Ozone Air Pollution Research Articles

A nonhomogeneous Poisson process geostatistical model

This paper introduces a new geostatistical model for counting data under a space-time approach using nonhomogeneous Poisson processes, where the random intensity process has an additive formulation with two components: a Gaussian spatial component and a component accounting for the temporal effect. Inferences of interest for the proposed model are obtained under the Bayesian paradigm. To illustrate the usefulness of the proposed model, we first develop a simulation study to test the efficacy of the Markov Chain Monte Carlo (MCMC) method to generate samples for the joint posterior distribution of the model’s parameters. This study shows that the convergence of the MCMC algorithm used to simulate samples for the joint posterior distribution of interest is easily obtained for different scenarios. As a second illustration, the proposed model is applied to a real data set related to ozone air pollution collected in 22 monitoring stations in Mexico City in the 2010 year. The proposed geostatistical model has good performance in the data analysis, in terms of fit to the data and in the identification of the regions with the highest pollution levels, that is, the southwest, the central and the northwest regions of Mexico City.

Ozone phytotoxicity in the Western Carpathian Mountains in Slovakia

Abstract In this work, the response of temperate coniferous forests to ozone air pollution (O3) in the mountain environment of the High Tatra Mts. (Western Carpathians) was analyzed. The modelling of stomatal O3 flux is a complex method for the estimation of phytotoxicity of O3 pollution to forest vegetation. Stomatal flux-based critical levels (CLef) for effects of O3 on radial growth take into account the varying influences of O3 concentration, meteorological variables, soil properties, and phenology. The application of the model DO3SE (Deposition of Ozone for Stomatal Exchange) at five experimental plots with altitudes varying from 810 to 1,778 m a.s.l. along vertical and spatial profile in the High Tatra Mts. revealed the high phytotoxic potential of O3 on spruce forests during the growing season 2014. The accumulated stomatal O3 flux above a threshold of Y (1 nmol m−2 s−1), i.e. POD1 (Phytotoxic Ozone Dose) ranged from 13.6 mmol m−2 at the Kolové pleso site (1,570 m a.s.l.) to 16.2 mmol m−2 at Skalnaté Pleso site (1,778 m a.s.l.). CLef for POD1 (8 mmol m−2) recommended for the protection of spruce forests were exceeded at all experimental plots from early July. Similarly, AOT40 index suggests vulnerability of mountain forests to O3 pollution. AOT40 values increased with altitude and reached values varying from 6.2 ppm h in Stará Lesná (810 m a.s.l.) to 10.7 ppm h at Skalnaté Pleso close to the timber line (1,778 m a.s.l.). Concentration-based critical level (CLec) of 5,000 ppb h was exceeded from June to August and was different for each experimental site.

The urban forest and ecosystem services

The urban forest and ecosystem services

Modeled response of ozone to electricity generation emissions in the northeastern United States using three sensitivity techniques

ABSTRACTElectrical generation units (EGUs) are important sources of nitrogen oxides (NOx) that contribute to ozone air pollution. A dynamic management system can anticipate high ozone and dispatch EGU generation on a daily basis to attempt to avoid violations, temporarily scaling back or shutting down EGUs that most influence the high ozone while compensating for that generation elsewhere. Here we investigate the contributions of NOx from individual EGUs to high daily ozone, with the goal of informing the design of a dynamic management system. In particular, we illustrate the use of three sensitivity techniques in air quality models—brute force, decoupled direct method (DDM), and higher-order DDM—to quantify the sensitivity of high ozone to NOx emissions from 80 individual EGUs. We model two episodes with high ozone in the region around Pittsburgh, PA, on August 4 and 13, 2005, showing that the contribution of 80 EGUs to 8-hr daily maximum ozone ranges from 1 to >5 ppb at particular locations. At these locations and on the two high ozone days, shutting down power plants roughly 1.5 days before the 8-hr ozone violation causes greater ozone reductions than 1 full day before; however, the benefits of shutting down roughly 2 days before the high ozone are modest compared with 1.5 days. Using DDM, we find that six EGUs are responsible for >65% of the total EGU ozone contribution at locations of interest; in some locations, a single EGU is responsible for most of the contribution. Considering ozone sensitivities for all 80 EGUs, DDM performs well compared with a brute-force simulation with a small normalized mean bias (–0.20), while this bias is reduced when using the higher-order DDM (–0.10).Implications: Dynamic management of electrical generation has the potential to meet daily ozone air quality standards at low cost. We show that dynamic management can be effective at reducing ozone, as EGU contributions are important and as the number of EGUs that contribute to high ozone in a given location is small (<6). For two high ozone days and seven geographic regions, EGUs would best be shut down or their production scaled back roughly 1.5 days before the forecasted exceedance. Including online sensitivity techniques in an air quality forecasting model can provide timely and useful information on which EGUs would be most beneficial to shut down or scale back temporarily.

The association between lung cancer incidence and ambient air pollution in China: A spatiotemporal analysis

BackgroundChina is experiencing more and more days of serious air pollution recently, and has the highest lung cancer burden in the world. ObjectivesTo examine the associations between lung cancer incidence and fine particles (PM2.5) and ozone in China. MethodsWe used 75 communities’ data of lung cancer incidence from the National Cancer Registration of China from 1990 to 2009. The annual concentrations of fine particles (PM2.5) and ozone at 0.1°×0.1° spatial resolution were generated by combing remote sensing, global chemical transport models, and improvements in coverage of surface measurements. A spatial age-period-cohort model was used to examine the relative risks of lung cancer incidence associated with the air pollutants, after adjusting for impacts of age, period, and birth cohort, sex, and community type (rural and urban) as well as the spatial variation on lung cancer incidence. ResultsThe relative risks of lung cancer incidence related to a 10µg/m3 increase in 2-year average PM2.5 were 1.055 (95% confidence interval (CI): 1.038, 1.072) for men, 1.149 (1.120, 1.178) for women, 1.060 (1.044, 1.075) for an urban communities, 1.037 (0.998, 1.078) for a rural population, 1.074 (1.052, 1.096) for people aged 30–65 years, and 1.111 (1.077, 1.146) for those aged over 75 years. Ozone also had a significant association with lung cancer incidence. ConclusionsThe increased risks of lung cancer incidence were associated with PM2.5 and ozone air pollution. Control measures to reduce air pollution would likely lower the future incidence of lung cancer.

Short-term exposure to ambient ozone and stroke hospital admission: A case-crossover analysis.

We evaluated the association between short-term exposure to ambient ozone air pollution and stroke hospital admissions among adult residents of South Carolina (SC). Data on all incident stroke hospitalizations from 2002 to 2006 were obtained from the SC Office of Research and Statistics. Ozone exposure data were obtained from the US Environmental Protection Agency's Hierarchical Bayesian Model. A semi-symmetric bidirectional case-crossover design was used to examine the association between ozone exposure on lag days 0-2 (0 to 2 days before admission) and stroke hospitalization. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). No significant associations were observed between short-term ozone exposure and hospitalization for all stroke (e.g., lag day 0: OR=0.98; 95% CI=0.96, 1.00) or ischemic stroke (lag day 0: OR=0.98; 95% CI=0.96, 1.01). Risk of hospitalization for hemorrhagic stroke appeared to be higher among African Americans than European Americans; however, the majority of these associations did not reach statistical significance. Among adults in SC from 2002 to 2006, there was no evidence of an association between ozone exposure and risk of hospitalization for all stroke or ischemic stroke; however, African Americans may have an increased risk of hemorrhagic stroke.

Environmental Pollutant Ozone Causes Damage to Lung Surfactant Protein B (SP-B).

Lung surfactant protein B (SP-B) is an essential protein found in the surfactant fluid at the air–water interface of the lung. Exposure to the air pollutant ozone could potentially damage SP-B and lead to respiratory distress. We have studied two peptides, one consisting of the N-terminus of SP-B [SP-B(1–25)] and the other a construct of the N- and C-termini of SP-B [SP-B(1–25,63–78)], called SMB. Exposure to dilute levels of ozone (∼2 ppm) of monolayers of each peptide at the air–water interface leads to a rapid reaction, which is evident from an increase in the surface tension. Fluorescence experiments revealed that this increase in surface tension is accompanied by a loss of fluorescence from the tryptophan residue at the interface. Neutron and X-ray reflectivity experiments show that, in contrast to suggestions in the literature, the peptides are not solubilized upon oxidation but rather remain at the interface with little change in their hydration. Analysis of the product material reveals that no cleavage of the peptides occurs, but a more hydrophobic product is slowly formed together with an increased level of oligomerization. We attributed this to partial unfolding of the peptides. Experiments conducted in the presence of phospholipids reveal that the presence of the lipids does not prevent oxidation of the peptides. Our results strongly suggest that exposure to low levels of ozone gas will damage SP-B, leading to a change in its structure. The implication is that the oxidized protein will be impaired in its ability to interact at the air–water interface with negatively charged phosphoglycerol lipids, thus compromising what is thought to be its main biological function.

Is the ozone climate penalty robust in Europe?

Ozone air pollution is identified as one of the main threats bearing upon human health and ecosystems, with 25 000 deaths in 2005 attributed to surface ozone in Europe (IIASA 2013 TSAP Report #10). In addition, there is a concern that climate change could negate ozone pollution mitigation strategies, making them insufficient over the long run and jeopardising chances to meet the long term objective set by the European Union Directive of 2008 (Directive 2008/50/EC of the European Parliament and of the Council of 21 May 2008) (60 ppbv, daily maximum). This effect has been termed the ozone climate penalty. One way of assessing this climate penalty is by driving chemistry-transport models with future climate projections while holding the ozone precursor emissions constant (although the climate penalty may also be influenced by changes in emission of precursors). Here we present an analysis of the robustness of the climate penalty in Europe across time periods and scenarios by analysing the databases underlying 11 articles published on the topic since 2007, i.e. a total of 25 model projections. This substantial body of literature has never been explored to assess the uncertainty and robustness of the climate ozone penalty because of the use of different scenarios, time periods and ozone metrics. Despite the variability of model design and setup in this database of 25 model projection, the present meta-analysis demonstrates the significance and robustness of the impact of climate change on European surface ozone with a latitudinal gradient from a penalty bearing upon large parts of continental Europe and a benefit over the North Atlantic region of the domain. Future climate scenarios present a penalty for summertime (JJA) surface ozone by the end of the century (2071–2100) of at most 5 ppbv. Over European land surfaces, the 95% confidence interval of JJA ozone change is [0.44; 0.64] and [0.99; 1.50] ppbv for the 2041–2070 and 2071–2100 time windows, respectively.

Bladder Cancer Mortality in the United States: A Geographic and Temporal Analysis of Socioeconomic and Environmental Factors

We assessed the association of temporal, socioeconomic and environmental factors with bladder cancer mortality in the United States. Our hypothesis was that bladder cancer mortality is associated with distinct environmental and socioeconomic factors with effects varying by region, race and gender. NCI (National Cancer Institute) age adjusted, county level bladder cancer mortality data from 1950 to 2007 were analyzed to identify clusters of increased bladder cancer death using the Getis-Ord Gi* statistic. Socioeconomic, clinical and environmental data were assessed using geographically weighted spatial regression analysis adjusting for spatial autocorrelation. County level socioeconomic, clinical and environmental data were obtained from national databases, including the United States Census, CDC (Centers for Disease Control and Prevention), NCHS (National Center for Health Statistics) and County Health Rankings. Bladder cancer mortality hot spots and risk factors for bladder cancer death differed significantly by gender, race and geographic region. From 1996 to 2007 smoking, unemployment, physically unhealthy days, air pollution ozone days, percent of houses with well water, employment in the mining industry and urban residences were associated with increased rates of bladder cancer mortality (p <0.05). Model fit was significantly improved in hot spots compared to all American counties (R(2) = 0.20 vs 0.05). Environmental and socioeconomic factors affect bladder cancer mortality and effects appear to vary by gender and race. Additionally there were temporal trends of bladder cancer hot spots which, when persistent, should be the focus of individual level studies of occupational and environmental factors.

Spatial and temporal variability of ozone sensitivity over China observed from the Ozone Monitoring Instrument

AbstractSurface ozone (O3) air pollution in populated regions has been attributed to emissions of nitrogen oxides (NO + NO2 = NOx) and reactive volatile organic compounds (VOCs). These constituents react with hydrogen oxide radicals (OH + HO2 = HOx) in the presence of sunlight and heat to produce O3. The question of whether to reduce NOx emissions, VOC emissions, or both is complicated by spatially and temporally heterogeneous ozone‐NOx‐VOC sensitivity. This study characterizes spatial and temporal variations in O3 sensitivity by analyzing the ratio of formaldehyde (HCHO, a marker of VOCs) to nitrogen dioxide (NO2), a metric known as the formaldehyde nitrogen ratio (FNR). Level 3 gridded retrievals from the Ozone Monitoring Instrument (OMI) aboard the NASA Aura satellite were used to calculate FNR, with our analysis focusing on China. Based on previous studies, we take FNR &lt; 1.0 as indicating VOC‐limited regimes, FNR &gt; 2.0 as indicating NOx‐limited regime, and FNR between 1.0 and 2.0 as indicating transitional regime (where either NOx reductions or VOC reductions would be expected to reduce O3). We find that the transitional regime is widespread over the North China Plain (NCP), the Yangtze River Delta, and the Pearl River Delta during the ozone season (defined as having near‐surface air temperatures &gt;20°C at the early afternoon OMI overpass time). Outside of these regions, the NOx‐limited regime is dominant. Because HCHO and NO2 have distinct seasonal patterns, FNR also has a pronounced seasonality, consistent with the seasonal cycle of surface O3. Examining trends from 2005 to 2013 indicates rapid growth in NO2, especially over less‐developed areas where O3 photochemistry is NOx limited. Over this time period, HCHO decreased in southern China, where VOC emissions are dominated by biogenic sources, but increased slightly over the NCP, where VOC emissions are dominated by anthropogenic sources. A linear regression approach suggests that most of China (70% of grid cells) will be characterized by a transitional regime during the O3 season by 2030. However, in megacities such as Guangzhou, Shanghai, and Beijing, NO2 has decreased such that the chemical regime has shifted from VOC limited in 2005 to transitional in 2013.

Effect of naturally occurring ozone air pollution episodes on pulmonary oxidative stress and inflammation.

This study aimed to determine if naturally occurring episodes of ozone air pollution in the Salt Lake Valley in Utah, USA, during the summer are associated with increased pulmonary inflammation and oxidative stress, increased respiratory symptoms, and decreased lung function in individuals with chronic obstructive pulmonary disease (COPD) compared to controls. We measured biomarkers (nitrite/nitrate (NOx), 8-isoprostane) in exhaled breath condensate (EBC), spirometry, and respiratory symptoms in 11 former smokers with moderate-to-severe COPD and nine former smokers without airflow obstruction during periods of low and high ozone air pollution. High ozone levels were associated with increased NOx in EBC in both COPD (8.7 (±8.5) vs. 28.6 (±17.6) μmol/L on clean air vs. pollution days, respectively, p < 0.01) and control participants (7.6 (±16.5) vs. 28.5 (±15.6) μmol/L on clean air vs. pollution days, respectively, p = 0.02). There was no difference in pollution effect between COPD and control groups, and no difference in EBC 8-isoprostane, pulmonary function, or respiratory symptoms between clean air and pollution days in either group. Former smokers both with and without airflow obstruction developed airway oxidative stress and inflammation in association with ozone air pollution episodes.

Epithelial IL-33 and TSLP Elicit Innate Lymphoid Cell Responses to Mediate Ozone-Induced Airway Inflammation and Hyperresponsiveness

Exposure to the common air pollutant ozone is a global respiratory health problem. The mechanisms by which ozone impairs lung function and exacerbates respiratory diseases remain unclear. Pulmonary group-2 innate lymphoid cells (ILC2) are a prominent source of IL-5 and IL13 in responses to epithelium-derived cytokines IL-33 and TSLP.

Mitigation of Pollution-induced Deterioration of Digital Prints through the Use of Enclosures

The potential for common enclosures to reduce or prevent pollutant-induced deterioration of inkjet materials was investigated, with the specific research question being: Can any of the various commonly-used enclosure designs and materials (envelopes/boxes, paper/plastics) be used to effectively reduce or prevent the damage to digital prints caused by Ozone or Nitrogen Dioxide air pollution? The results indicate clear guidelines how to best proceed to mitigate pollutant gas damage. Polyester sleeves show by far the greatest potential for both pollutants over all tests conducted, which indicates this benefit may extend to the parts-per-billion range. Increasing ppm values and equally reducing exposure times to create the same ppm-days exposure did not always result in the same color change to the prints inside or outside enclosures. This importantly indicates extended time periods and lower concentrations could mean an enclosure's effectiveness in preventing damage from pollution could be in fact much lower than that observed in highly accelerated testing (as seen in this work and elsewhere). This raises questions regarding the suitability of such techniques to appraise the efficacy of enclosures employed to deter pollution damage caused over longer periods (decades) at real world environmental pollution levels.

Long Term Chronic Exposure to Ozone Air Pollution and Biomarkers of Cardiovascular Diseases in Adult National Health and Nutrition Examination Survey Participants

Long Term Chronic Exposure to Ozone Air Pollution and Biomarkers of Cardiovascular Diseases in Adult National Health and Nutrition Examination Survey ParticipantsAbstract Number:2747 Arvind Dabass*, Evelyn Talbott, LuAnn Brink, Judy Rager, Fernando Holguin Arvind Dabass* University of Pittsburgh, United States, E-mail Address: [email protected] Search for more papers by this author , Evelyn Talbott University of Pittsburgh, United States, E-mail Address: [email protected] Search for more papers by this author , LuAnn Brink University of Pittsburgh, United States, E-mail Address: [email protected] Search for more papers by this author , Judy Rager University of Pittsburgh, United States, E-mail Address: [email protected] Search for more papers by this author , and Fernando Holguin University of Pittsburgh, United States, E-mail Address: [email protected] Search for more papers by this author AbstractBackground and Aim: Exposure to ozone (O3) has been associated with increased cardiovascular morbidity and mortality, a hypothesized biological mechanism being systemic inflammation. The goal of this study was to examine the association of long term chronic exposure to O3 air pollution with systemic inflammation in adult National Health and Nutrition Examination Survey (NHANES) participants.Methods: 4 cycles (2001-08) of NHANES data were merged with air pollution data obtained from United States Environmental Protection Agency’s modeled fused air quality surface data. Data for analyzing C-reactive protein (CRP) and White Blood Cells (WBC), markers of systemic inflammation, were available for 17071 and 17171 participants respectively. Multiple linear regression models were used for analysis after adjusting for age, gender, race, body mass index (BMI), smoking status, annual average particulate matter (PM2.5). SAS Survey procedure i.e. SURVEYREG was used to account for complex survey design of NHANES. Stratified analyses were conducted for gender, race, BMI and smoking status.Results: Mean (SE) annual average O3 level for the study period was 39.9 (0.30) parts per billion (ppb). Mean (SE) for CRP and WBC were 0.41(0.01) mg/dl and 7.28 *103 (0.03) cells/mm3 respectively. Annual average O3 was significantly positively associated with CRP and WBC. For every 10 ppb increase in annual average O3 level, CRP increased by 6.4 % (95% CI: 1.06-12.03) and WBC by 0.20 *103 cells/mm3 (95% CI: 0.08-0.31). In stratified analyses for CRP, associations were significantly positive in males, current smokers, non-obese and non-Hispanic Whites. In stratified analyses for WBC, associations were significantly positive in all the subgroups except current smokers, non-Hispanic Blacks and Mexican Americans.Conclusion: Long term chronic exposure to O3 air pollution may increase CRP and WBC, thus, partly explaining link between air pollution and cardiovascular diseases.

Increasing external effects negate local efforts to control ozone air pollution: a case study of Hong Kong and implications for other Chinese cities.

It is challenging to reduce ground-level ozone (O3) pollution at a given locale, due in part to the contributions of both local and distant sources. We present direct evidence that the increasing regional effects have negated local control efforts for O3 pollution in Hong Kong over the past decade, by analyzing the daily maximum 8 h average O3 and Ox (=O3+NO2) concentrations observed during the high O3 season (September-November) at Air Quality Monitoring Stations. The locally produced Ox showed a statistically significant decreasing trend over 2002-2013 in Hong Kong. Analysis by an observation-based model confirms this decline in in situ Ox production, which is attributable to a reduction in aromatic hydrocarbons. However, the regional background Ox transported into Hong Kong has increased more significantly during the same period, reflecting contributions from southern/eastern China. The combined result is a rise in O3 and a nondecrease in Ox. This study highlights the urgent need for close cross-boundary cooperation to mitigate the O3 problem in Hong Kong. China's air pollution control policy applies primarily to its large cities, with little attention to developing areas elsewhere. The experience of Hong Kong suggests that this control policy does not effectively address secondary pollution, and that a coordinated multiregional program is required.

Pixel classification methods for identifying and quantifying leaf surface injury from digital images

Plants exposed to stress due to pollution, disease or nutrient deficiency often develop visible symptoms on leaves such as spots, colour changes and necrotic regions. Early symptom detection is important for precision agriculture, environmental monitoring using bio-indicators and quality assessment of leafy vegetables. Leaf injury is usually assessed by visual inspection, which is labour-intensive and to a considerable extent subjective. In this study, methods for classifying individual pixels as healthy or injured from images of clover leaves exposed to the air pollutant ozone were tested and compared. RGB images of the leaves were acquired under controlled conditions in a laboratory using a standard digital SLR camera. Different feature vectors were extracted from the images by including different colour and texture (spatial) information. Four approaches to classification were evaluated: (1) Fit to a Pattern Multivariate Image Analysis (FPM) combined with T2 statistics (FPM-T2) or (2) Residual Sum of Squares statistics (FPM-RSS), (3) linear discriminant analysis (LDA) and (4) K-means clustering. The predicted leaf pixel classifications were trained from and compared to manually segmented images to evaluate classification performance. The LDA classifier outperformed the three other approaches in pixel identification with significantly higher accuracy, precision, true positive rate and F-score and significantly lower false positive rate and computation time. A feature vector of single pixel colour channel intensities was sufficient for capturing the information relevant for pixel identification. Including neighbourhood pixel information in the feature vector did not improve performance, but significantly increased the computation time. The LDA classifier was robust with 95% mean accuracy, 83% mean true positive rate and 2% mean false positive rate, indicating that it has potential for real-time applications.

Short-Term Exposure to Ambient Ozone and Acute Stroke Risk: A Case-Crossover Analysis

Short-Term Exposure to Ambient Ozone and Acute Stroke Risk: A Case-Crossover Analysis

Threat to future global food security from climate change and ozone air pollution

This study shows that climate change has the potential to substantially increase undernourishment rates and threaten food security in developing countries through crop damage, but that ozone regulation can significantly offset climate impacts, depending on the scenario. The findings should help policymakers devise optimal strategies for food production under global climate change.

A Health Risk Assessment of Carbonyl-containing Volatile Organic Compounds in the Atmosphere of Chinese Megacities

Carbonyl-containing volatile organic compounds (cVOCs) are important precursors of atmospheric photochemical reactions in the formation of ozone, smog and other air pollutants. China’s megacities are economically developed and densely populated metropolitan areas, usually with a population over ten million; they drive the rapid growth of surrounding urban clusters. So far, 21 cVOCs have been detected in the atmosphere of these megacities. The average annual total concentration of cVOCs is 55.6 μg/m3, an alarmingly high level. Vehicle emissions, industrial discharges, excessive use of organic solvents and other factors have led to a situation where hazardous formaldehyde, acetaldehyde and acetone account for 62.4 percent of the total atmospheric concentration of cVOC in Chinese cities. In a quantitative evaluation using daily exposure levels, cancer risk and hazard quotient, we found that the excessive levels of atmospheric cVOCs in Beijing, Shanghai and Guangzhou pose serious health risks to their inhabitants. Air pollution persists, despite the brief improvements in air quality brought about by the air quality campaign undertaken during major international events like the 2008 Olympic Games, the 2010 Asian Games, and the 2010 World Expo. The health risks caused by atmospheric cVOCs in Chinese cities require close attention.

A new model to assess the environmental impact and sustainability of energy systems

This study develops a novel sustainability assessment methodology for energy systems using life-cycle emission factors and sustainability indicators. Here, the global warming and environmental impact dimensions of the sustainability assessment methodology are examined in detail. A comparative analysis shows that a wind-battery system produces fewer potential global warming, stratospheric ozone depletion, air pollution, and water pollution impacts compared to a gas-fired system. The wind-battery system generates 13% of the life-cycle GHG emissions and 22% of the life-cycle ozone-depleting substance emissions of a gas-fired power plant. Nitrous oxide contributes more than 90% of the stratospheric ozone depletion potential of gas-fired and wind-battery systems.