CI], 0.82 [0.16-1.47]; P = .02). Among mouse-sensitized participants, higher bedroom floor and bed Mus m 1 were independently associated with treatment step (β [95% CI], 0.26 [0.09-0.43]; P = .002 and β [95% CI], 0.22 [0.01-0.43]; P = .04), respectively. Higher bedroom floor Mus m 1 was independently associated with CASI (β [95% CI], 0.43 [0.05-0.81]; P = .03).

CONCLUSIONS

Mouse sensitization and exposure are associated with asthma severity, among low-income, minority children. Further studies are needed to determine whether reducing allergen exposure among mouse-sensitized patients with asthma can reduce severity, ultimately altering childhood asthma natural history.

Predictors of polycyclic aromatic hydrocarbon exposure and internal dose in inner city Baltimore children

Polycyclic aromatic hydrocarbons (PAHs), the by-products of incomplete combustion of organic materials, are commonly found on particulate matter (PM) and have been associated with the development of asthma and asthma exacerbation in urban populations. We examined time spent in the home and outdoors as predictors of exposures to airborne PAHs and measured urinary 1-hydroxypyrene-glucuronide (1-OHPG) as internal dose of PAHs in 118 children aged 5-12 years from Baltimore, MD. During weeklong periods (Saturday-Saturday) in each of four seasons: daily activities were assessed using questionnaires, indoor air nicotine and PM concentrations were monitored, and urine specimens were collected on Tuesday (day 3) and Saturday (day 7) for measurement of 1-OHPG. Time spent in non-smoking homes was associated with significantly decreased 1-OHPG concentration in urine (β=-0.045, 95% CI (-0.076, -0.013)), and secondhand smoke (SHS) exposures modified these associations, with higher urinary 1-OHPG concentrations in children spending time in smoking homes than non-smoking homes (P-value for interaction=0.012). Time spent outdoors was associated with increased urinary 1-OHPG concentrations (β=0.097, 95% CI (0.037, 0.157)) in boys only. Our results suggest that SHS and ambient (outdoor) air pollution contribute to internal dose of PAHs in inner city children.

Indoor pollutant exposure among children with and without asthma in Porto, Portugal, during the cold season

Considering the time spent in enclosed spaces, indoor air pollutants are of major interest because of its possible impact on health. However, to date, few studies have analysed the air concentrations of a large set of indoor pollutants of respiratory health relevance in dwellings, particularly in Portugal. This study aimed to measure the concentrations of air pollutants that are present in residential buildings and to investigate whether some clustering pattern of indoor air pollutants exists in the dwellings of children with (case group) and without asthma (control group). Measurements were taken in 30 and 38 dwellings of asthmatic and non-asthmatic schoolchildren, respectively, located in the city of Porto, Portugal, during the cold season (October 2012-April 2013), to assess the concentrations of 12 volatile organic compounds (VOC), aldehydes, PM_2.5, PM₁₀, bacteria and fungi. Toluene, d-limonene, formaldehyde, PM_2.5, bacteria and fungi are widely present in dwellings, sometimes in relatively high concentrations in reference to WHO guideline values. Moreover, concentrations of CO₂ exceeding 1000 ppm were often encountered, indicating that 70 % of all dwellings had poor ventilation (<4 L/s person). While exposures to common dwelling indoor pollutants are similar for schoolchildren with and without asthma, except for d-limonene levels, the identification and control of VOC and PM sources is important and prudent, especially for vulnerable individuals.

Indoor air risk factors for schoolchildren's health in Portuguese homes: Results from a case-control survey

Allergic diseases have been on the rise in many countries over the past few decades and indoor exposure may be a possible cause. An overall investigation of children's health status and residential indoor air pollutants known or suspected to affect respiratory health was conducted in the homes of primary schoolchildren during winter in Porto, Portugal. In a case-control study (30 case children with asthma and 38 controls) and over a 1-wk monitoring period, air sample collection was conducted in children's bedrooms for the analysis of 12 volatile organic compounds (VOC), aldehydes, particulate matter (PM)2.5, PM10, bacteria, and fungi. Home exposures to indoor pollutants are similar for children with and without asthma, except for d-limonene. For both groups, most VOC were present at low concentrations (median < 5 µg/m(3)) and below the respective World Health Organization (WHO) guidelines. Concentrations of PM2.5, PM10, and bacteria were frequently higher than WHO/reference values (80, 25, and 60% of all studied dwellings, respectively). Concentrations of carbon dioxide (CO2) exceeding 1000 ppm were encountered in 60% of the homes. Although this study does not provide evidence of causative factors for asthmatic status, the postulation that poor indoor air quality in homes heightens the risk of allergic symptoms development among children is conceivable.

Indoor air quality at life and work environments in Rome, Italy

The air quality of three different microenvironments (school, dwelling, and coffee bar) located in the city of Rome, Italy, was assessed. Indoor and outdoor concentrations of polycyclic aromatic hydrocarbons (PAHs) associated with PM2.5 particles were determined during an intensive 3-week sampling campaign conducted in March 2013. In interiors, total particulate PAHs ranged from 1.53 to 4.96 ng/m(3) while outdoor air contained from 2.75 to 3.48 ng/m(3). In addition, gaseous toxicants, i.e., NO2, NOx , SO2, O3, and BTEX (benzene, toluene, ethyl-benzene, and xylene isomers), were determined both in internal and external air. To solve the origin of indoor and outdoor PAHs, several source apportionment methods were applied. Multivariate analysis revealed that emissions from motor vehicles, biomass burning for heating purposes, and soil resuspension were the major sources of PAHs in the city. No linear correlation was established between indoor and outdoor values for PM2.5 and BTEX; the respective indoor/outdoor concentration ratios exceed unity except for PM2.5 in the no smoking home and benzene in all school floors. This suggests that important internal sources such as tobacco smoking, cleaning products, and resuspension dust contributed to indoor pollution. Using the monitoring stations of ARPA Lazio regional network as reference, the percentage within PAH group of benzo[a]pyrene, which is the WHO marker for the carcinogenic risk estimates, was ca. 50% higher in all locations investigated.

Association of Roadway Proximity with Indoor Air Pollution in a Peri-Urban Community in Lima, Peru

The influence of traffic-related air pollution on indoor residential exposure is not well characterized in homes with high natural ventilation in low-income countries. Additionally, domestic allergen exposure is unknown in such populations. We conducted a pilot study of 25 homes in peri-urban Lima, Peru to estimate the effects of roadway proximity and season on residential concentrations. Indoor and outdoor concentrations of particulate matter (PM_2.5), nitrogen dioxide (NO₂), and black carbon (BC) were measured during two seasons, and allergens were measured in bedroom dust. Allergen levels were highest for dust mite and mouse allergens, with concentrations above clinically relevant thresholds in over a quarter and half of all homes, respectively. Mean indoor and outdoor pollutant concentrations were similar (PM_2.5: 20.0 vs. 16.9 μg/m³, BC: 7.6 vs. 8.1 μg/m³, NO₂: 7.3 vs. 7.5 ppb), and tended to be higher in the summer compared to the winter. Road proximity was significantly correlated with overall concentrations of outdoor PM_2.5 (r_s = −0.42, p = 0.01) and NO₂ (r_s = −0.36, p = 0.03), and outdoor BC concentrations in the winter (r_s = −0.51, p = 0.03). Our results suggest that outdoor-sourced pollutants significantly influence indoor air quality in peri-urban Peruvian communities, and homes closer to roadways are particularly vulnerable.

Fine particulate matter concentrations in smoking households: just how much secondhand smoke do you breathe in if you live with a smoker who smokes indoors?

OBJECTIVE

Using data on fine particulate matter less than 2.5 μm (PM2.5) concentrations in smoking and non-smoking homes in Scotland to estimate the mass of PM2.5 inhaled by different age groups.

METHODS

Data from four linked studies, with real-time measurements of PM2.5 in homes, were combined with data on typical breathing rates and time-activity patterns. Monte Carlo modelling was used to estimate daily PM2.5 intake, the percentage of total PM2.5 inhaled within the home environment and the percentage reduction in daily intake that could be achieved by switching to a smoke-free home.

RESULTS

Median (IQR) PM2.5 concentrations from 93 smoking homes were 31 (10-111) μg/m(3) and 3 (2-6.5) μg/m(3) for the 17 non-smoking homes. Non-smokers living with smokers typically have average PM2.5 exposure levels more than three times higher than the WHO guidance for annual exposure to PM2.5 (10 μg/m(3)).

CONCLUSIONS

Fine particulate pollution in Scottish homes where smoking is permitted is approximately 10 times higher than in non-smoking homes. Taken over a lifetime many non-smokers living with a smoker inhale a similar mass of PM2.5 as a non-smoker living in a heavily polluted city such as Beijing. Most non-smokers living in smoking households would experience reductions of over 70% in their daily inhaled PM2.5 intake if their home became smoke-free. The reduction is likely to be greatest for the very young and for older members of the population because they typically spend more time at home.

Determination of the personal, indoor and outdoor exposure levels of inorganic gaseous pollutants in different microenvironments in an industrial city

We measured SO2, NO2 and O3 concentrations during the summer and winter in Kocaeli, Turkey. The sampling was carried out indoors and outdoors at homes, schools and offices. Personal samplers were also used to determine personal exposures to these pollutants. High NO2 and SO2 concentrations were observed in outdoor samples collected close to locations characterized by heavy urban traffic. Concentrations of O3, on the other hand, were higher in rural areas around the city due to ozone distillation. For both sampling periods, the concentrations of outdoor SO2 and O3 were higher than for indoor and personal samples; however, the NO2 concentrations were higher in indoor and personal samples, indicating that outdoor sources significantly contribute to indoor SO2 and O3 levels and that indoor NO2 concentrations are primarily modulated by sources within buildings. Seasonal variations in pollutant concentrations showed statistically significant differences. Indoor and outdoor concentrations of NO2 and SO2 measured in the winter were higher than the levels measured in the summer; O3 concentrations, on the other hand, exhibited the opposite trend. Active-to-passive concentration ratios for NO2, SO2 and O3 were 0.99, 1.08 and 1.16, respectively; the corresponding outdoor ratios were 0.95, 0.99 and 1.00.

Indicators of airborne fungal concentrations in urban homes: understanding the conditions that affect indoor fungal exposures

Indoor fungal exposure can compromise respiratory health. Low-income urban areas are of concern because of high asthma and allergy rates and housing disrepair. Understanding the conditions that affect indoor fungal exposures is important for assessing health risks and for developing mitigation strategies. We examined the types and concentrations of airborne fungi inside and outside of homes in low-income areas of Syracuse, NY as well as the effect of snow cover on fungal levels. At 103 homes, air samples for viable fungi were collected, occupants were interviewed and homes were inspected for visible mold, musty odors, water problems and other factors. Multivariable logistic regression was used to relate high fungal levels to home conditions. Predominant indoor fungi included Cladosporium, Penicillium, Aspergillus, Alternaria and hyaline unknowns. Basidiomycetes and an uncommon genus Acrodontium were also found frequently due to analysis methods developed for this project. With snow cover, outdoor total fungal levels were depressed and indoor concentrations were three times higher than outdoor on average with a maximum of 29 times higher. Visible mold was related to elevated levels of Penicillium (OR 4.11 95% CI 1.37-14.0) and bacteria (OR 3.79 95% CI 1.41-11.2). Musty, moldy odors were associated with elevated concentrations of total fungi (OR 3.48 95% CI 1.13-11.6) and basidiomycetes. Cockroaches, an indicator of moisture, were associated with elevated levels of Penicillium (OR 3.66 95% CI 1.16-13.1) and Aspergillus (OR 4.36 95% CI 1.60-13.4). Increasing relative humidity was associated with higher concentrations of Penicillium, yeasts and basidiomycetes. Visible mold, musty odors, indoor humidity and cockroaches are modifiable factors that were important determinants of indoor fungal exposures. Indoor air investigators should interpret indoor:outdoor fungal ratios cautiously when snow cover is present.

The effects of PM2.5 and its components from indoor and outdoor sources on cough and wheeze symptoms in asthmatic children

Particulate matter with aerodynamic diameter <2.5 μm (PM2.5) is associated with asthma exacerbation. In the Children's Air Pollution Asthma Study, we investigated the longitudinal association of PM2.5 and its components from indoor and outdoor sources with cough and wheeze symptoms in 36 asthmatic children. The sulfur tracer method was used to estimate infiltration factors. Mixed proportional odds models for an ordinal response were used to relate daily cough and wheeze scores to PM2.5 exposures. The odds ratio associated with being above a given symptom score for a SD increase in PM2.5 from indoor sources (PMIS) was 1.24 (95% confidence interval: 0.92-1.68) for cough and 1.63 (1.11-2.39) for wheeze. Ozone was associated with wheeze (1.82, 1.19-2.80), and cough was associated with indoor PM2.5 components from outdoor sources (denoted with subscript "OS") bromine (BrOS: 1.32, 1.05-1.67), chlorine (ClOS: 1.27, 1.02-1.59) and pyrolyzed organic carbon (OPOS: 1.49, 1.12-1.99). The highest effects were seen in the winter for cough with sulfur (SOS: 2.28, 1.01-5.16) and wheeze with organic carbon fraction 2 (OC2OS: 7.46, 1.19-46.60). Our results indicate that exposure to components originating from outdoor sources of photochemistry, diesel and fuel oil combustion is associated with symptom's exacerbation, especially in the winter. PM2.5 mass of indoor origin was more strongly associated with wheeze than with cough.

Indoor and outdoor suspended particulate matter and associated carbonaceous species at residential homes in northwestern Portugal

Particulate matter with an aerodynamic diameter equal to or less than 10 μm (PM10), organic carbon (OC) and elemental carbon (EC) concentrations were measured simultaneously in the indoor and outdoor air of 4 residences located in urban and sub-urban areas in northwestern Portugal. The residences were studied with occupants. One residence was also studied without any indoor activity, taking advantage of the fact that the occupants had moved into a new home. First, 48-h aerosol samples were collected on quartz fiber filters with low-volume samplers equipped with size selective inlets. The filters were weighed and then analyzed for OC and EC using a thermal-optical transmittance method. The average indoor and outdoor PM10 concentrations in the occupied residences were 71.9 ± 38.3 μg/m(3) and 54.0 ± 13.3 μg/m(3), respectively. Despite the higher concentration of PM10 indoors, outdoor sources were found to be a significant contributor to indoor concentrations. An estimate based on data from the residence studied under different occupancy conditions indicated that outdoor sources can account for 68% of the indoor PM10 mass concentration. Average indoor to outdoor (I/O) ratios for OC ranged from 1.7 to 5.6 in occupied residences, showing that indoor sources, such as cooking, smoking, biomass burning and movement of people, strongly influenced indoor OC concentrations. In contrast, I/O ratios for EC were close to 1, except for a smokers' residence, suggesting that indoor concentrations were mainly controlled by outdoor sources, most likely from vehicular emissions and biomass burning.

Domestic airborne pollutants and asthma and respiratory symptoms in middle age

BACKGROUND AND OBJECTIVE

The role of indoor air pollution as a risk factor for asthma and respiratory symptoms in middle age is unclear. We investigated associations between indoor air pollution sources and (i) asthma phenotypes and (ii) asthma-related respiratory symptoms in middle-aged adults.

METHODS

Subjects (n = 5729) who participated in the 2004 survey of the Tasmanian Longitudinal Health Study completed respiratory and home environment questionnaires. Associations between indoor air pollution sources, and asthma phenotypes and asthma-related respiratory symptoms were estimated.

RESULTS

Recent mould in the home was associated with current asthma (odds ratio (OR) 1.26; 95% confidence interval 1.06-1.50), wheeze (OR 1.34; 1.17-1.54) and nocturnal chest tightness (OR 1.30; 1.12-1.51). Stratified by atopy and gender, recent mould was associated with current non-atopic asthma only in males (OR 3.73; 1.29-10.80). More rooms affected by mould were associated with significant trends for current asthma, wheeze and nocturnal chest tightness. Home environmental tobacco smoke was associated with doctor-diagnosed asthma (OR 1.25; 1.02-1.53), wheeze (OR 1.69; 1.41-2.03), nocturnal chest tightness (OR 1.54; 1.26-1.88), with current asthma only in non-smokers (OR 2.09; 95%: 1.30-3.35) and with current asthma only in males (OR 1.74; 95%: 1.25-2.42). Among heating appliances, reverse cycle air conditioning was negatively associated with doctor-diagnosed asthma (OR 0.84; 0.70-1.00). Neither electric nor gas stove use was associated with either asthma phenotype or with asthma-related respiratory symptoms.

CONCLUSIONS

In middle age, reducing home exposure to mould and environmental tobacco smoke might reduce asthma and asthma-related respiratory symptoms.

Indoor aerosols: from personal exposure to risk assessment

Motivated by growing considerations of the scale, severity, and risks associated with human exposure to indoor particulate matter, this work reviewed existing literature to: (i) identify state-of-the-art experimental techniques used for personal exposure assessment; (ii) compare exposure levels reported for domestic/school settings in different countries (excluding exposure to environmental tobacco smoke and particulate matter from biomass cooking in developing countries); (iii) assess the contribution of outdoor background vs indoor sources to personal exposure; and (iv) examine scientific understanding of the risks posed by personal exposure to indoor aerosols. Limited studies assessing integrated daily residential exposure to just one particle size fraction, ultrafine particles, show that the contribution of indoor sources ranged from 19% to 76%. This indicates a strong dependence on resident activities, source events and site specificity, and highlights the importance of indoor sources for total personal exposure. Further, it was assessed that 10-30% of the total burden of disease from particulate matter exposure was due to indoor-generated particles, signifying that indoor environments are likely to be a dominant environmental factor affecting human health. However, due to challenges associated with conducting epidemiological assessments, the role of indoor-generated particles has not been fully acknowledged, and improved exposure/risk assessment methods are still needed, together with a serious focus on exposure control.

Improving pediatrician knowledge about environmental triggers of asthma

BACKGROUND

Control of environmental triggers (ETs) greatly improves asthma outcomes in children. Disseminating these findings to general pediatricians has not been well established.

METHODS

After delivering a structured and standardized presentation on ET identification and control to pediatricians, we surveyed them about knowledge and practices of ET assessment and management. We analyzed matched responses for pre/post and 3- to 6-month follow-up using McNemar's χ(2) test.

RESULTS

Matched data were available for 367 participants, and 3- to 6-month follow-up data were available for 83. There was a significant posttraining increase in intention to ask about ETs and recommend ET management. After 3 to 6 months, all responses remained significantly higher than baseline, except "likely to refer to an asthma specialist."

CONCLUSION

Pediatricians reported a significant improvement in knowledge about ETs of asthma and a willingness to incorporate exposure history questions and remediation recommendations in their routine practice.

Development of temporally refined land-use regression models predicting daily household-level air pollution in a panel study of lung function among asthmatic children

Regulatory monitoring data and land-use regression (LUR) models have been widely used for estimating individual exposure to ambient air pollution in epidemiologic studies. However, LUR models lack fine-scale temporal resolution for predicting acute exposure and regulatory monitoring provides daily concentrations, but fails to capture spatial variability within urban areas. This study coupled LUR models with continuous regulatory monitoring to predict daily ambient nitrogen dioxide (NO(2)) and particulate matter (PM(2.5)) at 50 homes in Windsor, Ontario. We compared predicted versus measured daily outdoor concentrations for 5 days in winter and 5 days in summer at each home. We also examined the implications of using modeled versus measured daily pollutant concentrations to predict daily lung function among asthmatic children living in those homes. Mixed effect analysis suggested that temporally refined LUR models explained a greater proportion of the spatial and temporal variance in daily household-level outdoor NO(2) measurements compared with daily concentrations based on regulatory monitoring. Temporally refined LUR models captured 40% (summer) and 10% (winter) more of the spatial variance compared with regulatory monitoring data. Ambient PM(2.5) showed little spatial variation; therefore, daily PM(2.5) models were similar to regulatory monitoring data in the proportion of variance explained. Furthermore, effect estimates for forced expiratory volume in 1 s (FEV(1)) and peak expiratory flow (PEF) based on modeled pollutant concentrations were consistent with effects based on household-level measurements for NO(2) and PM(2.5). These results suggest that LUR modeling can be combined with continuous regulatory monitoring data to predict daily household-level exposure to ambient air pollution. Temporally refined LUR models provided a modest improvement in estimating daily household-level NO(2) compared with regulatory monitoring data alone, suggesting that this approach could potentially improve exposure estimation for spatially heterogeneous pollutants. These findings have important implications for epidemiologic studies - in particular, for research focused on short-term exposure and health effects.

Being overweight increases susceptibility to indoor pollutants among urban children with asthma

BACKGROUND

Both being overweight and exposure to indoor pollutants, which have been associated with worse health of asthmatic patients, are common in urban minority populations. Whether being overweight is a risk factor for the effects of indoor pollutant exposure on asthma health is unknown.

OBJECTIVES

We sought to examine the effect of weight on the relationship between indoor pollutant exposure and asthma health in urban minority children.

METHODS

One hundred forty-eight children (age, 5-17 years) with persistent asthma were followed for 1 year. Asthma symptoms, health care use, lung function, pulmonary inflammation, and indoor pollutants were assessed every 3 months. Weight category was based on body mass index percentile.

RESULTS

Participants were predominantly African American (91%) and had public health insurance (85%). Four percent were underweight, 52% were normal weight, 16% were overweight, and 28% were obese. Overweight or obese participants had more symptoms associated with exposure to fine particulate matter measuring less than 2.5 μm in diameter (PM2.5) than normal-weight participants across a range of asthma symptoms. Overweight or obese participants also had more asthma symptoms associated with nitrogen dioxide (NO2) exposure than normal-weight participants, although this was not observed across all types of asthma symptoms. Weight did not affect the relationship between exposure to coarse particulate matter measuring between 2.5 and 10 μm in diameter and asthma symptoms. Relationships between indoor pollutant exposure and health care use, lung function, or pulmonary inflammation did not differ by weight.

CONCLUSION

Being overweight or obese can increase susceptibility to indoor PM2.5 and NO2 in urban children with asthma. Interventions aimed at weight loss might reduce asthma symptom responses to PM2.5 and NO2, and interventions aimed at reducing indoor pollutant levels might be particularly beneficial in overweight children.

Characterization of allergens and airborne fungi in low and middle-income homes of primary school children in Durban, South Africa

BACKGROUND

The South Durban Health Study (SDHS) is a population-based study that examined the relationship between exposure to ambient air pollutants and respiratory disease among school children with high prevalence of asthma who resided in two purposely selected communities in north and south Durban, KwaZulu-Natal, South Africa.

METHODS

From the SDHS participants, a subgroup of 135 families was selected for investigation of household characteristics potentially related to respiratory health. In these households, a walkthrough investigation was conducted, and settled dust and air samples were collected for allergen and fungal measurements using standardized techniques.

RESULTS

Asp f1 allergen was detected in all homes, and Bla g1 allergen was detected in half of the homes. House dust allergens, Der f1 and Der p1 exceeded concentrations associated with risk of sensitization and exacerbation of asthma in 3% and 13%, respectively, of the sampled homes, while Bla g1 exceeded guidance values in 13% of the homes. Although airborne fungal concentrations in sleep areas and indoors were lower than outdoor concentrations, they exceeded 1,000 CFU/m(3) in 29% of the homes. Multivariate analyses identified several home characteristics that were predictors of airborne fungal concentrations, including moisture, ventilation, floor type, and bedding type. Airborne fungal concentrations were similar indoors and outdoors, which likely reduced the significance of housing and indoor factors as determinants of indoor concentrations.

CONCLUSION

Allergen concentrations were highly variable in homes, and a portion of the variability can be attributed to easily recognized conditions.

Environmental monitoring of secondhand smoke exposure

The complex composition of secondhand smoke (SHS) provides a range of constituents that can be measured in environmental samples (air, dust and on surfaces) and therefore used to assess non-smokers' exposure to tobacco smoke. Monitoring SHS exposure (SHSe) in indoor environments provides useful information on the extent and consequences of SHSe, implementing and evaluating tobacco control programmes and behavioural interventions, and estimating overall burden of disease caused by SHSe. The most widely used markers have been vapour-phase nicotine and respirable particulate matter (PM). Numerous other environmental analytes of SHS have been measured in the air including carbon monoxide, 3-ethenylpyridine, polycyclic aromatic hydrocarbons, tobacco-specific nitrosamines, nitrogen oxides, aldehydes and volatile organic compounds, as well as nicotine in dust and on surfaces. The measurement of nicotine in the air has the advantage of reflecting the presence of tobacco smoke. While PM measurements are not as specific, they can be taken continuously, allowing for assessment of exposure and its variation over time. In general, when nicotine and PM are measured in the same setting using a common sampling period, an increase in nicotine concentration of 1 μg/m³ corresponds to an average increase of 10 μg/m³ of PM. This topic assessment presents a comprehensive summary of SHSe monitoring approaches using environmental markers and discusses the strengths and weaknesses of these methods and approaches.

Particulate matter concentrations in residences: an intervention study evaluating stand-alone filters and air conditioners

This study, a randomized controlled trial, evaluated the effectiveness of free-standing air filters and window air conditioners (ACs) in 126 low-income households of children with asthma. Households were randomized into a control group, a group receiving a free-standing HEPA filter placed in the child's sleeping area, and a group receiving the filter and a window-mounted AC. Indoor air quality (IAQ) was monitored for week-long periods over three to four seasons. High concentrations of particulate matter (PM) and carbon dioxide were frequently seen. When IAQ was monitored, filters reduced PM levels in the child's bedroom by an average of 50%. Filter use varied greatly among households and declined over time, for example, during weeks when pollutants were monitored, filter use was initially high, averaging 84±27%, but dropped to 63±33% in subsequent seasons. In months when households were not visited, use averaged only 34±30%. Filter effectiveness did not vary in homes with central or room ACs. The study shows that measurements over multiple seasons are needed to characterize air quality and filter performance. The effectiveness of interventions using free-standing air filters depends on occupant behavior, and strategies to ensure filter use should be an integral part of interventions.

PRACTICAL IMPLICATIONS

Environmental tobacco smoke (ETS) increased particulate matter (PM) levels by about 14 μg/m3 and was often detected using ETS-specific tracers despite restrictions on smoking in the house as reported on questionnaires administered to caregivers. PM concentrations depended on season, filter usage, relative humidity, air exchange ratios, number of children, outdoor PM levels, sweeping/dusting, and presence of a central air conditioner (AC). Free-standing air filters can be an effective intervention that provides substantial reductions in PM concentrations if the filters are used. However, filter use was variable across the study population and declined over the study duration, and thus strategies are needed to encourage and maintain use of filters. The variability in filter use suggests that exposure misclassification is a potential problem in intervention studies using filters. The installation of a room AC in the bedroom, intended to limit air exchange ratios, along with an air filter, did not lower PM levels more than the filter alone.

Toxic elements in tobacco and in cigarette smoke: inflammation and sensitization

Biochemically and pathologically, there is strong evidence for both atopic and nonatopic airway sensitization, hyperresponsiveness, and inflammation as a consequence of exposure to tobacco mainstream or sidestream smoke particulate. There is growing evidence for the relation between exposure to mainstream and sidestream smoke and diseases resulting from reactive oxidant challenge and inflammation directly as a consequence of the combined activity of neutrophils, macrophages, dendritic cells, eosinophils, basophils, as a humoral immunological consequence of sensitization, and that the metal components of the particulate play a role in adjuvant effects. As an end consequence, carcinogenicity is a known outcome of chronic inflammation. Smokeless tobacco has been evaluated by the IARC as a group 1 carcinogen. Of the many harmful constituents in smokeless tobacco, oral tissue metallothionein gradients suggest that metals contribute to the toxicity from smokeless tobacco use and possibly sensitization. This work reviews and examines work on probable contributions of toxic metals from tobacco and smoke to pathology observed as a consequence of smoking and the use of smokeless tobacco.

Levels of household particulate matter and environmental tobacco smoke exposure in the first year of life for a cohort at risk for asthma in urban Syracuse, NY

The Syracuse, NY, AUDIT (Assessment of Urban Dwellings for Indoor Toxics) study was designed to quantify asthma agent levels in the inner-city homes of a birth cohort whose mothers had a diagnosis of asthma. Risk of exposure to particulate matter (PM), particle number and tobacco smoke was assessed in 103 infants' homes. Repeat measurements were made in 44% of the homes. Infants also were examined on a quarterly basis during the first year of life to monitor their respiratory health and urine cotinine levels. Overall geometric mean (GM) values for PM(2.5) of 21.2 μg/m(3) and for PM(10) of 31.8 μg/m(3) were recorded in homes at visit 1. GM values for PM(2.5) and PM(10) in smoking homes were higher at 26.3 and 37.7 μg/m(3), while values in non-smoking homes were 12.7 and 21.2 μg/m(3) respectively. Fifty-four percent of mothers (55/103) smoked at some point in pregnancy (39% smoked throughout pregnancy). Environmental tobacco smoke (ETS) exposure occurred in 68% of homes during the infants' first year. Significant to this study was the size- and time-resolved monitoring of PM at 140 home visits and the classification of PM count data. PM number counts ranged from continuously low levels (little indoor activity) to continuously high counts (constant indoor activity), and recorded apparent instances of prolonged repeated cigarette smoking. Wheezing in the first year of life was recorded for 38% of the infants (39/103). Adjusted logistic regression modeling demonstrated that elevated levels of indoor PM(2.5) (≥ 15 μg/m(3)) were a significant risk factor for infant wheezing after controlling for infant gender, mothers' age and education level, season of home visit and presence of carpeting (OR 4.21; 95% CI 1.36-13.03; p=0.013). An elevated level of the nicotine metabolite cotinine in infant urine also was associated with infant wheezing after adjusting for infant gender, mothers' age and education level (OR 5.10; 95% CI 0.96-27.24; p=0.057). ETS exposure was pervasive in the AUDIT cohort and a risk for developing infants in this urban population.

Particle Concentrations and Effectiveness of Free-Standing Air Filters in Bedrooms of Children with Asthma in Detroit, Michigan

Asthma can be exacerbated by environmental factors including airborne particulate matter (PM) and environmental tobacco smoke (ETS). We report on a study designed to characterize PM levels and the effectiveness of filters on pollutant exposures of children with asthma. 126 households with an asthmatic child in Detroit, Michigan, were recruited and randomized into control or treatment groups. Both groups received asthma education; the latter also received a free-standing high efficiency air filter placed in the child's bedroom. Information regarding the home, emission sources, and occupant activities was obtained using surveys administered to the child's caregiver and a household inspection. Over a one-week period, we measured PM, carbon dioxide (CO(2)), environmental tobacco smoke (ETS) tracers, and air exchange rates (AERs). Filters were installed at midweek. Before filter installation, PM concentrations averaged 28 µg m(-3), number concentrations averaged 70,777 and 1,471 L(-1) in 0.3-1.0 and 1-5 µm size ranges, respectively, and the median CO(2) concentration was 1,018 ppm. ETS tracers were detected in 23 of 38 homes where smoking was unrestricted and occupants included smokers and, when detected, PM concentrations were elevated by an average of 15 µg m(-3). Filter use reduced PM concentrations by an average of 69 to 80%. Simulation models representing location conditions show that filter air flow, room volume and AERs are the key parameters affecting PM removal, however, filters can achieve substantial removal in even "worst" case applications. While PM levels in homes with asthmatic children can be high, levels can be dramatically reduced using filters.

Predicting future asthma morbidity in preschool inner-city children

BACKGROUND AND AIMS

Children living in the inner city are particularly vulnerable to asthma. While we know much about factors that affect near-term outcomes in inner-city children, there is little evidence to guide clinicians on what to expect in the coming years, especially in preschool children. The purpose of our study was to determine which clinical and environmental factors are predictive of poor long-term asthma control in preschool inner-city children.

MATERIALS AND METHODS

Baseline characteristics determined to be potential predictors of asthma severity were examined: demographics, asthma symptoms, medication use, healthcare utilization, early life medical history, family history, allergen exposure and allergic disease, and pollutant exposure. Bivariate and multivariate analyses were performed using logistic regression to examine the association of predictors of asthma severity with healthcare utilization at 2 years.

RESULTS

Of the 150 children at baseline, the follow-up rate was 83% at 2 years; therefore, 124 children were included in final analyses. At baseline, the mean age was 4.4 years and participants were predominantly African-American (90%). Most of the children were atopic and 32.5% reported using inhaled corticosteroids. Nighttime awakening from asthma and a history of pneumonia were predictive of future poor control.

CONCLUSION

Preschool children with nighttime awakening from asthma and a history of pneumonia may deserve closer monitoring to prevent future asthma morbidity.

Effectiveness of home-based, multi-trigger, multicomponent interventions with an environmental focus for reducing asthma morbidity: a community guide systematic review

CONTEXT

Asthma exacerbations are commonly triggered by exposure to allergens and irritants within the home. The purpose of this review was to evaluate evidence that interventions that target reducing these triggers through home visits may be beneficial in improving asthma outcomes. The interventions involve home visits by trained personnel to conduct two or more components that address asthma triggers in the home. Intervention components focus on reducing exposures to a range of asthma triggers (allergens and irritants) through environmental assessment, education, and remediation.

EVIDENCE ACQUISITION

Using methods previously developed for the Guide to Community Preventive Services, a systematic review was conducted to evaluate the evidence on effectiveness of home-based, multi-trigger, multicomponent interventions with an environmental focus to improve asthma-related morbidity outcomes. The literature search identified over 10,800 citations. Of these, 23 studies met intervention and quality criteria for inclusion in the final analysis.

EVIDENCE SYNTHESIS

In the 20 studies targeting children and adolescents, the number of days with asthma symptoms (symptom-days) was reduced by 0.8 days per 2 weeks, which is equivalent to 21.0 symptom-days per year (range of values: reduction of 0.6 to 2.3 days per year); school days missed were reduced by 12.3 days per year (range of values: reduction of 3.4 to 31.2 days per year); and the number of asthma acute care visits were reduced by 0.57 visits per year (interquartile interval: reduction of 0.33 to 1.71 visits per year). Only three studies reported outcomes among adults with asthma, finding inconsistent results.

CONCLUSIONS

Home-based, multi-trigger, multicomponent interventions with an environmental focus are effective in improving overall quality of life and productivity in children and adolescents with asthma. The effectiveness of these interventions in adults is inconclusive due to the small number of studies and inconsistent results. Additional studies are needed to (1) evaluate the effectiveness of these interventions in adults and (2) determine the individual contributions of the various intervention components.

The indoor environment and its effects on childhood asthma

PURPOSE OF REVIEW

Indoor pollutants and allergens cause asthma symptoms and exacerbations and influence the risk of developing asthma. We review recent studies regarding the effects of the indoor environment on childhood asthma.

RECENT FINDINGS

Exposure to some indoor allergens and second hand smoke are causally related to the development of asthma in children. Many recent studies have demonstrated an association between exposure to indoor pollutants and allergens and airways inflammation, asthma symptoms, and increased healthcare utilization among individuals with established asthma. Genetic polymorphisms conferring susceptibility to some indoor exposures have also been identified, and recent findings support the notion that environmental exposures may influence gene expression through epigenetic modification. Recent studies also support the efficacy of multifaceted environmental interventions in childhood asthma.

SUMMARY

Studies have provided significant evidence of the association between many indoor pollutants and allergens and asthma morbidity, and have also demonstrated the efficacy of multifaceted indoor environmental interventions in childhood asthma. There is also a growing body of evidence suggesting that some indoor pollutants and allergens may increase the risk of developing asthma. Future studies should examine mechanisms whereby environmental exposures may influence asthma pathogenesis and expand the current knowledge of susceptibility factors for indoor exposures.

Nurse case management and housing interventions reduce allergen exposures: the Milwaukee randomized controlled trial

OBJECTIVE

We examined the impact of a combination of home environmental interventions and nurse case management services on total settled dust loadings and on allergen concentrations in the homes of asthmatic children. METHODS Using a randomized longitudinal controlled trial study design, we randomly assigned homes of asthmatic children in Milwaukee to either a control (n = 64) or an intervention (n = 57) group. Control group homes received a visual assessment, education, bed/pillow dust mite encasings, and treatment of lead-based paint hazards. The intervention group received these same services plus nurse case management that included tailored, individual asthma action plans, provision of minor home repairs, home cleaning using special vacuuming and wet washing, and integrated pest management. Dust vacuum samples were collected from measured surface areas of floors in the TV room, kitchen, and child's bedroom at baseline and at three-, six-, and 12-month follow-up visits. Dust loading (mass per surface area) is a means of measuring total dust and the total amount of allergen present.

RESULTS

For the intervention group, geometric mean dust loadings declined significantly from baseline (39 milligrams per square foot [mg/ft2]) to postintervention (11 mg/ft2) (p < 0.001). Baseline dust loading, treatment group, visit, and season were significant predictors of follow-up dust loadings. Mean post-intervention dust loadings were 72% higher in the control group. The total amount of allergen in settled house dust declined significantly following the intervention because total dust loading declined; the concentration of allergens in settled dust did not change significantly.

CONCLUSION

The combination of nurse case management and home environmental interventions promotes collaboration between health and housing professionals and is effective in reducing exposures to allergens in settled dust.

Indoor air pollution and asthma in children

The purpose of this article is to review indoor air pollution factors that can modify asthma severity, particularly in inner-city environments. While there is a large literature linking ambient air pollution and asthma morbidity, less is known about the impact of indoor air pollution on asthma. Concentrating on the indoor environments is particularly important for children, since they can spend as much as 90% of their time indoors. This review focuses on studies conducted by the Johns Hopkins Center for Childhood Asthma in the Urban Environment as well as other relevant epidemiologic studies. Analysis of exposure outcome relationships in the published literature demonstrates the importance of evaluating indoor home environmental air pollution sources as risk factors for asthma morbidity. Important indoor air pollution determinants of asthma morbidity in urban environments include particulate matter (particularly the coarse fraction), nitrogen dioxide, and airborne mouse allergen exposure. Avoidance of harmful environmental exposures is a key component of national and international guideline recommendations for management of asthma. This literature suggests that modifying the indoor environment to reduce particulate matter, NO(2), and mouse allergen may be an important asthma management strategy. More research documenting effectiveness of interventions to reduce those exposures and improve asthma outcomes is needed.

The state of indoor air quality in Pakistan--a review

BACKGROUND AND PURPOSE

In Pakistan, almost 70% of the population lives in rural areas. Ninety-four percent of households in rural areas and 58% in urban areas depend on biomass fuels (wood, dung, and agricultural waste). These solid fuels have poor combustion efficiency. Due to incomplete combustion of the biomass fuels, the resulting smoke contains a range of health-deteriorating substances that, at varying concentrations, can pose a serious threat to human health. Indoor air pollution accounts for 28,000 deaths a year and 40 million cases of acute respiratory illness. It places a significant economic burden on Pakistan with an annual cost of 1% of GDP. Despite the mounting evidence of an association between indoor air pollution and ill health, policy makers have paid little attention to it. This review analyzes the existing information on levels of indoor air pollution in Pakistan and suggests suitable intervention methods.

METHODS

This review is focused on studies of indoor air pollution, due to biomass fuels, in Pakistan published in both scientific journals and by the Government and international organizations. In addition, the importance of environmental tobacco smoke as an indoor pollutant is highlighted.

RESULTS

Unlike many other developing countries, there are no long-term studies on the levels of indoor air pollution. The limited studies that have been undertaken indicate that indoor air pollution should be a public health concern. High levels of particulate matter and carbon monoxide have been reported, and generally, women and children are subject to the maximum exposure. There have been a few interventions, with improved stoves, in some areas since 1990. However, the effectiveness of these interventions has not been fully evaluated.

CONCLUSION

Indoor air pollution has a significant impact on the health of the population in Pakistan. The use of biomass fuel as an energy source is the biggest contributor to poor indoor air quality followed by smoking. In order to arrest the increasing levels of indoor pollution, there is a dire need to recognize it as a major health hazard and formulate a national policy to combat it. An integrated effort, with involvement of all stakeholders, could yield promising results. A countrywide public awareness campaign, on the association of indoor air pollution with ill health, followed by practical intervention would be an appropriate approach. Due to the current socioeconomic conditions in the country, development and adoption of improved cooking stoves for the population at large would be the most suitable choice. However, the potential of biogas as a fuel should be explored further, and modern fuels (natural gas and LPG) need to be accessible and economical. Smoking in closed public spaces should be banned, and knowledge of the effect of smoking on indoor air quality needs to be quantified.

Environmental and occupational allergies

Airborne allergens are the major cause of allergic rhinitis and asthma. Daily exposure comes from indoor sources, chiefly at home but occasionally at schools or offices. Seasonal exposure to outdoor allergens, pollens, and molds is another important source. Exposure to unusual substances at work causes occupational asthma, accounting for about 5% of asthma in adults. Indoor and outdoor air pollutants trigger airway inflammation and increase the severity of asthma. Diesel exhaust particles increase the production of IgE antibodies. Identification and reduction of exposure to allergens is a very important part of the management of respiratory allergic diseases. The first section of this chapter discusses domestic allergens, arthropods (mites and cockroaches), molds, and mammals (pets and mice). Indoor humidity and water damage are important factors in the production of mite and mold allergens, and discarded human food items are important sources of proliferation of cockroaches and mice. Means of identifying and reducing exposure are presented. The second section discusses outdoor allergens: pollens and molds. The particular plants or molds and the amount of exposure to these allergens is determined by the local climate, and local pollen and mold counts are available to determine the time and amount of exposure. Climate change is already having an important effect on the distribution and amount of outdoor allergens. The third section discusses indoor and outdoor air pollution and methods that individuals can take to reduce indoor pollution in addition to eliminating cigarette smoking. The fourth section discusses the diagnosis and management of occupational asthma.