The relationship between particulate air pollution and emergency hospital visits for hypertension in Beijing, China

Background

A number of epidemiological studies have examined the adverse effect of air pollution on mortality and morbidity. Also, several studies have investigated the associations between air pollution and specific-cause diseases including arrhythmia, myocardial infarction, and heart failure. However, little is known about the relationship between air pollution and the onset of hypertension.

Objective

To explore the risk effect of particulate matter air pollution on the emergency hospital visits (EHVs) for hypertension in Beijing, China.

Methods

We gathered data on daily EHVs for hypertension, fine particulate matter less than 2.5 μm in aerodynamic diameter (PM_2.5), particulate matter less than 10 μm in aerodynamic diameter (PM₁₀), sulfur dioxide, and nitrogen dioxide in Beijing, China during 2007. A time-stratified case-crossover design with distributed lag model was used to evaluate associations between ambient air pollutants and hypertension. Daily mean temperature and relative humidity were controlled in all models.

Results

There were 1,491 EHVs for hypertension during the study period. In single pollutant models, an increase in 10 μg/m³ in PM_2.5 and PM₁₀ was associated with EHVs for hypertension with odds ratios (overall effect of five days) of 1.084 (95% confidence interval (CI): 1.028, 1.139) and 1.060% (95% CI: 1.020, 1.101), respectively.

Conclusion

Elevated levels of ambient particulate matters are associated with an increase in EHVs for hypertension in Beijing, China.     

The association between fine particulate air pollution and hospital emergency room visits for cardiovascular diseases in Beijing, China

Background

Because epidemiological studies have yielded different results, the association between exposure to fine particulate matter less than 2.5 μm in aerodynamic diameter (PM_2.5) and acute events of cardiovascular diseases (CVD) is unknown. Additionally, no research has been conducted to explore the association between PM_2.5 and hospital emergency room (ER) visits of cardiovascular diseases in Beijing, China.

Objective

To explore the association between PM_2.5 and the hospital ER visits in Beijing, China for CVD {(International Classification of Diseases, 10th vision (ICD-10): I00~I99)}.

Methods

We collected data for daily hospital ER visits for CVD from the Peking University Third Hospital, daily ambient PM_2.5 data from a fixed monitor site at Peking University, and data on the daily level of gaseous air pollutants {sulfur dioxide (SO₂) and nitrogen dioxide (NO₂)} from the Beijing Municipal Environmental Monitoring Center between June 1, 2004 and December 31, 2006. A time-stratified case-crossover design was used to evaluate associations between CVD health outcomes and ambient air pollutants.

Results

8377 hospital ER visits of CVD were collected in our study. After adjusting the temperature and the relative humidity, the associations for 10 μg/m³ increases in levels of PM_2.5, SO₂, or NO₂ and hospital ER visits for cardiovascular diseases were statistically significant with odds ratios (ORs) of 1.005{95% confidence interval (CI): 1.001-1.009}, 1.014(95% CI: 1.004-1.024), and 1.016(95% CI: 1.003-1.029), respectively.

Conclusion

These findings suggest that elevated levels of ambient air pollutants are associated with the increase in hospital ER visits for CVD in Beijing, China.     

Diesel vehicle emission and death rates in Tokyo, Japan: a natural experiment

Evidence linking air pollution with adverse cardiopulmonary outcomes is accumulating. However, few studies have been conducted to evaluate whether vehicle emission control improves public health. We thus evaluated the effect of a diesel emission control law on mortality rates in 23 wards of Tokyo metropolitan area, Japan. We obtained daily counts of mortality and concentrations of nitrogen dioxide (NO₂) and particulate matter less than 2.5 μm in diameter (PM_2.5) from April 2003 to December 2008. Time-series and interrupted time-series analysis were employed to analyze the data in two periods: prior to the introduction of tighter restrictions (April 2003 to March 2006) and after the enforcement (April 2006 to December 2008). Concentrations of air pollutants gradually decreased during the study period: from 36.3 ppb (NO₂) and 22.8 μg/m³ (PM_2.5) to 32.1 ppb and 20.3 μg/m³, respectively. Air pollutants were positively associated with circulatory and pulmonary disease mortality, especially cerebrovascular disease. Each same-day PM_2.5 increase of 10 μg/m³ was associated with a 1.3% increase in cerebrovascular mortality rate (95% confidence interval: 0.2-2.4). Rate ratios were attenuated after the enforcement in most of the outcomes, probably due to reduced toxicity of the pollutants. In the crude interrupted time-series analysis, reductions of standardized mortality rates after the enforcement were the greatest in high traffic areas. Even after adjustment of longer-time trend, mortality rate from cerebrovascular disease was reduced by 8.50% (p < .001) with dose-response relationship. However, the declines in other cause-specific mortality became equivocal. This natural experiment in Tokyo suggests that emission controls improved air quality. Although suggestive, further data are needed to conclusively demonstrate an impact on mortality rates.     

Role of Saharan dust in the relationship between particulate matter and short-term daily mortality among the elderly in Madrid (Spain)

Background

Saharan dust outbreaks are a common phenomenon in the Madrid atmosphere. The current Directive 2008/50 CE governing air quality in European cities, draws no distinction between which particulate matter (PM₁₀, PM_2.5 or PM_10-2.5) would be the best indicator on days with/without Saharan dust intrusions. This study sought to identify the role played by Saharan dust in the relationship between particulate matter (PM₁₀, PM_2.5 and PM_10-2.5) concentrations and daily mortality among the elderly in the city of Madrid.

Methods

We conducted an ecological longitudinal time-series study on daily mortality among the over-75 age group, from 2003 to 2005. Poisson regression models were constructed for days with and without Saharan dust intrusions. The following causes of daily mortality were analysed: total organic causes except accidents (International Classification of Diseases-10th revision (ICD-10): A00-R99); circulatory causes (ICD-10: I00-I99); and respiratory causes (ICD-10: J00-J99). Daily mean PM₁₀, PM_2.5 and PM_10-2.5 levels were used as independent variables. Control variables were: other ambient pollutants (chemical, biotic and acoustic); trend; seasonalities; influenza epidemics; and autocorrelations between mortality series.

Results

While daily mean PM_2.5 concentrations in Madrid displayed a significant statistical association with daily mortality for all the above causes on days without Saharan dust intrusions, this association was not in evidence for PM₁₀ or PM_10-2.5 in the multivariate models. The relative risks (RRs) obtained for an increase of 10 μg/m³ in PM_2.5 concentrations were: 1.023 (1.010-1.036) for total organic causes; 1.033 (1.031-1.035) for circulatory causes; and 1.032 (1.004-1.059) for respiratory causes. On Saharan dust days, a significant statistical association was detected between PM₁₀ (though not PM_2.5 or PM_10-2.5) and mortality for all 3 causes analysed, with RRs statistically similar to those reported for PM_2.5.

Conclusions

The best air quality indicators for evaluating the short-term health effects of particulate matter in Madrid are therefore PM₁₀ concentrations on days with, and PM_2.5 concentrations on days without Saharan dust outbreaks. This fact should be taken into account in a European Directive regulating ambient air quality in almost all countries in the Mediterranean area.     

Fine particulate air pollution and daily mortality in Shenyang, China

Fine particulate matter (PM_2.5) is not a criteria pollutant in China, and few studies were conducted in the country to investigate the health impact of PM_2.5. In this study, we did a time-stratified case-crossover analysis to examine the association between PM_2.5 and daily mortality in Shenyang, an industrial center in northeast China. Daily mortality, air pollution and weather data from August 1, 2006 to December 31, 2008 in Shenyang were collected. A time-stratified case-crossover approach was used to estimate the association of PM_2.5 with both total and cause-specific mortality. Controls were selected as matched days of the week in the same month. Potential effect modifiers, such as age, gender, and season, were also examined. We found significant associations between PM_2.5 and daily mortality in Shenyang. A 10 μg/m³ increment in the 2-day moving average (lag 01) concentrations of PM_2.5 corresponded to 0.49% (95% CI: 0.19%, 0.79%), 0.53% (95% CI: 0.09%, 0.97%), and 0.97% (95% CI: 0.01%, 1.94%) increase of total, cardiovascular, and respiratory mortality, respectively. The associations appeared to be stronger in older people (aged ≥ 75 years), in females and during the warm season. To our knowledge, this is the longest PM_2.5 health study in time duration in China. Our findings provide new information on the adverse health effects of PM_2.5, and may have implications for environmental policy making and standard setting in China.     

Comparison of short-term exposure to particle number, PM10 and soot concentrations on three (sub) urban locations

Recent interest has focused on the health effects of ultrafine particles because of the documented toxicity and the larger concentration contrast near motorways of UFP than for PM10 or PM2.5. There are only few studies that have measured UFP at inner-city streets simultaneously with other PM components.The aim of this study was to compare the contrast of UFP, PM₁₀ and soot measured simultaneously at 3 inner-city locations, namely a moderately busy street (15,000 vehicles/day), a city and a suburban background location.Simultaneously, measurements of particle number concentrations (PNC), PM₁₀ and soot have been conducted on three locations in and around Utrecht, a medium-sized city in the Netherlands for 20 weekdays in autumn 2008. Measurements were done for 6-h during afternoon and early evening.The mean PNC at the street location was more than 3 times higher than at the two background locations. The contrast was similar for soot concentrations. In PM₁₀ concentrations less contrast was found, namely 1.8 times. Mean PNC concentrations were poorly correlated with PM₁₀ and soot. At the street location, high temporal variation of PNC concentrations occurred within each sampling day, probably related to variations in traffic volumes, high-emission individual vehicles and wind direction. Temporal variation was smaller at the two background locations. Occasional unexplained short-term peaks occurred at the suburban background location. A relatively high correlation between PNC minute values at the two background locations was found, pointing to similar area-wide sources. Typically low correlations were found with the street locations, consistent with the dominant impact of local traffic.A large contrast between two background locations and a moderately busy urban street location was found for PNC and soot, comparable to previous studies of much busier motorways. Temporal variation of PNC was higher at the street location and uncorrelated with background variations.     

A randomized double‐blind crossover study of indoor air filtration and acute changes in cardiorespiratory health in a First Nations community

Few studies have examined indoor air quality in First Nations communities and its impact on cardiorespiratory health. To address this need, we conducted a crossover study on a First Nations reserve in Manitoba, Canada, including 37 residents in 20 homes. Each home received an electrostatic air filter and a placebo filter for 1 week in random order, and lung function, blood pressure, and endothelial function measures were collected at the beginning and end of each week. Indoor air pollutants were monitored throughout the study period. Indoor PM_2.5 decreased substantially during air filter weeks relative to placebo (mean difference: 37 μg/m³, 95% CI: 10, 64) but remained approximately five times greater than outdoor concentrations owing to a high prevalence of indoor smoking. On average, air filter use was associated with a 217‐ml (95% CI: 23, 410) increase in forced expiratory volume in 1 s, a 7.9‐mm Hg (95% CI: ?17, 0.82) decrease in systolic blood pressure, and a 4.5‐mm Hg (95% CI: ?11, 2.4) decrease in diastolic blood pressure. Consistent inverse associations were also observed between indoor PM_2.5 and lung function. In general, our findings suggest that reducing indoor PM_2.5 may contribute to improved lung function in First Nations communities.     

Short-term effect of fine particulate matter (PM2.5) on daily mortality due to diseases of the circulatory system in Madrid (Spain)

Introduction

Owing to their small size, fine particles, i.e., those having a diameter ≤ 2.5 μm (PM_2.5), have a high alveolar penetration capacity, thereby triggering a local inflammatory process with circulatory repercussion. Despite being linked to respiratory and cardiovascular morbidities, there is limited evidence of an association between this type of particulate matter and short-term increases in mortality.

Objective

The aim of this study was to analyse and quantify the short-term impact of PM_2.5 on daily mortality due to diseases of the circulatory system, registered in Madrid from 1 January 2003 to 31 December 2005.

Methods

An ecological longitudinal time-series study was conducted, with risks being quantified by means of Poisson regression models. As a dependent variable, we took daily mortality registered in Madrid from 1 January 2003 to 31 December 2005, attributed to all diseases of the circulatory system as classified under heads I00-I99 of the International Classification of Diseases-10th revision (ICD-10) and broken down as follows: I21, acute myocardial infarction (AMI); I20, I22-I25, other ischemic heart diseases; and I60-I69, cerebrovascular diseases. The independent variable was daily mean PM_2.5 concentration. The other variables controlled for were: chemical pollution (PM₁₀, O₃, SO₂, NO₂ and NO_x); acoustic and biotic pollution; influenza; minimum and maximum temperatures; seasonalities; trend; and autocorrelation of the series.

Results

A linear relationship was observed between PM_2.5 levels and mortality due to diseases of the circulatory system. For every increase of 10 μg/m³ in daily mean PM_2.5 concentration, the relative risks (RR) were as follows: for overall circulatory mortality, associations were established at lags 2 and 6, with RR of 1.022 (1.005-1.039) and 1.025 (1.007-1.043) respectively; and for AMI mortality, there was an association at lag 6, with an RR of 1.066 (1.032-1.100). The corresponding attributable risks percent (AR%) were 2.16%, 2.47% and 6.21% respectively. No statistically significant association was found with other ischemic heart diseases or with cerebrovascular diseases.

Conclusion

PM_2.5 concentrations are an important risk factor for daily circulatory-cause mortality in Madrid. From a public health point of view, the planning and implementation of specific measures targeted at reducing these levels constitute a pressing need.     

Temporal variation of nitro-polycyclic aromatic hydrocarbons in PM10 and PM2.5 collected in Northern Mexico City

With the aim to determine the presence of individual nitro-PAH contained in particles in the atmosphere of Mexico City, a monitoring campaign for particulate matter (PM₁₀ and PM_2.5) was carried out in Northern Mexico City, from April 2006 to February 2007. The PM₁₀ annual median concentration was 65.2 μg m^− 3 associated to 7.6 μg m^− 3 of solvent-extractable organic matter (SEOM) corresponding to 11.4% of the PM₁₀ concentration and 38.6 μg m^− 3 with 5.9 μg m^− 3 SEOM corresponding to 15.2% for PM_2.5. PM concentration and SEOM varied with the season and the particle size. The quantification of nitro-polycyclic aromatic hydrocarbons (nitro-PAH) was developed through the standards addition method under two schemes: reference standard with and without matrix, the former giving the best results. The recovery percentages varied with the extraction method within the 52 to 97% range depending on each nitro-PAH. The determination of the latter was effected with and without sample purification, also termed fractioning, giving similar results. 8 nitro-PAH were quantified, and their sum ranged from 111 to 819 pg m^− 3 for PM₁₀ and from 58 to 383 pg m^− 3 for PM_2.5, depending on the season. The greatest concentration was for 9-Nitroanthracene in PM₁₀ and PM_2.5, detected during the cold-dry season, with a median (10th-90th percentiles) concentration in 235 pg m^− 3 (66-449 pg m^− 3) for PM₁₀ and 73 pg m^− 3 (18-117 pg m^− 3) for PM_2.5. The correlation among mass concentrations of the nitro-PAH and criteria pollutants was statistically significant for some nitro-PAH with PM₁₀, SEOM in PM₁₀, SEOM in PM_2.5, NO_X, NO₂ and CO, suggesting either sources, primary or secondary origin. The measured concentrations of nitro-PAH were higher than those reported in other countries, but lower than those from Chinese cities. Knowledge of nitro-PAH atmospheric concentrations can aid during the surveillance of diseases (cardiovascular and cancer risk) associated with these exposures.     

Indoor and outdoor PM2.5 and PM10 concentrations in the air during a dust storm

Asian dust storms (ADS) originating from the arid deserts of Mongolia and China are a well-known springtime meteorological phenomenon throughout East Asia. The ventilation systems in office utilize air from outside and therefore it is necessary to understand how these dust storms affect the concentrations of PM_2.5 and PM₁₀ in both the indoor and outdoor air. We measured dust storm pollution particles in an office building using a direct-reading instrument (PC-2 Quartz Crystal Microbalance, QCM) that measured particle size and concentration every 10 min for 1 h, three times a day. A three-fold increase in the concentrations of PM_2.5 and PM₁₀ in the indoor and outdoor air was recorded during the dust storms. After adjusting for other covariates, autoregression models indicated that PM_2.5 and PM₁₀ in the indoor air increased significantly (21.7 μg/m³ and 23.0 μg/m³ respectively) during dust storms. The ventilation systems in high-rise buildings utilize air from outside and therefore the indoor concentrations of fine and coarse particles in the air inside the buildings are significantly affected by outside air pollutants, especially during dust storms.     

Comparison of airflow and particulate matter transport in multi-room buildings for different natural ventilation patterns

This study numerically investigates airflow characteristics and particulate matter (PM) transport in multi-room buildings for different natural ventilation patterns with the same air change rate. Four typical natural ventilation patterns (full-open, pass-through, right short-circuit and left short-circuit), representing the ratios of the outlet-to-inlet opening size ranging from 1.67 to 0.17, are considered to study multi-room airflow characteristics. A measured indoor PM₁₀ profile in Taipei Metropolis is input into the above four ventilation patterns as the initial condition of the PM size distribution. The time variation of indoor PM₁₀/PM_2.5/PM₁ concentrations in each room for various ventilation patterns is next investigated. The effect of ventilation pattern on particle removal mechanism is emphasized. The results show that although the air change rate of the building is the same, airflow characteristics and PM transport behaviors are quite different for various ventilation patterns. The removal efficiencies of PM₁₀ for the four ventilation patterns are all found to be much better than those of PM_2.5 and PM₁. Particle escape is the major mechanism to remove PM for rooms with double-sided ventilation, whereas particle deposition is important for single-sided ventilation rooms.     

Factors affecting variability in gaseous and particle microenvironmental air pollutant concentrations in Hong Kong primary and secondary schools

School-age children are particularly susceptible to exposure to air pollutants. To quantify factors affecting children's exposure at school, indoor and outdoor microenvironmental air pollutant concentrations were measured at 32 selected primary and secondary schools in Hong Kong. Real-time PM₁₀, PM_2.5, NO_2, and O₃ concentrations were measured in 76 classrooms and 23 non-classrooms. Potential explanatory factors related to building characteristics, ventilation practice, and occupant activities were measured or recorded. Their relationship with indoor measured concentrations was examined using mixed linear regression models. Ten factors were significantly associated with indoor microenvironmental concentrations, together accounting for 74%, 61%, 46%, and 38% of variations observed for PM_2.5, PM₁₀, O_3, and NO₂ microenvironmental concentrations, respectively. Outdoor concentration is the single largest predictor for indoor concentrations. Infiltrated outdoor air pollution contributes to 90%, 70%, 75%, and 50% of PM_2.5, PM₁₀, O_3, and NO₂ microenvironmental concentrations, respectively, in classrooms during school hours. Interventions to reduce indoor microenvironmental concentrations can be prioritized in reducing ambient air pollution and infiltration of outdoor pollution. Infiltration factors derived from linear regression models provide useful information on outdoor infiltration and help address the gap in generalizable parameter values that can be used to predict school microenvironmental concentrations.     

Factors influencing relationships between personal and ambient concentrations of gaseous and particulate pollutants

Previous exposure studies have shown considerable inter-subject variability in personal-ambient associations. This paper investigates exposure factors that may be responsible for inter-subject variability in these personal-ambient associations. The personal and ambient data used in this paper were collected as part of a personal exposure study conducted in Boston, MA, during 1999-2000. This study was one of a group of personal exposure panel studies funded by the U.S. Environmental Protection Agency's National Exposure Research Laboratory to address areas of exposure assessment warranting further study, particularly associations between personal exposures and ambient concentrations of particulate matter and gaseous co-pollutants. Twenty-four-hour integrated personal, home indoor, home outdoor and ambient sulfate, elemental carbon (EC), PM_2.5, ozone (O₃), nitrogen dioxide (NO₂) and sulfur dioxide were measured simultaneously each day. Fifteen homes in the Boston area were measured for 7 days during winter and summer. A previous paper explored the associations between personal-indoor, personal-outdoor, personal-ambient, indoor-outdoor, indoor-ambient and outdoor-ambient PM_2.5, sulfate and EC concentrations. For the current paper, factors that may affect personal exposures were investigated, while controlling for ambient concentrations. The data were analyzed using mixed effects regression models. Overall personal-ambient associations were strong for sulfate during winter (p < 0.0001) and summer (p < 0.0001) and PM_2.5 during summer (p < 0.0001). The personal-ambient mixed model slope for PM_2.5 during winter but was not significant at p = 0.10. Personal exposures to most pollutants, with the exception of NO₂, increased with ventilation and time spent outdoors. An opposite pattern was found for NO₂ likely due to gas stoves. Personal exposures to PM_2.5 and to traffic-related pollutants, EC and NO₂, were higher for those individuals living close to a major road. Both personal and indoor sulfate and PM_2.5 concentrations were higher for homes using humidifiers. The impact of outdoor sources on personal and indoor concentrations increased with ventilation, whereas an opposite effect was observed for the impact of indoor sources.     

Size distribution of airborne particles controls outcome of epidemiological studies

Epidemiological studies typically using wide size range mass metrics (e.g. PM₁₀) have demonstrated associations between airborne particulate matter and several adverse health outcomes. This approach ignores the fact that mass concentration may not correlate with regional lung dose, unlike the case of trace gases. When using measured particle size distributions as the basis for calculating regional lung dose, PM₁₀ mass concentration is found to be a good predictor of the mass dose in all regions of the lung, but is far less predictive of the surface area and particle number dose. On the other hand, measurements of particle number do not well predict mass dose, indicating that the chosen particle metric is likely to determine the health outcomes detectable by an epidemiological study. Consequently, epidemiological studies using mass metrics (PM_2.5 and PM₁₀) may fail to recognise important health consequences of particulate matter exposure, leading to an underestimate of the public health consequences of particle exposure.     

Exposures to PM₂.₅ components and heart rate variability in taxi drivers around the Beijing 2008 Olympic Games

Background

Carbonaceous and metallic components of particles have been shown to play a role in particles' effects on cardiac autonomic function as measured by heart rate variability (HRV). Previously we reported the association of HRV with marked changes in traffic-related particulate air pollution around the Beijing 2008 Olympic Games in a panel of taxi drivers.

Objective

We further investigated the relationship between exposures to the carbonaceous and metallic components of traffic-related particles and HRV in the same population.

Methods

Repeated measurements of in-car exposures to particulate matter ≤ 2.5 μm in aerodynamic diameter (PM_2.5), carbon monoxide and nitrogen oxides were conducted in a group of 14 taxi drivers for one work shift in four study periods around the Beijing 2008 Olympics. The quantities of organic/elemental carbons and 27 elements of the in-car PM_2.5 mass were determined laboratorially. Linear mixed-effects models were used to evaluate the impact of exposures to different PM_2.5 components on HRV while controlling for potential confounders.

Results

Taxi drivers' exposures to in-car PM_2.5 and its components showed dramatic changes across the four study periods around the Beijing 2008 Olympics. Differences in associations of in-car PM_2.5 components with HRV were found. An interquartile range (IQR: 917.9 ng/m³) increase in calcium was associated with a 5.48 millisecond [ms, 95% confidence interval (CI): 0.71, 10.24] increase in standard deviations of normal-to-normal (SDNN) intervals, while an IQR (4.1 ng/m³) increase in nickel was associated with a 1.53 ms (95% CI: 0.14, 2.92) increase in SDNN index. Additionally, a decline of 8.11 ms (95% CI: − 15.26, − 0.97) in SDNN per IQR (481.4 ng/m³) increase in iron was also found.

Conclusion

The results support associations of PM_2.5 metallic components with HRV in younger healthy individuals. Future studies are needed to clarify the interaction among different PM_2.5 components or the role of PM_2.5 mixtures.     

Size distribution and chemical composition of airborne particles in south-eastern Finland during different seasons and wildfire episodes in 2006

The inorganic main elements, trace elements and PAHs were determined from selected PM₁, PM_2.5 and PM₁₀ samples collected at the Nordic background station in Virolahti during different seasons and during the wildfire episodes in 2006. Submicron particles are those most harmful to human beings, as they are able to penetrate deep into the human respiratory system and may cause severe health effects. About 70-80%, of the toxic trace elements, like lead, cadmium, arsenic and nickel, as well as PAH compounds, were found in particles smaller than 1 µm. Furthermore, the main part of the copper, zinc, and vanadium was associated with submicron particles. In practice, all the PAHs found in PM₁₀ were actually in PM_2.5. For PAHs and trace elements, it is more beneficial to analyse the PM_2.5 or even the PM₁ fraction instead of PM₁₀, because exclusion of the large particles reduces the need for sample cleaning to minimize the matrix effects during the analysis. During the wildfire episodes, the concentrations of particles smaller than 2.5 µm, as well as those of submicron particles, increased, and also the ratio PM₁/PM₁₀ increased to about 50%. On the fire days, the mean potassium concentration was higher in all particle fractions, but ammonium and nitrate concentrations rose only in particles smaller than 1.0 µm. PAH concentrations rose even to the same level as in winter.     

Particulate matter and gaseous pollutants in residences in Antwerp, Belgium

This comprehensive study, a first in Flanders, Belgium, aimed at characterizing the residential indoor air quality of subgroups that took part in the European Community Respiratory Health Survey (ECRHS I—1991 and ECHRS II—1996) questionnaire-based asthma and related illnesses studies. This pilot study aimed at the evaluation of particulate matter and various inorganic gaseous compounds in residences in Antwerp. In addition personal exposure to the gaseous compounds of one individual per residence was assessed. The main objective was to obtain some base-line pollutant levels and compare these with studies performed in other cities, to estimate the indoor air quality in residences in Antwerp. Correlations between the various pollutant levels, indoor:outdoor ratios and the micro-environments of each residence were investigated. This paper presents results on indoor and ambient PM₁, PM_2.5 and PM₁₀ mass concentrations, its elemental composition in terms of K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Pb, Al, Si, S and Cl and the water-soluble ionic concentrations in terms of SO₄²⁻, NO₃²⁻, Cl⁻, NH₄⁺ K⁺, Ca²⁺. In addition, indoor, ambient and personal exposure levels of the gases NO₂, SO₂, and O₃ were determined. Elevated indoor:outdoor ratios were found for NO₂ in residences containing gas stoves. In smoker's houses increased PM concentrations of 58 and 43% were found for the fine and coarse fractions respectively. Contrary to the fact that all I/O ratios of the registered elements in each individual house were significantly correlated to each other, no correlation could be established between the I/O ratios of the different houses, thus indicating a unique micro-environment for each residence. Linear relationships between the particulate matter elemental composition, SO₂ and O₃ levels indoors and outdoors could be established. No linear relationships between indoor and outdoor NO₂ and particulate mass concentrations were found.     

Effects of agriculture crop residue burning on children and young on PFTs in North West India

Variations in pulmonary function tests (PFTs) due to agriculture crop residue burning (ACRB) on children between the age group of 10 to 13 years and the young between 20 to 35 years are studied. The effects of exposure to smoke due to rice-wheat crop residue burning on pulmonary functions like Force Vital Capacity (FVC), Force Expiratory Volume in one second (FEV₁), Peak Expiratory Flow (PEF) and Force Expiratory Flow in 25 to 75% of FVC (FEF_25-75%) on 40 healthy subjects of rural/agricultural area of Sidhuwal village of Patiala City were investigated for a period from August 2008 to July 2009. Measurements were taken by spirometry according to the American Thoracic Society standards. High volume sampler (HVS) and Anderson Impactor were used to measure the concentration levels of SPM, PM₁₀ and PM_2.5 in ambient air of the Sidhuwal village. A significant increase in the concentration levels of SPM, PM₁₀ and PM_2.5 was observed due to which PFTs of the subjects showed a significant decrease in their values, more prominently in the case of children. PFTs of young subjects recovered up to some extent after the completion of burning period but the PFT values of children remained significantly lower (p < 0.001) even after the completion of burning episodes. Small size particulate matter (PM_2.5 and PM₁₀) affected the PFTs to a large extent in comparison to the large size particulate matter (SPM). The study indicates that ACRB is a serious environmental health hazard and children are more sensitive to air pollution, as ACRB poses some unrecoverable influence on their PFTs.     

Associations of PM2.5 and black carbon concentrations with traffic, idling, background pollution, and meteorology during school dismissals

An air quality study was performed outside a cluster of schools in the East Harlem neighborhood of New York City. PM_2.5 and black carbon concentrations were monitored using real-time equipment with a one-minute averaging interval. Monitoring was performed at 1:45-3:30 PM during school days over the period October 31-November 17, 2006. The designated time period was chosen to capture vehicle emissions during end-of-day dismissals from the schools. During the monitoring period, minute-by-minute volume counts of idling and passing school buses, diesel trucks, and automobiles were obtained. These data were transcribed into time series of number of diesel vehicles idling, number of gasoline automobiles idling, number of diesel vehicles passing, and number of automobiles passing along the block adjacent to the school cluster. Multivariate regression models of the log-transform of PM_2.5 and black carbon (BC) concentrations in the East Harlem street canyon were developed using the observation data and data from the New York State Department of Environmental Conservation on meteorology and background PM_2.5. Analysis of variance was used to test the contribution of each covariate to variability in the log-transformed concentrations as a means to judge the relative contribution of each covariate. The models demonstrated that variability in background PM_2.5 contributes 80.9% of the variability in log[PM_2.5] and 81.5% of the variability in log[BC]. Local traffic sources were demonstrated to contribute 5.8% of the variability in log[BC] and only 0.43% of the variability in log[PM_2.5]. Diesel idling and passing were both significant contributors to variability in log[BC], while diesel passing was a significant contributor to log[PM_2.5]. Automobile idling and passing did not contribute significant levels of variability to either concentration. The remainder of variability in each model was explained by temperature, along-canyon wind, and cross-canyon wind, which were all significant in the models.     

Metal concentration of PM2.5 and PM10 particles and seasonal variations in urban and rural environment of Agra, India

Three monthly 24-hour samples of airborne aerosols (PM₁₀ and PM_2.5) were collected at an urban and a rural site of the North central, semi-arid part of India during May 2006 to March 2008. Seven trace metals (Pb, Zn, Ni, Fe, Mn, Cr and Cu) were determined for both sizes. The annual mean concentration for PM₁₀ was 154.2 µg/m³ and 148.4 µg/m³ at urban and rural sites whereas PM_2.5 mean concentration was 104.9 µg/m³ and 91.1 µg/m³ at urban and rural sites, respectively. Concentrations of PM₁₀ and PM_2.5 have been compared with prescribed WHO standards and NAAQS given by CPCB India and were found to be higher. Weekday/weekend variations of PM₁₀ and PM_2.5 have been studied at both monitoring sites. Lower particulate pollutant levels were found during weekends, which suggested that anthropogenic activities are major contributor of higher ambient particulate concentration during weekdays. Significant seasonal variations of particulate pollutants were obtained using the daily average concentration of PM₁₀ and PM_2.5 during the study period. PM_2.5/PM₁₀ ratios at urban and rural sites were also determined during the study period, which also showed variation between the seasons. Three factors have been identified using Principal Component Analysis at the sampling sites comprising resuspension of road dust due to vehicular activities, solid waste incineration, and industrial emission at urban site whereas resuspension of soil dust due to vehicular emission, construction activities and wind blown dust carrying industrial emission, were common sources at rural site.