Personal NO2 Research Articles

Measured and modeled personal and environmental NO2 exposure

BackgroundMeasured or modeled levels of outdoor air pollution are being used as proxies for individual exposure in a growing number of epidemiological studies. We studied the accuracy of such approaches, in comparison with measured individual levels, and also combined modeled levels for each subject’s workplace with the levels at their residence to investigate the influence of living and working in different places on individual exposure levels.MethodsA GIS-based dispersion model and an emissions database were used to model concentrations of NO2 at the subject’s residence. Modeled levels were then compared with measured levels of NO2. Personal exposure was also modeled based on levels of NO2 at the subject’s residence in combination with levels of NO2 at their workplace during working hours.ResultsThere was a good agreement between measured façade levels and modeled residential NO2 levels (rs = 0.8, p > 0.001); however, the agreement between measured and modeled outdoor levels and measured personal exposure was poor with overestimations at low levels and underestimation at high levels (rs = 0.5, p > 0.001 and rs = 0.4, p > 0.001) even when compensating for workplace location (rs = 0.4, p > 0.001).ConclusionModeling residential levels of NO2 proved to be a useful method of estimating façade concentrations. However, the agreement between outdoor levels (both modeled and measured) and personal exposure was, although significant, rather poor even when compensating for workplace location. These results indicate that personal exposure cannot be fully approximated by outdoor levels and that differences in personal activity patterns or household characteristics should be carefully considered when conducting exposure studies. This is an important finding that may help to correct substantial bias in epidemiological studies.

Associations between personal exposures and ambient concentrations of nitrogen dioxide: A quantitative research synthesis

Although positive associations between ambient NO2 concentrations and personal exposures have generally been found by exposure studies, the strength of the associations varied among studies. Differences in results could be related to differences in study design and in exposure factors. However, the effects of study design, exposure factors, and sampling and measurement errors on the strength of the personal-ambient associations have not been evaluated quantitatively in a systematic manner. A quantitative research synthesis was conducted to examine these issues based on peer-reviewed publications in the past 30 years. Factors affecting the strength of the personal-ambient associations across the studies were also examined with meta-regression. Ambient NO2 was found to be significantly associated with personal NO2 exposures, with estimates of 0.42, 0.16, and 0.72 for overall pooled, longitudinal and daily average correlation coefficients based on random-effects meta-analysis. This conclusion was robust after correction for publication bias with correlation coefficients of 0.37, 0.16 and 0.45. We found that season and some population characteristics, such as pre-existing disease, were significant factors affecting the strength of the personal-ambient associations. More meaningful and rigorous comparisons would be possible if greater detail were published on the study design (e.g. local and indoor sources, housing characteristics, etc.) and data quality (e.g., detection limits and percent of data above detection limits).

Performance of a microenviromental model for estimating personal NO2 exposure in children

Abstract A common problem in epidemiological studies on air pollution is exposure misclassification, because investigators often assume exposure is equivalent to outdoor concentrations at participants’ homes or at the nearest urban monitor. The aims of this study were: (1) to develop a new microenvironmental exposure model (MEEM), combining time-activity data with modelled outdoor and indoor NO 2 concentrations; (2) to evaluate MEEM against data collected with Ogawa™ personal samplers (OPS); (3) to compare its performance against datasets typically used in epidemiological studies. Schoolchildren wore a personal NO 2 sampler, kept a time-activity diary and completed a questionnaire. This information was used by MEEM to estimate individuals’ exposures. These were then compared against concentrations measured by OPS, modelled outdoor concentrations at the children’s home (HOME) and concentrations measured at the nearest urban monitoring station (NUM). The mean exposure predicted by MEEM (mean = 19.6 μg m − ³) was slightly lower than the mean exposure measured by OPS (mean = 20.4 μg m − ³). The normalised mean bias factor (0.01) and normalised mean absolute error factor (0.25) suggested good agreement. In contrast, the HOME (mean = 31.2 μg m − ³) and NUM (mean = 28.6 μg m − ³) methods overpredicted exposure and showed systematic errors. The results indicate that personal exposure can be modelled by MEEM with an acceptable level of agreement, while methods such as HOME and NUM show a poorer performance.

Impact of personal and ambient-level exposures to nitrogen dioxide and particulate matter on cardiovascular function

This work explored the association between nitrogen dioxide (NO2) and PM2.5 components with changes in cardiovascular function in an adult non-smoking cohort. The cohort consisted of 65 volunteers participating in the US EPA's Detroit Exposure and Aerosol Research Study (DEARS) and a University of Michigan cardiovascular sub-study. Systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), brachial artery diameter (BAD), brachial artery flow-mediated dilatation (FMD) and nitroglycerin-mediated arterial dilatation (NMD) were collected by in-home examinations. A maximum of 336 daily environmental and health effect observations were obtained. Daily potassium air concentrations were associated with significant decreases in DBP (−0.0447 mmHg/ng/m3 ± 0.0132, p = 0.0016, lag day 0) among participants compliant with the personal monitoring protocol. Personal NO2 exposures resulted in significant changes in BAD (e.g., 0.0041 mm/ppb ± 0.0019, p = 0.0353, lag day 1) and FMD (0.0612 ± 0.0235, p = 0.0103, lag day 0) among other findings.

The influence of human and environmental exposure factors on personal NO2 exposures

The US Environmental Protection Agency's (US EPA) Detroit Exposure and Aerosol Research Study (DEARS) deployed a total of over 2000 nitrogen dioxide, NO(2,) passive monitors during 3 years of field data collections. These 24-h based personal, residential outdoor and community-based measurements allowed for the investigation of NO(2) spatial, temporal, human and environmental factors. The relationships between personal exposures to NO(2) and the factors that influence the relationship with community-based measurements were of interest. Survey data from 136 participants were integrated with exposure findings to allow for mixed model effect analyses. Ultimately, 50 individual factors were selected for examination. NO(2) analyses revealed that season, exposure to environmental tobacco smoke and residential gas appliances were strong influencing factors. Only modest associations between community-based measures of nitrogen dioxide and personal exposures impacted by various exposure factors for heating (r=0.44) or non-heating seasons (r=0.34) were observed, indicating that use of ambient-based monitoring as a surrogate of personal exposure might result in sizeable exposure misclassification.

Indoor, Outdoor, and Personal Exposure to Nitrogen Dioxide Comparing Industrial Complex Area With Country Area

O-31A6-2 Background/Aims: Indoor air quality can be affected by indoor sources, ventilation, decay, and outdoor levels. Various indoor and outdoor combustion sources produce nitrogen dioxide (NO2), which is a by-product of high temperature fossil fuel combustion. Especially, the presence of gas ranges and smoking have been identified as major factors contributing to indoor NO2 exposures. In this study, we compared an industrial complex area with a country area by assessing the personal exposure to NO2 with measurements of indoor and outdoor NO2 levels in residences and by house characteristics and questionnaire. Methods: Residential indoor and outdoor NO2 concentrations and personal NO2 exposures were measured for 90 participants in industrial complex area and 30 participants in country area, respectively. Questionnaires related personal life-style and house characteristic were administrated. All measurements were used passive air sampler. Results: Personal exposure concentrations were significantly correlated with indoor NO2 concentrations of residences in both the industrial complex area and the country area with correlation coefficients of 0.561 and 0.664, respectively, compared to outdoors. Multiple regression analysis indicated that indoor NO2 levels in residences were only affected by outdoor levels (P = 0.000) despite higher indoor sources such as smoking. Conclusion: This study is suggested that outdoor air quality as well as indoor air quality should be considered in the reduction of the personal exposure to air pollutants.

Exposure Error Masks the Relationship Between Traffic-Related Air Pollution and Heart Rate Variability

We examined whether more precise exposure measures would better detect associations between traffic-related pollution, elemental carbon (EC), nitrogen dioxide (NO2), and heart rate variability (HRV). Repeated 24-hour personal and ambient PM2.5, EC, and NO2 were measured for 30 people living in Atlanta, GA. The association between HRV and either ambient concentrations or personal exposures was examined using linear mixed effects models. Ambient PM2.5, EC, NO2, and personal PM2.5 were not associated with HRV. Personal EC and NO2 measured 24 hours before HRV were associated with decreased RMSSD, PNN50, and HF and with increased LF/HF. RMSSD decreased by 10.97% (95% confidence interval: -18.00 to -3.34) for an inter-quartile range change in personal EC (0.81 microg/m3). Results indicate decreased vagal tone in response to traffic pollutants, which can best be detected with precise personal exposure measures.

Predicting Personal Nitrogen Dioxide Exposure in an Elderly Population: Integrating Residential Indoor and Outdoor Measurements, Fixed-Site Ambient Pollution Concentrations, Modeled Pollutant Levels, and Time–Activity Patterns

Predicting chronic exposure to air pollution at the intra-urban scale has been recognized as a priority area of research for environmental epidemiology. Exposure assessment models attempt to predict and proxy for individuals' personal exposure to ambient air pollution, and there are no studies to date that explicitly attempt to compare and cross-validate personal exposure concentrations with pollutants modeled at the intra-urban level using methods such as interpolated surfaces and land-use regression (LUR) models. This study aimed to identify how well personal exposure to NO2 (nitrogen dioxide) can be predicted from ambient exposure measurements and intra-urban exposure estimates using LUR and what other factors contribute to predicting variations in personal exposure beyond measured pollutant levels within home. Personal, indoor and outdoor NO2 were measured in a population of older adults (>65 yr old) living in Hamilton, Canada. Our results show that personal NO2 was most strongly associated with contemporaneously collected indoor and outdoor concentrations of NO2. Predicted NO2 exposures from intra-urban LUR models were not associated with personal NO2, whereas interpolated surfaces of particulates and ozone were modestly associated. Combinations of variables that best predicted personal NO2 variability were derived from time–activity diaries, interpolated surfaces of ambient particulate pollutants, and a citywide temporally matched average of NO2. The nonsignificant associations between personal NO2 and the modeled ambient NO2 concentrations suggest that observed associations between NO2 generated by LUR models and health effects are probably not produced by NO2, but by other pollutants that follow a similar spatial pattern.

Prenatal Personal VOCs and Outdoor NO2 Exposure Effects on Birth Outcome and Infant’s Atopic Dermatitis at 6 Month: MOther and Children’s Environmental Health (MOCEH)

Prenatal Personal VOCs and Outdoor NO2 Exposure Effects on Birth Outcome and Infant’s Atopic Dermatitis at 6 Month: MOther and Children’s Environmental Health (MOCEH)

Assessment of Personal NO2 Exposure Using GIS in Pregnant Women From Inma-valencia, Spain

Assessment of Personal NO2 Exposure Using GIS in Pregnant Women From Inma-valencia, Spain

Health risk assessment of indoor air pollution in Finnish ice arenas

Poor indoor air quality and epidemic carbon monoxide (CO) and nitrogen dioxide (NO2) poisonings due to exhaust emissions from ice resurfacers have been continuously reported from enclosed ice arenas for over 30 years. The health risks in users of Finnish ice arenas were analysed in three ways: (1) evaluation of four cases of epidemic CO poisonings, (2) modelling the association between NO2 exposure and respiratory symptoms among junior ice hockey players, and (3) estimation of the number of arena users at risk of breathing poor quality air due to non-compliance of ice arenas with recommended abatement measures. The common causes for the CO poisonings involving over 300 subjects were large emissions from propane-fuelled ice resurfacer, small arena volume, negligible ventilation, and very recent opening of the arena. Rhinitis (prevalence 18.3%) and cough (13.7%) during or after training or game were significantly associated with the estimated personal NO2 exposure of young hockey players (n=793) to average concentrations ranging from 21 to 1176 μg/m3 in their home arena. During a 6-year follow-up of an intensive information campaign the portion of electric resurfacers increased from 9% to 27%, and that of emission control technology on propane-fuelled resurfacers increased from 13% to 84%. The portion of inadequately ventilated arenas decreased from 34% to 25%. However, 48% of the investigated Finnish ice arenas (n=125) did not fully comply with the non-regulatory recommendations. Consequently, 20000 daily users of ice arenas were estimated to remain in 2001 at risk of breathing poor quality air. Modern small and inadequately ventilated ice arenas pose their users (mostly children and young adults) at risk of breathing poor quality air and suffering from acute adverse health effects. Governmental regulations are needed worldwide to ensure safe sports in enclosed ice arenas.

Effects of Personal Exposure to Nitrogen Dioxide on Peak Expiratory Flow in Asthmatic Patients

Nitrogen dioxide (NO2) has been inconsistently associated with gradual decreases in lung function. Here, we studied the effects of NO2 exposure in asthmatics by examining the association between changes in lung function and concentrations of NO2 which were personally measured. Peak expiratory flow (PEF) and daily personal exposures to NO2 were recorded on 28 patients with asthma (confirmed by methacholine provocation test) over 4 weeks. We used generalized estimating equations to assess the relationship between personal NO2 exposure and PEF, adjusting for potential confounders such as age, gender, outdoor particulate matter, temperature, humidity, and exposure to environmental tobacco smoke. The personal NO2 exposures were higher than the corresponding ambient levels. The mean personal: ambient ratio for NO2 was 1.48. The personal NO2 exposures were not associated with the morning PEF, evening PEF, or the diurnal PEF variability. However, environmental tobacco smoke was negatively associated with both the morning and evening PEF. Among the asthmatic adults who participated in this study, we found no apparent impact of personal NO2 exposures on the peak expiratory flow.

Personal and Ambient Air Pollution is Associated with Increased Exhaled Nitric Oxide in Children with Asthma

BackgroundResearch has shown associations between pediatric asthma outcomes and airborne particulate matter (PM). The importance of particle components remains to be determined.MethodsWe followed a panel of 45 schoolchildren with persistent asthma living in Southern California. Subjects were monitored over 10 days with offline fractional exhaled nitric oxide (FeNO), a biomarker of airway inflammation. Personal active sampler exposures included continuous particulate matter < 2.5 μm in aerodynamic diameter (PM2.5), 24-hr PM2.5 elemental and organic carbon (EC, OC), and 24-hr nitrogen dioxide. Ambient exposures included PM2.5, PM2.5 EC and OC, and NO2. Data were analyzed with mixed models controlling for personal temperature, humidity and 10-day period.ResultsThe strongest positive associations were between FeNO and 2-day average pollutant concentrations. Per interquartile range pollutant increase, these were: for 24 μg/m3 personal PM2.5, 1.1 ppb FeNO [95% confidence interval (CI), 0.1–1.9]; for 0.6 μg/m3 personal EC, 0.7 ppb FeNO (95% CI, 0.3–1.1); for 17 ppb personal NO2, 1.6 ppb FeNO (95% CI, 0.4–2.8). Larger associations were found for ambient EC and smaller associations for ambient NO2. Ambient PM2.5 and personal and ambient OC were significant only in subjects taking inhaled corticosteroids (ICS) alone. Subjects taking both ICS and antileukotrienes showed no significant associations. Distributed lag models showed personal PM2.5 in the preceding 5 hr was associated with FeNO. In two-pollutant models, the most robust associations were for personal and ambient EC and NO2, and for personal but not ambient PM2.5.ConclusionPM associations with airway inflammation in asthmatics may be missed using ambient particle mass, which may not sufficiently represent causal pollutant components from fossil fuel combustion.

Environmental NO2 Raises Severity of Virus-induced Asthma

Epidemiology| September 01 2003 Environmental NO2 Raises Severity of Virus-induced Asthma AAP Grand Rounds (2003) 10 (3): 29–30. https://doi.org/10.1542/gr.10-3-29 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Environmental NO2 Raises Severity of Virus-induced Asthma. AAP Grand Rounds September 2003; 10 (3): 29–30. https://doi.org/10.1542/gr.10-3-29 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search nav search search input Search input auto suggest search filter All PublicationsAll JournalsAAP Grand RoundsPediatricsHospital PediatricsPediatrics In ReviewNeoReviewsAAP NewsAll AAP Sites Search Advanced Search Topics: asthma Source: Chauhan AJ, Inskip HM, Linaker CH, et al. Personal exposure to nitrogen dioxide (NO2) and the severity of virus-induced asthma in children. Lancet. 2003;361:1939–1944. Investigators from the University of Southampton and Imperial College, London, England assessed whether there is a relationship between nitrogen dioxide (NO2) exposure and the severity of childhood asthma exacerbations due to documented viral infections. In a cohort of 114 children aged 8–11 years, daily upper and lower respiratory tract symptoms, peak expiratory flow, and weekly personal NO2 exposure measurements were followed for up to 13 months. Children of smokers were excluded. Nasal aspirates during reported upper respiratory tract illness were tested for common respiratory viruses, Chlamydia pneumoniae, and Mycoplasma pneumoniae. Exposure to NO2 Exposure to in the week before or after upper respiratory tract infection was divided into tertiles and analyzed in... You do not currently have access to this content.

EFFECT OF PERSONAL EXPOSURE TO NITROGEN DIOXIDE ON PULMONARY FUNCTION

Introduction Exposure to air pollution has been reported to be associated with decrease in pulmonary function. The aims of the present study were to investigate whether there is a relationship between exposure to nitrogen dioxide (NO2) in ambient air and cardiovascular risk biomarkers or pulmonary function. Methods We measured personal NO2 concentrations for three hundred healthy university students (277 males and 21 females) using passive sampling tubes. Questionnaire interview, blood sampling, and spirometry were performed at the time of returning the samplers after 1 day. Results Personal NO2 concentrations were significantly different depending on distance of home to the main road (33.43 ppb < 500m vs. 27.42 ppb > 500m, P = 0.023). Students commuting by bus had higher levels of NO2 than those using other transportations (34.39 ppb vs. 32.35 ppb, P = 0.042). Evaluation of the association between NO2 exposure level and cardiovascular risk biomarkers did not show significant relationships. However, significant decreases in the ratio of the forced expiratory volume in one second and the forced vital capacity (FEV1/FVC), and midexpiratory flow between 25 and 75% of the forced vital capacity (MEF25–75%) were associated with increase of NO2 exposure level (P < 0.05). Conclusions This study indicates that personal exposure concentrations to NO2 are significantly influenced by the distance to a main road and the transportation vehicles. The NO2 exposure is associated with decrease of pulmonary function, but not with cardiovascular risk biomarkers. These effects support the association between ambient air monitoring level of NO2 and pulmonary functional disturbance.

Personal exposure to nitrogen dioxide (NO 2) and the severity of virus-induced asthma in children

SummaryBackgroundA link between exposure to the air pollutant nitrogen dioxide (NO2) and respiratory disease has been suggested. Viral infections are the major cause of asthma exacerbations. We aimed to assess whether there is a relation between NO2 exposure and the severity of asthma exacerbations caused by proven respiratory viral infections in children.MethodsA cohort of 114 asthmatic children aged between 8 and 11 years recorded daily upper and lower respiratory-tract symptoms, peak expiratory flow (PEF), and measured personal NO2 exposures every week for up to 13 months. We took nasal aspirates during reported episodes of upper respiratory-tract illness and tested for infection by common respiratory viruses and atypical bacteria with RT-PCR assays. We used generalised estimating equations to assess the relation between low (<7·5 μg/m3), medium (7·5–14 μg/m3), and high (>14 μg/m3) tertiles of NO2 exposure in the week before or after upper respiratory-tract infection and the severity of asthma exacerbation in the week after the start of an infection.FindingsOne or more viruses were detected in 78% of reported infection episodes, and the medians of NO2 exposure were 5 (IQR 3·6–6·3), 10 (8·7–12·0), and 21 μg/m3 (16·8–42·9) for low, medium, and high tertiles, respectively. There were significant increases in the severity of lower respiratory-tract symptom scores across the three tertiles (0·6 for all viruses [p=0·05] and >2 for respiratory syncytial virus [p=0·01]) and a reduction in PEF of more than 12 L/min for picornavirus (p=0·04) for high compared with low NO2 exposure before the start of the virus-induced exacerbation.InterpretationHigh exposure to NO2 in the week before the start of a respiratory viral infection, and at levels within current air quality standards, is associated with an increase in the severity of a resulting asthma exacerbation.

Measurements of Personal Exposure to Nitrogen Dioxide in Four Mexican Cities in 1996

Nitrogen dioxide is a ubiquitous pollutant in urban areas. Indoor NO2 concentrations are influenced by penetration of outdoor concentrations and by indoor sources. The objectives of this study were to evaluate personal exposure to NO2, taking into account human time-activity patterns in four Mexican cities. Passive filter badges were used for indoor, outdoor, and personal NO2 measurements over 48 hr and indoor workplace measurements over 16 hr. Volunteers completed a questionnaire on exposure factors and a time-activity diary during the sample period. An unpaired t test, an analysis of variance (ANOVA), and a linear regression were performed to compare differences among cities and mean personal NO2 concentrations involving housing characteristics, as well as to determine which variables predicted the personal NO2 concentration. Sampling periods were in April, May, and June 1996 in Mexico City, Guadalajara, Cuernavaca, and Monterrey. All 122 volunteers in the study were working adults, with a mean age of 34 (SD ± 7.38); 64% were female, and the majority worked in public offices and universities. The highest NO2 concentrations were found in Mexico City (36 ppb for outdoor, 57 ppb for indoor, and 39 ppb for personal concentration) and the lowest in Monterrey (19 ppb for outdoor, 24 ppb for indoor, and 24 ppb for personal concentration). Significant differences in NO2 concentrations were found among the cities in different microenvironments. During the sampling period, volunteers spent 85% of their time indoors. The highest personal NO2 concentration was found when volunteers kept their windows closed (p = 0.03). In the regression model adjusted by city and gender, the best predictors of personal NO2 concentration were outdoor levels and time spent outdoors (R2 = 0.68). These findings suggest that outdoor NO2 concentrations were an important influence on the personal exposure to NO2, due to the specific characteristics and personal behavior of the people in these Mexican cities.

Factors affecting individual exposure to NO2 in Genoa (northern Italy).

The individual exposure to nitrogen dioxide (NO2) of 89 volunteers living in Genoa, a large port city of northern Italy, was investigated with personal passive diffusion tubes in February-March 2000. The data were related to NO2 concentration in the kitchen and bedroom as measured by static samplers. Volunteers included students, workers and housewives living in three areas of Genoa differing by street traffic and industrial plant location. The kitchen samples showed higher (47.00+/-16.5 microg/m3) NO2 concentrations than those from the bedroom (24.78+/-9.8 microg/m3); overall indoor NO2 concentrations were lower in the Eastern area of Genoa, where outdoor pollution is lower. Students were the volunteer group with the lowest exposure rate (24.9+/-7.8 microg/m3 vs. 44.3+/-10.1 microg/m3 for workers and 40.0+/-13.4 microg/m3 for housewives). This difference is related to the fact that students spend more time indoors, where pollution levels are lower. The main household characteristics which were shown to affect personal NO2 exposure were (a) the presence of a chimney equipped with an active aspiration device in the kitchen and (b) the heating system.

Road traffic, NO&lt;SUB align=right&gt;2 exposure and respiratory function among children (VESTA study)

Within the multicentre VESTA case-control study on childhood asthma and traffic air pollution, we studied the association between the respiratory function and NO2 personal exposures or intensity of traffic close to homes and schools. The relative contribution of different indoor and outdoor emission sources on personal NO2 exposures was also assessed. The respiratory function (forced expiratory volume in one second - FEV1 - and peak expiratory flow rate - PEFR) was measured with a One-Flow tester R. NO2 personal exposure was measured using passive Ogawa samplers that were worn during 48 hours by study participants, aged four to 14 years old. Exposure to traffic exhausts was assessed through an index based on a time-weighted average of traffic density to road distance ratios. The most influential variables that predicted NO2 personal exposures were the traffic index, use of a gas cooker at home and background ambient air pollution, with variable associations across cities (model R2 rank from 0.33 to 0.67). No association was found between the respiratory function and the levels of NO2 personal exposure; FEV1 or PEFR values, however, were associated with the traffic index, in two out of four cities. These results suggest that cumulative exposure to traffic exhausts may alter the respiratory function of children.

Personal exposures of children to nitrogen dioxide relative to concentrations in outdoor air

OBJECTIVESTo investigate the relation between fluctuations in personal exposure to nitrogen dioxide (NO2) in school children and changes in outdoor NO2 concentrations.METHODS114 Asthmatic school children aged 7–12 years were recruited...