Air Pollution Patterns Research Articles

Correlations between short-term mobile monitoring and long-term passive sampler measurements of traffic-related air pollution

Mobile monitoring has provided a means for broad spatial measurements of air pollutants that are otherwise impractical to measure with multiple fixed site sampling strategies. However, the larger the mobile monitoring route the less temporally dense measurements become, which may limit the usefulness of short-term mobile monitoring for applications that require long-term averages. To investigate the stationarity of short-term mobile monitoring measurements, we calculated long term medians derived from a mobile monitoring campaign that also employed 2-week integrated passive sampler detectors (PSD) for NOx, Ozone, and nine volatile organic compounds at 43 intersections distributed across the entire city of Baltimore, MD. This is one of the largest mobile monitoring campaigns in terms of spatial extent undertaken at this time. The mobile platform made repeat measurements every third day at each intersection for 6–10 min at a resolution of 10 s. In two-week periods in both summer and winter seasons, each site was visited 3–4 times, and a temporal adjustment was applied to each dataset. We present the correlations between eight species measured using mobile monitoring and the 2-week PSD data and observe correlations between mobile NOx measurements and PSD NOx measurements in both summer and winter (Pearson's r = 0.84 and 0.48, respectively). The summer season exhibited the strongest correlations between multiple pollutants, whereas the winter had comparatively few statistically significant correlations. In the summer CO was correlated with PSD pentanes (r = 0.81), and PSD NOx was correlated with mobile measurements of black carbon (r = 0.83), two ultrafine particle count measures (r = 0.8), and intermodal (1–3 μm) particle counts (r = 0.73). Principal Component Analysis of the combined PSD and mobile monitoring data revealed multipollutant features consistent with light duty vehicle traffic, diesel exhaust and crankcase blow by. These features were more consistent with published source profiles of traffic-related air pollutants than features based on the PSD data alone. Short-term mobile monitoring shows promise for capturing long-term spatial patterns of traffic-related air pollution, and is complementary to PSD sampling strategies.

Micromap plots to visualize air pollution at national and local level in Korea

Air pollution is a persistent and pervasive environmental problem with health implications and economic costs for society. In this study, we introduce a new approach for visualizing air pollution data and describe how spatial patterns of air pollutants can be examined simultaneously using linked micromap plots. To explore the potential utility of the plots, we analysed and visualized Korean air pollution data for the period 1989–2012 at national and local level. Our analysis revealed that sulphur dioxide (SO2), fine particle and carbon monoxide decreased for the period, but ozone increased uniquely. The pollution level of Jeju was lowest. Daegu and Gyeonggi showed the highest levels. Daegu had highest values in both range and interquartile range. SO2 decreased the most in Gangwon which had formerly had the largest number of coal mines. Regions with high levels of fine particles were located mainly in the northwest, probably influenced by dust, and in the southeast, industrialized areas.

Evidence for increases in vegetation species richness across UK Environmental Change Network sites linked to changes in air pollution and weather patterns

We analysed trends in vegetation monitored at regular intervals over the past two decades (1993–2012) at the twelve terrestrial Environmental Change Network (ECN) sites. We sought to determine the extent to which flora had changed and link any such changes to potential environmental drivers. We observed significant increases in species richness, both at a whole network level, and when data were analysed within Broad Habitat groupings representing the open uplands, open lowlands and woodlands. We also found comparable increases in an indicator of vegetation response to soil pH, Ellenberg R. Species characteristic of less acid soils tended to show more consistent increases in frequency across sites relative to species with a known tolerance for strongly acidic soils. These changes are, therefore, broadly consistent with a response to increases in soil solution pH observed for the majority of ECN sites that, in turn, are likely to be driven by large reductions in acid deposition in recent decades. Increases in species richness in certain habitat groupings could also be linked to increased soil moisture availability in drier lowland sites that are likely to have been influenced by a trend towards wetter summers in recent years, and possibly also to a reduction in soil nitrogen availability in some upland locations. Changes in site management are also likely to have influenced trends at certain sites, particularly with respect to agricultural practices. Our results are therefore indicative of widescale responses to major regional-scale changes in air pollution and recent weather patterns, modified by local management effects. The relative consistency of management of ECN sites over time is atypical of much of the wider countryside and it is therefore not appropriate to scale up these observations to infer national scale trends. Nevertheless the results provide an important insight into processes that may be operating nationally. It will now be necessary to test for the ubiquity of these changes using appropriate broader spatial scale survey data.

Air Quality, Patterns and Otolaryngology Health Effects of Air Pollutants in Beijing in 2013

We carried out a time-series analysis on daily/hourly ambient air pollutant concentrations and daily number of outpatient consultations for otolaryngology during the first year (2013) of implementation of the National Ambient Air Quality Standards in Beijing. Daily patterns of SO_2, NO_2, CO, O_3, PM_(10) and PM_(2.5) were determined and hourly characteristics of air pollutants from Dongsi are discussed. Health effects of air pollutants on ear, nose and throat (ENT) were evaluated. The results show that daily air pollutant concentrations had obvious seasonal differences. O_3 levels in the warm season were higher than in the cold season, whereas other pollutants showed opposite trends. All pollutants had different seasonal patterns for hourly concentrations. Hours with peak concentrations also had seasonal differences, and hourly time trends of PM_(2.5) and PM_(10) (particulate matter with an aerodynamic diameters less than 2.5 μm and 10 μm, respectively) were different. In contrast with other air pollutants, hourly O_3 concentrations in warm season were higher than cold season. Dongcheng District had high PM_(10) and PM_(2.5) levels and Beijing experienced heavy PM_(2.5) pollution in 2013. Ozone became the second main air pollutant in Beijing. All pollutants had health effects on ENT, and lag effects were found for some pollutants. Relative risks in the warm season were higher than in the cold season for O_3 and lower than the cold season for the other five air pollutants.

Air pollution in Bangalore, India: an eight-year trend analysis

Bangalore is one of India's fastest growing metropolises and, although benefiting economically due to its fast development, has a rapidly deteriorating environment. This paper provides a critical analysis of the air pollution trend in the city over the period 2006-2013 at six specific locations where measurements have been consistently recorded. It also discusses the potential health implications pertaining to exceeding levels of pollutants where these are applicable. In order to attain informed decisions on the protection of the health of populations from elevated levels of air pollution, an understanding of spatial-temporal variance of air pollutant patterns is necessary. The study highlights the fact that Bangalore and other similar developing cities do not have an adequate number of fixed monitoring stations that could provide a complete coverage of the air pollution levels for the entire city. It is suggested that this can be overcome by using geospatial interpolation techniques that provide a complete coverage of the levels of pollutants, as well as assist in mapping health characteristics of the population, in order to reach evidence-based decisions and target effective interventions.

Identification of air pollution patterns using a modified fuzzy co-occurrence pattern mining method

Spatio-temporal co-occurrence patterns represent subsets of object types which are located together in both space and time. Discovering spatio-temporal co-occurrence patterns is an important task having many application domains. There are a number of developed methods to mine co-occurrence patterns; however, using them needs a unique parameter to define the neighborhood. Identification of a unique optimum k-value or neighborhood radius is a challenging issue in different application domains. The developed method of this research defines a new fuzzy neighborhood and new fuzzy metrics to be applicable for real applications such as air pollution, especially when the researchers have no comprehensive knowledge regarding the application domain; in addition, it mines patterns based on the fuzzy nature of environmental phenomena. The new method mines patterns locally without localization step to speed up the mining process and considers all feature types (point, line and polygon) to handle all applications. Subsequently, it is applied to a real data set of Tehran city for air pollution to discover significant co-occurrence patterns of air pollution and influencing environmental parameters such as meteorological, topography and traffic. The case study results showed seven meaningful patterns among air pollution classes 2 and 3 and wind speed class 1, topography class 1 and traffic classes 1 and 2. The evaluation confirmed the accuracy and applicability of the new developed method for air pollution case. Furthermore, two performance tests for the method itself and a performance test against a crisp method were done, where the results exhibited an efficient computational performance.

Occurrence and Concentrations of Toxic VOCs in the Ambient Air of Gumi, an Electronics-Industrial City in Korea.

This study was carried out to characterize the occurrence and concentrations of a variety of volatile organic compounds (VOCs) including aliphatic, aromatic, halogenated, nitrogenous, and carbonyl compounds, in the ambient air of Gumi City, where a large number of electronics industries are found. Two field monitoring campaigns were conducted for a one year period in 2003/2004 and 2010/2011 at several sampling sites in the city, representing industrial, residential and commercial areas. More than 80 individual compounds were determined in this study, and important compounds were then identified according to their abundance, ubiquity and toxicity. The monitoring data revealed toluene, trichloroethylene and acetaldehyde to be the most significant air toxics in the city, and their major sources were mainly industrial activities. On the other hand, there was no clear evidence of an industrial impact on the concentrations of benzene and formaldehyde in the ambient air of the city. Overall, seasonal variations were not as distinct as locational variations in the VOCs concentrations, whereas the within-day variations showed a typical pattern of urban air pollution, i.e., increase in the morning, decrease in the afternoon, and an increase again in the evening. Considerable decreases in the concentrations of VOCs from 2003 to 2011 were observed. The reductions in the ambient concentrations were confirmed further by the Korean PRTR data in industrial emissions within the city. Significant decreases in the concentrations of benzene and acetaldehyde were also noted, whereas formaldehyde appeared to be almost constant between the both campaigns. The decreased trends in the ambient levels were attributed not only to the stricter regulations for VOCs in Korea, but also to the voluntary agreement of major companies to reduce the use of organic solvents. In addition, a site planning project for an eco-friendly industrial complex is believed to play a contributory role in improving the air quality of the city.

A Novel Approach in Quantifying the Effect of Urban Design Features on Local-Scale Air Pollution in Central Urban Areas.

Differences in urban design features may affect emission and dispersion patterns of air pollution at local-scales within cities. However, the complexity of urban forms, interdependence of variables, and temporal and spatial variability of processes make it difficult to quantify determinants of local-scale air pollution. This paper uses a combination of dense measurements and a novel approach to land-use regression (LUR) modeling to identify key controls on concentrations of ambient nitrogen dioxide (NO2) at a local-scale within a central business district (CBD). Sixty-two locations were measured over 44 days in Auckland, New Zealand at high density (study area 0.15 km(2)). A local-scale LUR model was developed, with seven variables identified as determinants based on standard model criteria. A novel method for improving standard LUR design was developed using two independent data sets (at local and "city" scales) to generate improved accuracy in predictions and greater confidence in results. This revised multiscale LUR model identified three urban design variables (intersection, proximity to a bus stop, and street width) as having the more significant determination on local-scale air quality, and had improved adaptability between data sets.

Redesigning healthcare systems to meet the health challenges associated with climate change in the twenty-first century.

In the twenty-first century, climate change is emerging as a significant threat to the health and well-being of the public through links to the following: extreme weather events, sea level rise, temperature-related illnesses, air pollution patterns, water security, food security, vector-borne infectious diseases, and mental health effects (as a result of extreme weather events and climate change-induced population displacement). This article discusses how national healthcare systems can be redesigned through changes in its components such as human resources, facilities and technology, health information system, and health policy to meet these challenges.

Diurnal variations in the spatial patterns of air pollution across Delhi

In the present study, we have analyzed the spatial patterns of seasonal-scale diurnal cycle of three main pollutants, NO2, SO2, and O3, across five stations in Delhi. We used hourly data collected by the local pollution monitoring agencies for the time period, October 2010 to September 2013. Harmonic analysis was used to detect the diurnal cycle in the observed patterns of pollutants across Delhi. The results of our study indicated a consistently higher level of concentrations of all the pollutants at two of the stations, IGI Airport and Civil Lines, while lower concentration levels were observed in the mixed use residential areas of Shadipur and NSIT Dwarka. A clockwise gradual progression in the time of maximum from east to west was observed in the case of SO2 during each season. The time of maximum for O3 for each season was in the early evening hours, 1800 local standard time (LST). Moreover, there were little spatial variations in the peak time of occurrence of NO2 and O3 at the seasonal scale.

Reconstruction of nonstationary disordered materials and media: Watershed transform and cross-correlation function.

Nonstationary disordered materials and media, those for which the probability distribution function of any property varies spatially when shifted in space, are abundant and encountered in astrophysics, oceanography, air pollution patterns, large-scale porous media, biological tissues and organs, and composite materials. Their reconstruction and modeling is a notoriously difficult and largely unsolved problem. We propose a method for reconstructing a broad class of such media based on partitioning them into locally stationary zones. Two methods are used for the partitioning. One is based on the Shannon entropy, while the second method utilizes a watershed transform. The locally stationary zones are then reconstructed based on a cross-correlation function and one-dimensional raster path that we recently introduced [P. Tahmasebi and M. Sahimi, Phys. Rev. Lett. 110, 078002 (2013)], with overlaps between the zones to ensure seamless transition from one zone to another. A large number of examples, including porous media, ecological systems, disordered materials, and biological tissues and organs, are reconstructed and analyzed to demonstrate the accuracy of the method.

Public-health impact of outdoor air pollution for 2(nd) air pollution management policy in Seoul metropolitan area, Korea.

ObjectivesAir pollution contributes to mortality and morbidity. We estimated the impact of outdoor air pollution on public health in Seoul metropolitan area, Korea. Attributable cases of morbidity and mortality were estimated.MethodsEpidemiology-based exposure-response functions for a 10 μg/m3 increase in particulate matter (PM2.5 and PM10) were used to quantify the effects of air pollution. Cases attributable to air pollution were estimated for mortality (adults ≥ 30 years), respiratory and cardiovascular hospital admissions (all ages), chronic bronchitis (all ages), and acute bronchitis episodes (≤18 years). Environmental exposure (PM2.5 and PM10) was modeled for each 3 km × 3 km.ResultsIn 2010, air pollution caused 15.9% of total mortality or approximately 15,346 attributable cases per year. Particulate air pollution also accounted for: 12,511 hospitalized cases of respiratory disease; 20,490 new cases of chronic bronchitis (adults); 278,346 episodes of acute bronchitis (children). After performing the 2nd Seoul metropolitan air pollution management plan, the reducible death number associated with air pollution is 14,915 cases per year in 2024. We can reduce 57.9% of death associated with air pollution.ConclusionThis assessment estimates the public-health impacts of current patterns of air pollution. Although individual health risks of air pollution are relatively small, the public-health consequences are remarkable. Particulate air pollution remains a key target for public-health action in the Seoul metropolitan area. Our results, which have also been used for economic valuation, should guide decisions on the assessment of environmental health-policy options.

An assessment of the potential for co-exposure to allergenic pollen and air pollution in Copenhagen, Denmark

Co-exposure to air pollutants and pollen allergens can aggravate the allergic reaction and reduce the threshold at which susceptible individuals are affected. Here we assessed which air pollutants may be of particular relevance when investigating co-exposure with pollen. We examined the yearly variation and diurnal patterns of pollen and air pollution on days with peak pollen concentrations and non-peak days separately. The analysis was performed for measurements of grass and birch pollen, sulfur dioxide, ozone, nitrogen dioxide and particulate matter. Results indicated that high ozone concentrations coincide both seasonally and diurnally with high pollen concentrations, and that ozone concentrations were higher on peak pollen days, potentially leading to clinically relevant simultaneous co-exposure. For nitrogen dioxide and sulfur dioxide no periods with peaks simultaneously with peaks in pollen loads was identified, and concentrations were below potential thresholds for adjuvant effects to the allergic reaction. For particulate matter no simultaneous peaks in diurnal or seasonal concentrations were identified, however concentrations were higher on peak pollen days compared with non-peak days. When considering co-exposure effects from pollen and pollutants, ozone appears to be the most relevant pollutant to further examine for effects of simultaneous co-exposures.

Fine-scale estimation of carbon monoxide and fine particulate matter concentrations in proximity to a road intersection by using wavelet neural network with genetic algorithm

At road intersections, vehicles frequently stop with idling engines during the red-light period and speed up rapidly in the green-light period, which generates higher velocity fluctuation and thus higher emission rates. Additionally, the frequent changes of wind direction further add the highly variable dispersion of pollutants at the street scale. It is, therefore, very difficult to estimate the distribution of pollutant concentrations using conventional deterministic causal models.For this reason, a hybrid model combining wavelet neural network and genetic algorithm (GA–WNN) is proposed for predicting 5-min series of carbon monoxide (CO) and fine particulate matter (PM2.5) concentrations in proximity to an intersection. The proposed model is examined based on the measured data under two situations. As the measured pollutant concentrations are found to be dependent on the distance to the intersection, the model is evaluated in three locations respectively, i.e. 110 m, 330 m and 500 m. Due to the different variation of pollutant concentrations on varied time, the model is also evaluated in peak and off-peak traffic time periods separately. Additionally, the proposed model, together with the back-propagation neural network (BPNN), is examined with the measured data in these situations. The proposed model is found to perform better in predictability and precision for both CO and PM2.5 than BPNN does, implying that the hybrid model can be an effective tool to improve the accuracy of estimating pollutants' distribution pattern at intersections. The outputs of these findings demonstrate the potential of the proposed model to be applicable to forecast the distribution pattern of air pollution in real-time in proximity to road intersection.

Particle size distribution and air pollution patterns in three urban environments in Xi'an, China.

Three urban environments, office, apartment and restaurant, were selected to investigate the indoor and outdoor air quality as an inter-comparison in which CO2, particulate matter (PM) concentration and particle size ranging were concerned. In this investigation, CO2 level in the apartment (623 ppm) was the highest among the indoor environments and indoor levels were always higher than outdoor levels. The PM10 (333 µg/m(3)), PM2.5 (213 µg/m(3)), PM1 (148 µg/m(3)) concentrations in the office were 10-50% higher than in the restaurant and apartment, and the three indoor PM10 levels all exceeded the China standard of 150 µg/m(3). Particles ranging from 0.3 to 0.4 µm, 0.4 to 0.5 µm and 0.5 to 0.65 µm make largest contribution to particle mass in indoor air, and fine particles number concentrations were much higher than outdoor levels. Outdoor air pollution is mainly affected by heavy traffic, while indoor air pollution has various sources. Particularly, office environment was mainly affected by outdoor sources like soil dust and traffic emission; apartment particles were mainly caused by human activities; restaurant indoor air quality was affected by multiple sources among which cooking-generated fine particles and the human steam are main factors.

Potential Impact of Air Pollution on Multiple Sclerosis in Tehran, Iran

Background: Multiple sclerosis (MS) incidence has dramatically increased in Tehran, Iran. The health impact of air pollution in Tehran underscores the attention to a possible association to this environmental risk factor. In this study, the authors aimed to analyze the spatial distribution of prevalent MS cases and their association with the spatial patterns of air pollution. Methods: Patient records meeting McDonald's criteria for definite MS diagnosis with disease onset during 2003-2013 were obtained. Next, the location of 2,188 patients was successfully geo-referenced within Tehran metropolis by geographic information system (GIS) bureau of Iran's post office based on their phone numbers. A cluster analysis was performed using the average nearest neighbor index (ANNI) and quadrat analysis. The long-term exposures of MS patients to particulate matter (PM₁₀), sulfur dioxide (SO₂), nitrogen oxide (NO), nitrogen dioxide (NO₂), and nitrogen oxides (NOx) were estimated using the previously developed land use regression models. Results: Prevalent MS cases had a clustered pattern in Tehran. A significant difference in exposure to PM₁₀, SO₂, NO₂, and NOx (p < 0.001) was observed in MS cases compared with controls. Conclusion: This study revealed the potential role of long-term exposure to air pollutants as an environmental risk factor in MS.

The Impact of Green Space Changes on Air Pollution and Microclimates: A Case Study of the Taipei Metropolitan Area

In order to achieve a sustainable urban environment, the increase of green space areas is commonly used as a planning tool and adaptation strategy to combat environmental impacts resulting from global climate change and urbanization. Therefore, it is important to understand the change of green space areas and the derived impacts from the change. This research firstly applied space analysis and landscape ecology metrics to analyze the structure change of the pattern of green space area within the Taipei Metropolitan Area. Then, partial least squares were used to identify the consequences on microclimate and air pollution pattern caused by the changing pattern of green space areas within the districts of the Taipei Metropolitan Area. According to the analytical results, the green space area within Taipei Metropolitan Areas has decreased 1.19% from 1995 to 2007, but 93.19% of the green space areas have been kept for their original purposes. Next, from the landscape ecology metrics analysis, in suburban areas the linkages, pattern parameters, and space aggregation are all improving, and the fragmentation measure is also decreasing, but shape is becoming more complex. However, due to intensive land development in the city core, the pattern has becomes severely fragmented and decentralized causing the measures of the linkages and pattern parameters to decrease. The results from structural equation modeling indicate that the changing pattern of green space areas has great influences on air pollution and microclimate patterns. For instance, less air pollution, smaller rainfall patterns and cooler temperatures are associated with improvement in space aggregation, increasing the larger sized green space patch.

Air Pollution and Mortality Patterns in University’s Professors at Guadalajara’s Metropolitan Area

Air Pollution and Mortality Patterns in University’s Professors at Guadalajara’s Metropolitan Area

Spatial and temporal patterns of air pollutants in rural and urban areas of India

In this study, we analysed spatial and temporal patterns of Suspended Particulate Matter (SPM) concentrations across India. We have also assessed MODIS-derived aerosol optical depth (AOD) variations to characterize the air quality and relate it to SPM, NO2 and SO2 in different areas. In addition, the pollutant concentrations have been mapped using geospatial techniques. The results indicated significant differences in air pollutant levels across rural and urban areas. In general, districts of central and northern India had relatively higher SPM concentrations compared to southern India. Out of the top ten SPM polluted districts in India, nine were located in the state of Uttar Pradesh (UP). We observed significant correlations between the SPM and AOD at different sites. Although spatial and temporal patterns of NO2 and SO2 matched AOD patterns, the correlation strength (r2) varied based on location. The causes and implications of these findings are presented.

Asthma and asthma related symptoms in 23,326 Chinese children in relation to indoor and outdoor environmental factors: The Seven Northeastern Cities (SNEC) Study

BackgroundBoth the levels and patterns of outdoor and indoor air pollutants have changed dramatically during the last decade in China. However, few studies have evaluated the effects of the present air pollution on the health of Chinese children. This study examines the association between outdoor and indoor air pollution and respiratory diseases among children living in Liaoning, a heavy industrial province of China. MethodsA cross-sectional study of 23,326 Chinese children aged 6 to 13years was conducted in 25 districts of 7 cities in Northeast China during 2009. Three-year (2006–2008) average concentrations of particles with an aerodynamic diameter of ≤10μm (PM10), sulfur dioxide (SO2), nitrogen dioxides (NO2), and ozone (O3) were calculated from monitoring stations in each of the 25 districts. We used two-level logistic regression models to examine the effects of yearly variations in exposure to each pollutant, controlling for important covariates. ResultsThe prevalence of respiratory symptoms was higher for those dwelling close to a busy road, those living near smokestacks or factories, those living with smokers, those living in one-story houses typically with small yards, and those with home renovation, bedroom carpet or pets. Ventilation device use was associated with decreased odds of asthma in children. The adjusted odds ratio for diagnosed-asthma was 1.34 (95% confidence interval [CI], 1.24–1.45) per 31μg/m3 increase in PM10, 1.23 (95%CI, 1.14–1.32) per 21μg/m3 increase in SO2, 1.25 (95%CI, 1.16–1.36) per 10μg/m3 increase in NO2, and 1.31 (95%CI, 1.21–1.41) per 23μg/m3 increase in O3, respectively. ConclusionOutdoor and indoor air pollution was associated with an increased likelihood of respiratory morbidity among Chinese children.