Short-term associations of ambient air pollution with hospital admissions for ischemic stroke in 97 Japanese cities.

The short-term association between ambient air pollution and hospital admissions for ischemic stroke is not fully understood. We examined the association between four regularly measured major ambient air pollutants, i.e., sulfur dioxide (SO2), nitrogen dioxide (NO2), photochemical oxidants (Ox), and particulate matter with aerodynamic diameters ≤ 2.5 µm (PM2.5), and hospital admissions for ischemic stroke by analyzing 3 years of nationwide claims data from 97 cities in Japan. We first estimated city-specific results by using generalized additive models with a quasi-Poisson regression, and we obtained the national average by combining city-specific results with the use of random-effect models. We identified a total of 335,248 hospital admissions for ischemic stroke during the 3-year period. Our analysis results demonstrated that interquartile range increases in the following four ambient air pollutants were significantly associated with hospital admissions for ischemic stroke on the same day: SO2 (1.05 ppb), 1.05% (95% CI: 0.59-1.50%); NO2 (6.40 ppb), 1.10% (95% CI: 0.61-1.59%); Ox (18.32 ppb), 1.43% (95% CI: 0.81-2.06%); and PM2.5 (7.86 µg/m3), 0.90% (95% CI: 0.35-1.45%). When the data were stratified by the hospital admittees' medication use, we observed stronger associations with SO2, NO2, and PM2.5 among the patients who were taking antihypertensive drugs and weaker associations with SO2, NO2, and Ox among those taking antiplatelet drugs. Short-term exposure to ambient air pollution was associated with increased hospital admissions for ischemic stroke, and medication use and season may modify the association.

[Establishment and International Harmonization of Photosafety Testing Strategy].

Considerable attention has been drawn to predict a photosafety hazard on new chemicals. A number of phototoxins tend to generate reactive oxygen species (ROS) via energy transfer mechanisms following UV/VIS excitation, including superoxide and singlet oxygen. Then, ROS assay has been designed to assess photoreactivity of pharmaceuticals, of which the principle is to monitor types I and II photochemical reactions of the test chemicals when exposed to simulated sunlight. This simple analytical test could be used to screen potential chemical scaffolds, leads, and candidate drugs to identify and/or select away from those having phototoxic potential. The validation study for the ROS assay has been being carried out by the Japan Pharmaceutical Manufacturers Association (JPMA), supervised by the Japanese Center for the Validation of Alternative Methods (JaCVAM). Although several false positives appeared, the ROS assay on 42 coded chemicals has provided no false negative predictions. The validation study tentatively indicates satisfactory outcomes in terms of transferability, intra- and inter-laboratory variability, and predictive capacity. Thus, a negative result in this ROS assay would indicate a very low probability of phototoxicity, whereas a positive result would be a flag for follow-up assessment. Upon international harmonization activities supported by several agencies and industrial groups, ROS assay was successfully adopted as International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) S10 guideline (2014) and Organisation for Economic Co-operation and Development (OECD) test guideline 495 (2019).

Assessing the effects of elevated ozone on physiology, growth, yield and quality of soybean in the past 40 years: A meta-analysis.

Soybean (Glycine max) production is seriously threatened by ground-level ozone (O3) pollution. The goal of our study is to summarize the impacts of O3 on physiology, growth, yield, and quality of soybean, as well as root parameters. We performed meta-analysis on the collated 48 peer-reviewed papers published between 1980 and 2019 to quantitatively summarize the response of soybean to elevated O3 concentrations ([O3]). Relative to charcoal-filtered air (CF), elevated [O3] significantly accelerated chlorophyll degradation, enhanced foliar injury, and inhibited growth of soybean, evidenced by great reductions in leaf area (-20.8%), biomass of leaves (-13.8%), shoot (-22.8%), and root (-16.9%). Shoot of soybean was more sensitive to O3 than root in case of biomass. Chronic ozone exposure of about 75.5 ppb posed pronounced decrease in seed yield of soybean (-28.3%). In addition, root environment in pot contributes to higher reduction in shoot biomass and yield of soybean. Negative linear relationships were observed between yield loss and intensity of O3 treatment, AOT40. The larger loss in seed yield was significantly associated with higher reduction in shoot biomass and other yield component. This meta-analysis demonstrates the effects of elevated O3 on soybean were pronounced, suggesting that O3 pollution is still a soaring threat to the productivity of soybean in regions with high ozone levels.

Air pollutant source characterization using the revised regional haze tracking metric and a photochemical grid model and implications for regional haze planning.

The 2017 revisions to the Regional Haze Rule clarify that visibility progress at Class I national parks and wilderness areas should be tracked on days with the highest anthropogenic contributions to haze (impairment). We compare the natural and anthropogenic contributions to haze in the western United States in 2011 estimated using the Environmental Protection Agency (EPA) recommended method and using model projections from the Comprehensive Air Quality Model with Extensions (CAMx) and the Particulate Source Apportionment Tool (PSAT). We do so because these two methods will be used by states to demonstrate visibility progress by 2028. If the two methods assume different natural and anthropogenic contributions, the projected benefits of reducing U.S. anthropogenic emissions will differ. The EPA method assumes that episodic elevated carbonaceous aerosols greater than an annual 95th percentile threshold are natural events. For western U.S. IMPROVE monitoring sites reviewed in this paper, CAMx-PSAT confirms these episodes are impacted by carbon from wildfire or prescribed fire events. The EPA method assumes that most of the ammonium sulfate is anthropogenic in origin. At most western sites CAMx-PSAT apportions more of the ammonium sulfate on the most impaired days to global boundary conditions and anthropogenic Canadian, Mexican, and offshore shipping emissions than to U.S. anthropogenic sources. For ammonium nitrate and coarse mass, CAMx-PSAT apportions greater contributions to U.S. anthropogenic sources than the EPA method assigns to total anthropogenic contributions. We conclude that for western IMPROVE sites, the EPA method is effective in selecting days that are likely to be impacted by anthropogenic emissions and that CAMx-PSAT is an effective approach to estimate U.S. source contributions. Improved inventories, particularly international and natural emissions, and further evaluation of global and regional model performance and PSAT attribution methods are recommended to increase confidence in modeled source characterization. Implications: The western states intend to use the CAMx model to project visibility progress by 2028. Modeled visibility response to changes in U.S. anthropogenic emissions may be less than estimated using the EPA assumptions based on total U.S. and international anthropogenic contributions to visibility impairment. Additional model improvements are needed to better account for contributions to haze from natural and international emissions in current and future modeling years. These improvements will allow more direct comparison of model and EPA estimates of natural and anthropogenic contributions to haze and future visibility progress.

Association of short-term ozone exposure with pulmonary function and respiratory symptoms in schoolchildren:A panel study in a western Japanese city.

The average annual ozone levels have been increasing in Japan, even though the high ozone levels have decreased in recent years. There is limited information on the relationship between ozone exposure, pulmonary function, and respiratory symptoms in schoolchildren in Japan. The aim of this study was to investigate the effects of short-term ozone exposure on pulmonary function and respiratory symptoms in Japanese schoolchildren. Afternoon peak expiratory flow (PEF) values and respiratory symptom scores were recorded daily in 276 schoolchildren from September to October 2016 and from January to February 2017. The association of daily ozone levels with PEF was assessed using a linear mixed model and that with respiratory symptoms was evaluated by generalized estimating equations logistic regression analysis. There was a significant association of daily ozone levels with PEF values. A 13.6-ppb increment in the interquartile range for ozone exposure was significantly associated with a decrease in PEF of -3.67 L/min (95% confidence interval -4.73, -2.61). However, increased ozone levels were not associated with an increased risk of respiratory symptoms. Our present findings suggest that more attention should be paid to the potential adverse effects of short-term ozone exposure on pulmonary function in schoolchildren. J. Med. Invest. 65:236-241, August, 2018.

Nitrogen dioxide exposure in school classrooms of inner-city children with asthma.

BACKGROUND: Ambient and home exposure to nitrogen dioxide (NO2) causes asthma symptoms and decreased lung function in children with asthma. Little is known about the health effects of school classroom pollution exposure. OBJECTIVE: We aimed to determine the effect of indoor classroom NO2 on lung function and symptoms in inner-city school children with asthma. METHODS: Children enrolled in the School Inner-City Asthma Study were followed for 1 academic year. Subjects performed spirometry and had fraction of exhaled nitric oxide values measured twice during the school year at school. Classroom NO2 was collected by means of passive sampling for 1-week periods twice per year, coinciding with lung function testing. Generalized estimating equation models assessed lung function and symptom relationships with the temporally nearest classroom NO2 level. RESULTS: The mean NO2 value was 11.1 ppb (range, 4.3-29.7 ppb). In total, exposure data were available for 296 subjects, 188 of whom had complete spirometric data. At greater than a threshold of 8 ppb of NO2 and after adjusting for race and season (spirometry standardized by age, height, and sex), NO2 levels were associated highly with airflow obstruction, such that each 10-ppb increase in NO2 level was associated with a 5% decrease in FEV1/forced vital capacity ratio (ß = -0.05; 95% CI, -0.08 to -0.02; P = .01). Percent predicted forced expiratory flow between the 25th and 75th percentile of forced vital capacity was also inversely associated with higher NO2 exposure (ß = -22.8; 95% CI, -36.0 to -9.7; P = .01). There was no significant association of NO2 levels with percent predicted FEV1, fraction of exhaled nitric oxide, or asthma symptoms. Additionally, there was no effect modification of atopy on lung function or symptom outcomes. CONCLUSION: In children with asthma, indoor classroom NO2 levels can be associated with increased airflow obstruction.

Health Effects of Air Pollution: A Historical Review and Present Status.

During the 1960s, the concentrations of air pollutants, particularly that of sulfur dioxide (SO2), were extremely high in many industrial cities in Japan, and the prevalence of bronchial asthma and chronic bronchitis increased among residents living in the cities. To evaluate the effects of air pollution on respiratory diseases, many epidemiological studies were conducted, and the findings played an important role in the regulatory control of air pollution. After 1970, the concentration of SO2 has decreased markedly, and its adverse health effects have been minimized. On the other hand, the increasing automobile traffic in Japan has caused considerable increases in concentrations of air pollutants, such as nitrogen oxides (NOx) and particulate matter (PM). The large-scale epidemiological studies conducted in Japan showed that traffic-related air pollution was associated with the development of asthma in school children and the persistence of asthmatic symptoms in preschool children. In recent years, however, the concentrations of NOx and PM have gradually decreased, since control measures based on the Automobile NOx/PM law were enforced in 2001. At present, the adverse health effects of airborne fine particulate matter (PM2.5) and photochemical oxidants have become a major concern. These air pollutants consist of not only emissions from primary sources but also secondary formations in air, and have spread worldwide. Both short- and long-term exposure to these air pollutants are reported to increase the risk of respiratory and cardiovascular diseases in the population. Therefore, global efforts are necessary to reduce the health risk of these air pollutants.

Heterogeneous reaction of peroxyacetyl nitrate (PAN) on soot.

The interaction between photochemical oxidants and aerosol particles has been examined in previous atmospheric pollution studies. The heterogeneous reaction can affect the concentration of gases and free radicals, as well as the morphology and properties of particles. In this report, the interaction between the photochemical oxidant peroxyacetyl nitrate (PAN) and soot particles was investigated using a flow tube system. We used real-time online monitoring equipment to track changes in PAN concentrations. Substances on the soot surface were detected using ion chromatography (IC), x-ray photoelectron spectroscopy (XPS), and other surface analysis methods. At 295 K, the upper and lower limits of the initial uptake coefficients were 1.28 × 10-5 and 9.16 × 10-9, respectively. The heterogeneous reaction of PAN on soot was a first-order reaction to PAN under both dry and wet conditions. The products formed on soot included CH3COO-, HCOO-, NO2-, and NO3-. With an increase in relative humidity, the production of all species decreased and the relative amounts changed.

Expected ozone benefits of reducing nitrogen oxide (NOx) emissions from coal-fired electricity generating units in the eastern United States.

On hot summer days in the eastern United States, electricity demand rises, mainly because of increased use of air conditioning. Power plants must provide this additional energy, emitting additional pollutants when meteorological conditions are primed for poor air quality. To evaluate the impact of summertime NOx emissions from coal-fired electricity generating units (EGUs) on surface ozone formation, we performed a series of sensitivity modeling forecast scenarios utilizing EPA 2018 version 6.0 emissions (2011 base year) and CMAQ v5.0.2. Coal-fired EGU NOx emissions were adjusted to match the lowest NOx rates observed during the ozone seasons (April 1-October 31) of 2005-2012 (Scenario A), where ozone decreased by 3-4 ppb in affected areas. When compared to the highest emissions rates during the same time period (Scenario B), ozone increased ∼4-7 ppb. NOx emission rates adjusted to match the observed rates from 2011 (Scenario C) increased ozone by ∼4-5 ppb. Finally in Scenario D, the impact of additional NOx reductions was determined by assuming installation of selective catalytic reduction (SCR) controls on all units lacking postcombustion controls; this decreased ozone by an additional 2-4 ppb relative to Scenario A. Following the announcement of a stricter 8-hour ozone standard, this analysis outlines a strategy that would help bring coastal areas in the mid-Atlantic region closer to attainment, and would also provide profound benefits for upwind states where most of the regional EGU NOx originates, even if additional capital investments are not made (Scenario A). IMPLICATIONS: With the 8-hr maximum ozone National Ambient Air Quality Standard (NAAQS) decreasing from 75 to 70 ppb, modeling results indicate that use of postcombustion controls on coal-fired power plants in 2018 could help keep regions in attainment. By operating already existing nitrogen oxide (NOx) removal devices to their full potential, ozone could be significantly curtailed, achieving ozone reductions by up to 5 ppb in areas around the source of emission and immediately downwind. Ozone improvements are also significant (1-2 ppb) for areas affected by cross-state transport, especially Mid-Atlantic coast regions that had struggled to meet the 75 ppb standard.

Outdoor and indoor ozone level--A potential impact on human health.

BACKGROUND/AIM: Air pollution outside and inside is still one of the most sensitive issues. The aim of this study was to assess the ozone level in ambient air and working premises in terms of its possible influence on human health. METHODS: The study was based on the results obtained in Lithuanian conditions. Continuous ozone measurement data from the rural monitoring station in Preila over the period 1995-2011 were analyzed. More than 180,000 hourly values were examined according to the requirements in the Directive 2008/50/EC. The World Health Organization (WHO) and European Union indicators the Sum of Ozone Means Over 35 ppb (SOMO 35), the maximum daily 8-hour mean concentration of ozone higher than 100 and 120 microg/m3 were estimated. Indoor ozone concentrations in copying and welding rooms were evaluated. The ozone concentration was measured with the ozone analyzer 0341M. RESULTS: The frequency distribution of ozone hourly concentrations at the Preila station showed that less than 1% of the data were higher than 120 microg/m3 and 6% of them higher than 100 microg/m3, that could have the adverse effect on human health, during 1995-2011. The investigations made in working premises showed that near a copying machine the ozone concentration can reach 330 +/- microg/m3, however in the room, i.e., 0.5 m from the machine, the average ozone concentration during automatic copying was 165 microg/m3 and during manual copying it was 50 microg/m3. Measurements in a welding room showed that the ozone concentration was in the range of 380-1850 microg/m3 at the distance of 25 cm from the electrode and at the distance of 1 m from the source the ozone concentration decreased 2.5 times. Conclusion. The danger of the ambient ozone level to human health practically was not observed in Lithuanian conditions. However, almost 6% of the data exceed the new WHO guideline of 100 microg/m3 during the measurement time. Indoor ozone during welding reached a higher level than during, copying that can cause human health problems.

Volatile trace compounds released from municipal solid waste at the transfer stage: Evaluation of environmental impacts and odour pollution.

Odour pollution caused by municipal solid waste is a public concern. This study quantitatively evaluated the concentration, environmental impacts, and olfaction of volatile trace compounds released from a waste transfer station. Seventy-six compounds were detected, and ethanol presented the highest releasing rate and ratio of 14.76 kg/d and 12.30 g/t of waste, respectively. Life cycle assessment showed that trichlorofluoromethane and dichlorodifluoromethane accounted for more than 99% of impact potentials to global warming and approximately 70% to human toxicity (non-carcinogenic). The major contributor for both photochemical ozone formation and ecotoxicity was ethanol. A detection threshold method was also used to evaluate odour pollution. Five compounds including methane thiol, hydrogen sulphide, ethanol, dimethyl disulphide, and dimethyl sulphide, with dilution multiples above one, were considered the critical compounds. Methane thiol showed the highest contribution to odour pollution of more than 90%, as indicated by its low threshold. Comparison of the contributions of the compounds to different environmental aspects indicated that typical pollutants varied based on specific evaluation targets and therefore should be comprehensively considered. This study provides important information and scientific methodology to elucidate the impacts of odourant compounds to the environment and odour pollution.

Assessing environmental inequalities in ambient air pollution across urban Australia.

Identifying inequalities in air pollution levels across population groups can help address environmental justice concerns. We were interested in assessing these inequalities across major urban areas in Australia. We used a land-use regression model to predict ambient nitrogen dioxide (NO2) levels and sought the best socio-economic and population predictor variables. We used a generalised least squares model that accounted for spatial correlation in NO2 levels to examine the associations between the variables. We found that the best model included the index of economic resources (IER) score as a non-linear variable and the percentage of non-Indigenous persons as a linear variable. NO2 levels decreased with increasing IER scores (higher scores indicate less disadvantage) in almost all major urban areas, and NO2 also decreased slightly as the percentage of non-Indigenous persons increased. However, the magnitude of differences in NO2 levels was small and may not translate into substantive differences in health.

Fine particulate air pollution and outpatient department visits for headache in Taipei, Taiwan.

This study was undertaken to determine whether there was an association between fine particle matter (PM(2.5)) levels and daily outpatient department visits (OPD) for headaches in Taipei, Taiwan. Daily OPD visits for headaches and ambient air pollution data for Taipei were obtained for the period 2006-2011. The relative risk of visits for OPD headaches was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single-pollutant model (without adjustment for other pollutants), increased OPD visits for headaches were significantly associated with levels of PM(2.5) both on warm days (>23°C) and cool days (<23°C), with an interquartile range rise associated with a 12% (95% CI = 10-14%) and 3% (95% CI = 1-5%) elevation in OPD visits for headaches, respectively. In the two-pollutant models, PM(2.5) remained significant after inclusion of sulfur dioxide (SO2) or ozone (O3) on both warm and cool days. This study provides evidence that higher levels of PM(2.5) increase the risk of OPD visits for headaches in Taipei, Taiwan.

The air quality health index and emergency department visits for urticaria in Windsor, Canada.

Ambient air pollution exposure has been associated with several health conditions, limited not only to respiratory and cardiovascular systems but also to cutaneous tissues. However, few epidemiological studies examined pollution exposure on skin problems. Basically, the common mechanism by which pollution may affect skin physiology is by induction of oxidative stress and inflammation. Urticaria is among the skin pathologies that have been associated with pollution. Based on the combined effects of three ambient air pollutants, ozone (O3), nitrogen dioxide (NO2), and fine particulate matter (PM) with a median aerodynamic diameter of less than 2.5 µm (PM(2.5)), on mortality, the Air Quality Health Index (AQHI) in Canada was developed. The aim of this study was to examine the associations of short-term changes in AQHI with emergency department (ED) visits for urticaria in Windsor-area hospitals in Canada. Diagnosed ED visits were retrieved from the National Ambulatory Care Reporting System (NACRS). A time-stratified case-crossover design was applied to 2905 ED visits (males = 1215; females = 1690) for urticaria from April 2004 through December 2010. Odds ratios (OR) and their corresponding 95% confidence intervals (95%CI) for ED visits associated with increase by one unit of risk index were calculated employing conditional logistic regression. Positive and significant results were observed between AQHI levels and OR for ED visits for urticaria in Windsor for lags 2 and 3 days. A distributed lag nonlinear model technique was applied to daily counts of ED visits for lags 0 to 10 and significant results were obtained from lag 2 to lag 5 and for lag 9. These findings demonstrated associations between ambient air pollution and urticarial confirming that air pollution affects skin conditions.

Associations between ozone and preterm birth in women who develop gestational diabetes.

Prenatal exposure to ambient air pollutants might cause adverse birth outcomes; however, there have been few studies in which the association between air pollution and preterm birth was examined after stratifying by pregnancy complications. We conducted a population-based case-control study of 1,510,064 singleton births from the Taiwanese birth registry during 2001-2007. Of the total of 1,510,064 births, we designated all 86,224 preterm births as the case group and then randomly selected an additional 344,896 from the remaining births (equivalent to 4 full-term births for every 1 preterm birth) as the control sample. We used an inverse distance weighting approach to calculate an average exposure parameter for air pollutants. The adjusted odds ratio for preterm birth per 10-ppb increase in ozone was 1.12 (95% confidence interval: 1.01, 1.23) for women with gestational diabetes mellitus who were exposed in the third trimester and 1.02 (95% confidence interval: 1.01, 1.03) for women without gestational diabetes (P for interaction <0.001). These findings suggest that exposure to ozone in pregnancy is associated with an increased risk of preterm birth, particularly for women who have gestational diabetes mellitus.

Investigation of carbonyl compound sources at a rural site in the Yangtze River Delta region of China.

Carbonyl compounds are important intermediates in atmospheric photochemistry, but their primary sources are still not understood well. In this work, carbonyls, hydrocarbons, and alkyl nitrates were continuously measured during November 2011 at a rural site in the Yangtze River Delta region of China. Mixing ratios of carbonyls and hydrocarbons showed large fluctuations during the entire measurement. The average level for total measured volatile organic compounds during the pollution episode from 25th to 27th November, 2011 was 91.6 ppb, about 7 times the value for the clean period of 7th-8th, November, 2011. To preliminarily identify toluene sources at this site, the emission ratio of toluene to benzene (T/B) during the pollution episode was determined based on photochemical ages derived from the relationship of alkyl nitrates to their parent alkanes. The calculated T/B was 5.8 ppb/ppb, significantly higher than the values of 0.2-1.7 ppb/ppb for vehicular exhaust and other combustion sources, indicating the dominant influence of industrial emissions on ambient toluene. The contributions of industrial sources to ambient carbonyls were then calculated using a multiple linear regression fit model that used toluene and alkyl nitrates as respective tracers for industrial emission and secondary production. During the pollution episode, 18.5%, 69.0%, and 52.9% of measured formaldehyde, acetaldehyde, and acetone were considered to be attributable to industrial emissions. The emission ratios relative to toluene for formaldehyde, acetaldehyde, and acetone were determined to be 0.10, 0.20 and 0.40 ppb/ppb, respectively. More research on industrial carbonyl emission characteristics is needed to understand carbonyl sources better.

Effects of phototherapy using different light sources on oxidant and antioxidant status of neonates with jaundice.

BACKGROUND/AIM: Neonates have limited antioxidant protective capacity. It has recently been demonstrated that phototherapy used for treatment of neonatal jaundice produces oxidative stress. Various phototherapy devices using different light sources are available for phototherapy. We aimed to investigate the effects of phototherapy applied with different light sources on the global oxidant/antioxidant status in neonates. METHODS: Term and late-preterm (≥35 weeks) newborn infants hospitalized to receive phototherapy for non-hemolytic jaundice in the 2-9 days of life were enrolled. Infants who received conventional phototherapy with fluorescent lamps were defined as group 1, intensive light emitting diode (LED) phototherapy as group 2, and fiberoptic phototherapy as group 3. The serum total antioxidant capacity (TAC) and total oxidant status (TOS) were measured before and 24 h after phototherapy. Oxidative stress index (OSI) was calculated. RESULTS: Twenty nine patients were included in each group. At the beginning of phototherapy serum TAC, TOS and OSI levels were similar in all groups. After phototherapy serum TAC decreased significantly in all three groups (p < 0.001). Total oxidant status increased significantly in group 1 (p < 0.001) and group 2 (p = 0.001) whereas a statistically insignificant increase was observed in group 3 (p = 0.057). After phototherapy OSI increased significantly in group 1 (p < 0.001), group 2 (p = 0.001), and group 3 (p = 0.038). CONCLUSION: As indicated by increased OSI, oxidant/antioxidant balance is disturbed in favor of oxidants after blue fluorescent light, LED and fiberoptic phototherapy.

Investigating the association between birth weight and complementary air pollution metrics: a cohort study.

BACKGROUND: Exposure to air pollution is frequently associated with reductions in birth weight but results of available studies vary widely, possibly in part because of differences in air pollution metrics. Further insight is needed to identify the air pollution metrics most strongly and consistently associated with birth weight. METHODS: We used a hospital-based obstetric database of more than 70,000 births to study the relationships between air pollution and the risk of low birth weight (LBW, <2,500 g), as well as birth weight as a continuous variable, in term-born infants. Complementary metrics capturing different aspects of air pollution were used (measurements from ambient monitoring stations, predictions from land use regression models and from a Gaussian dispersion model, traffic density, and proximity to roads). Associations between air pollution metrics and birth outcomes were investigated using generalized additive models, adjusting for maternal age, parity, race/ethnicity, insurance status, poverty, gestational age and sex of the infants. RESULTS: Increased risks of LBW were associated with ambient O(3) concentrations as measured by monitoring stations, as well as traffic density and proximity to major roadways. LBW was not significantly associated with other air pollution metrics, except that a decreased risk was associated with ambient NO(2) concentrations as measured by monitoring stations. When birth weight was analyzed as a continuous variable, small increases in mean birth weight were associated with most air pollution metrics (<40 g per inter-quartile range in air pollution metrics). No such increase was observed for traffic density or proximity to major roadways, and a significant decrease in mean birth weight was associated with ambient O3 concentrations. CONCLUSIONS: We found contrasting results according to the different air pollution metrics examined. Unmeasured confounders and/or measurement errors might have produced spurious positive associations between birth weight and some air pollution metrics. Despite this, ambient O(3) was associated with a decrement in mean birth weight and significant increases in the risk of LBW were associated with traffic density, proximity to roads and ambient O(3). This suggests that in our study population, these air pollution metrics are more likely related to increased risks of LBW than the other metrics we studied. Further studies are necessary to assess the consistency of such patterns across populations.

Assessment of ozone variations and meteorological influences in a tourist and health resort area on the island of Mali Losinj (Croatia).

The purpose of this study was to investigate ozone, variations, and its correlation with meteorological parameters at a remote location on the Mali Losinj Island, which has been a tourist and health resort area in the northern Adriatic. The measured data are discussed in relation to the EU guidelines (Directive 2002/3/EC; Directive 2008/50/EC). In order to characterize ambient air with respect to ozone vegetation injury and photochemical pollution, we calculated accumulated dose over a threshold of 40 parts per billion index and two photochemical pollution indicators. The influence of local meteorological parameters on the measured ozone volume fractions was also investigated. We used the multivariate technique principal component analysis to trace correlations between measured ozone concentration and meteorological parameters.