Major Outdoor Air Pollutants Research Articles

UiO66-Derived Catalyst for Low Temperature Catalytic Reduction of NO with NH3.

Diesel exhaust emissions are major outdoor air pollutants. Reducing the emission of NOx by diesel commercial vehicles and related machineries is at present a great challenge. In this study, we synthesize a catalyst for low-temperature catalytic reduction of NO using calcinated UiO-66(Zr) as a host for the doping of cerium, manganese, and titanium by the incipient wetness impregnation, followed by the dispersion of 1.0 wt % platinum. A solid solution of Ce0.15Zr0.54Mn0.11Ti0.20O2/1.0Pt (CZMTO/Pt) is synthesized as evident by the structural characterizations. The catalyst demonstrates significant NO reduction in the laboratory due to the synergistic effect of various elements, with NO conversion above 80% at 160 °C.

Effects of long-term exposure to major outdoor air pollutants for the risk of chronic inflammatory airway diseases in adults with potential interaction detection in Taiwan Biobank

BackgroundResearch on the association between chronic inflammatory airway diseases (CIADs), defined as asthma, chronic obstructive pulmonary disease, and impaired lung function, and long-term exposure of outdoor air pollutants for adults has been scarce. Research questionEffects of long-term exposure for outdoor air pollutants to the risk of CIADs in adults. Materials and methodsApplying data from Taiwan Biobank, 10-year accumulative exposure of major outdoor air pollutants, PM2.5, PM10, NO2, SO2, CO, and O3, was estimated by Kriging's interpolation, based on 76 nationwide air pollution monitoring stations linked to residency information at township or district level at baseline interview for volunteered community participants older than 30 years old. Eligible cases and randomly selected healthy controls constructed a nested case-control study with frequency matching on age and sex at a ratio of 1:4. We adopted logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of outdoor air pollutants to the risk of CIADs for univariable and multivariable analyses. For detecting potential interactions among critical covariates, we used the generalized multifactor dimensionality reduction method. ResultsHigher 10-year cumulative exposure of NO2 and SO2 put people at a significantly elevated relative risk of CIADs after confounding control, showing adjusted ORs of 1.07 (95% CI: 1.01, 1.14) for NO2 and 1.23 (95% CI: 1.15, 1.31) for SO2 for each increment of standard deviation. Furthermore, a significant synergistic interaction (P-value < 0.01 for interaction term) between PM10 and CO in tertiles was detected with an adjusted OR of 5.01 (95% CI: 2.95, 8.49) for the highest tertiles of PM10 and CO combined, relative to the group of lowest tertile combination. ConclusionOur outcomes contributed to a more profound understanding on the effects of long-term exposure of air pollutants to CIADs in etiology, highlighting a synergistic interaction between PM10 and CO.

Regional difference and related cooling electricity savings of air pollutant affected natural ventilation in commercial buildings across the US

Maintaining indoor air pollutants under acceptable levels is significant to protect occupants from exposure to excessive air pollutants in natural ventilation. In this paper, using the representative air pollutant concentration data, we present the natural ventilation usability with associated cooling energy saving potentials in different location settings (urban and city center, suburban and rural) of the US under the influence of local weather conditions and major outdoor air pollutants, i.e. PM2.5, PM10 and ozone. It is found that the impacts of air pollutants on natural ventilation are usually higher in urban/suburban areas than rural areas (up to 25% difference) with the PM2.5 being the most significant outdoor air pollutant affecting natural ventilation usage. Ozone could become increasingly influential on natural ventilation as moving from urban to suburban/rural areas. As to the cooling energy saving considering the impacts of outdoor air pollutants, natural ventilation is estimated to save approximately 10%–40% cooling energy (800–2600 kWh per small commercial building) annually in different location settings of investigated areas across the US. The following economic analysis demonstrates that these electricity savings lead to approximately 80–540 dollars annual savings of building operation cost per building. If the time of use rate is adopted, these cost savings could further increase by approximately 20% (Los Angeles) to more than 50% (Albuquerque) depending on different rate structures, which further demonstrates the potential of adopting natural ventilation as a sustainability measurement with benefits for building owners without compromising occupants health.

Impact of outdoor air quality on the natural ventilation usage of commercial buildings in the US

Natural ventilation has emerged as a desirable feature of sustainable buildings given its potential positive impact on building energy performance and amenities for occupants. In some circumstances, natural ventilation can provide a higher ventilation rate compared to mechanical ventilation, thus improving the air quality of indoor space, resulting in lower indoor carbon dioxide and volatile organic compound concentrations. However, this increased ventilation rate also raises the issue of increased indoor pollutant concentration from outdoor sources, which has been proven to significantly affect occupant health. In this paper, we investigate the influence of three major outdoor air pollutants, PM2.5, PM10, and ozone, on natural ventilation usage across 12 major US cities and their corresponding climate zones utilizing the outdoor air pollutant records from the US Environmental Protection Agency. Firstly, a descriptive statistics study presents a general description of air pollutant records in these investigated cities and climate zones. Then two natural ventilation operation scenarios (considering outdoor air pollutants vs. not) are developed and compared to explicitly show the expected natural ventilation reduction in these areas. The investigation results indicate that the most polluted area for natural ventilation is Los Angeles (with a projected 70% reduction), followed by Chicago (approximately 40% reduction), and then Atlanta and San Francisco (20–30% reduction for each). The natural ventilation reduction caused by outdoor air pollutants ranges from 5% to 20% in all other tested cities. Among the three pollutants (PM2.5, PM10, and ozone) we investigated, the influence of PM2.5 consistently emerges as the most critical to consider, while the impact of PM10 is typically trivial. The influence of ozone is not obvious in most cases. Nevertheless, in certain cases, its influence is non-negligible when natural ventilation is utilized. This study aims to provide a general guideline for decision makers to consider the influence of outdoor air quality on natural ventilation usage when adopting natural ventilation in different US locations. The results also confirmed the outdoor air pollutants, especially PM2.5, as a significant factor to consider in the natural ventilation design to shield the occupant from excessive air pollutant exposure.

Short-term relationships between emergency hospital admissions for respiratory and cardiovascular diseases and fine particulate air pollution in Beirut, Lebanon

High levels of major outdoor air pollutants have been documented in Lebanon, but their health effects remain unknown. The Beirut Air Pollution and Health Effects study aimed to determine the relationship between short-term variations in ambient concentrations of particulate matter (PM10 and PM2.5) and emergency hospital admissions in the city of Beirut, and whether susceptible groups are more greatly affected. An autoregressive Poisson model was used to evaluate the association between daily concentrations of particulate matter and respiratory and cardiovascular emergency hospital admissions after controlling for confounders. All variables were measured during 1 year from January 2012 to December 2012. Relative risks of admissions for respiratory and cardiovascular diseases were calculated for an increase in 10 μg.m(-3) of pollutant concentrations. Total respiratory admissions were significantly associated with the levels of PM10 (1.012 [95% CI 1.004-1.02]) per 10 μg.m(-3) rise in daily mean pollutant concentration for PM10 and 1.016 [95% CI 1.000-1.032] for PM2.5 on the same day. With regard to susceptible groups, total respiratory admissions were associated with PM2.5 and PM10 within the same day in children (relative risk (RR), 1.013 and 1.014; 95% confidence interval, 0.985-1.042 and 1.000-1.029 for PM2.5 and PM10, respectively). Moreover, a nearly significant association was found between particles and total circulatory admissions for adults and elderly groups in the same day. These results are similar to other international studies. Therefore, air pollution control is expected to reduce the number of admissions of these diseases in Lebanon.

Application of land use regression for estimating concentrations of major outdoor air pollutants in Jinan, China

SO2, NO2, and PM10 are the major outdoor air pollutants in China, and most of the cities in China have regulatory monitoring sites for these three air pollutants. In this study, we developed a land use regression (LUR) model using regulatory monitoring data to predict the spatial distribution of air pollutant concentrations in Jinan, China. Traffic, land use and census data, and meteorological and physical conditions were included as candidate independent variables, and were tabulated for buffers of varying radii. SO2, NO2, and PM10 concentrations were most highly correlated with the area of industrial land within a buffer of 0.5 km (R2=0.34), the distance from an expressway (R2=0.45), and the area of residential land within a buffer of 1.5 km (R2=0.25), respectively. Three multiple linear regression (MLR) equations were established based on the most significant variables (p<0.05) for SO2, NO2, and PM10, and R2 values obtained were 0.617, 0.640, and 0.600, respectively. An LUR model can be applied to an area with complex terrain. The buffer radii of independent variables for SO2, NO2, and PM10 were chosen to be 0.5, 2, and 1.5 km, respectively based on univariate models. Intercepts of MLR equations can reflect the background concentrations in a certain area, but in this study the intercept values seemed to be higher than background concentrations. Most of the cities in China have a network of regulatory monitoring sites. However, the number of sites has been limited by the level of financial support available. The results of this study could be helpful in promoting the application of LUR models for monitoring pollutants in Chinese cities.

Air pollutant effects on fetal and early postnatal development

Numerical research on the health effects of air pollution has been published in the last decade. Epidemiological studies have shown that children's exposure to air pollutants during fetal development and early postnatal life is associated with many types of health problems including abnormal development (low birth weight [LBW], very low birth weight [VLBW], preterm birth [PTB], intrauterine growth restriction [IUGR], congenital defects, and intrauterine and infant mortality), decreased lung growth, increased rates of respiratory tract infections, childhood asthma, behavioral problems, and neurocognitive decrements. This review focuses on the health effects of major outdoor air pollutants including particulates, carbon monoxide (CO), sulfur and nitrogen oxides (SO(2), NOx), ozone, and one common indoor air pollutant, environmental tobacco smoke (ETS). Animal data is presented that demonstrate perinatal windows of susceptibility to sidestream smoke, a surrogate for ETS, resulting in altered airway sensitivity and cell type frequency. A study of neonatal monkeys exposed to sidestream smoke during the perinatal period and/or early postnatal period that resulted in an altered balance of Th1-/Th2-cytokine secretion, skewing the immune response toward the allergy-associated Th2 cytokine phenotype, is also discussed.

Epidemiological analyses of the relationship between environmental pollution and asthma

Epidemiological studies performed on children and young adults indicate that the prevalence of asthma has increased over the past decades in a number of countries. Since genetic determinants alone are unlikely to explain these findings, environmental factors are expected to have an important impact on the prevalence of this disease. Environmental pollution, among many other factors, may play a role in the initiation and manifestation of asthma. However, there is little epidemiological evidence for a causal association between the classical major outdoor air pollutants, such as SO2 or particulate matter, and asthma. Evidence for an association between air pollution from motor vehicles and asthma is still controversial. Thus the indoor environment and other environmental determinants — including lifestyle factors — are likely to be more important as causes of asthma. Epidemiological studies are able to evaluate the effects of environmental factors on the health of human populations in their usual environments. In addition, they can measure associations between long-term environmental exposures and health outcomes. By using refined techniques for exposure and disease assessment, as well as time and cost-effective study designs, environmental epidemiology will increase the knowledge about the role of pollution as a possible cause of asthma.

Air pollution and daily mortality in Sydney, Australia, 1989 through 1993.

This study examined the effects of outdoor air pollutants in Sydney, Australia, on daily mortality. Time-series analysis was performed on counts of daily mortality and major outdoor air pollutants (particulates, ozone, and nitrogen dioxide) in Sydney (1989 to 1993) with adjustment for seasonal and cyclical factors. Poisson regression was calculated with allowance for overdispersion and autocorrelation. The effects of lagging exposure by 0 to 2 days were assessed with single- and multiple-pollutant models. An increase in daily mean particulate concentration from the 10th to the 90th centile was associated with an increase of 2.63% (95% confidence interval 0.87 to 4.41) in all-cause mortality and 2.68% (0.25 to 5.16) in cardiovascular mortality. An increase in daily maximum 1-hour ozone concentration from the 10th to the 90th centile was associated with an increase of 2.04% (0.37 to 3.73) in all-cause mortality and 2.52% (-0.25 to 5.38) in cardiovascular mortality. An increase in the daily mean nitrogen dioxide concentration from the 10th to the 90th centile was associated with an increase of 7.71% (-0.34 to 16.40) in respiratory mortality. Multiple-pollutant models suggest that the effects of particulates and ozone on all-cause and cardiovascular mortality, and of nitrogen dioxide on respiratory mortality, are independent of the effects of the other pollutants. Current levels of air pollution in Sydney are associated with daily mortality.