Ambient NO2 Concentrations Research Articles

ANALISIS PERUBAHAN KONSENTRASI NITROGEN DIOKSIDA (NO2) PADA AREA BERVEGETASI DAN TIDAK BERVEGETASI DI JALAN SIMPANG SUSUN

The Interchange of highway is the intersection of several roads that consists of numerous road levels. It causes great number of traffic volume and releases vast pollutant quantities. This research objective were to analyze the influence of wind speed and traffic volume with NO2 concentrations at the surrounding of the interchange road. Researches were conducted at Cikunir interchange, between JORR E1 (Taman Mini-Cikunir segment), JORR E2 (Cikunir-Cakung), and Jakarta-Cikampek toll road. Concentration of NO2 gas was measured at the point of 0 m, 10 m, and 75 m from the shoulder in the green belt plot and in the plot having no green belt. The results showed that there is a significant correlation between traffic volume with ambient NO2 concentration. The correlation level between the volume of vehicle with NO2 concentration is 0.925 (very strong). Wind speed did not have a significant correlation with NO2 concentrations. Volume of vehicles and wind speed simultaneously (together) have a significant correlation on the NO2 concentration.

Mitochondrial DNA content in blood and carbon load in airway macrophages. A panel study in elderly subjects

BackgroundMitochondria are sensitive to air pollutants due to their lack of repair capacity. Changes in mitochondrial DNA copy number (mtDNAcn) or content is a proxy of mitochondrial damage and has been associated with recent exposure to traffic-derived air pollutants, nitrogen dioxide (NO2) and black carbon (BC). Inhaled BC can be phagocytosed by airway macrophages (AMs), and its amount in AM reflects personal exposure to traffic-related air pollution. ObjectivesThe present study investigated the relation between the internal marker AM BC and ambient NO2 concentration and examined the associations of mtDNAcn with NO2 and AM BC. MethodsA panel of 20 healthy retired participants (10 couples) living in Belgium underwent repeated assessments of health and air pollution exposure at 11 time points over one year. We increased exposure contrast temporarily by moving participants for 10 days to Milan, Italy (high exposure) and to Vindeln, Sweden (low exposure). Personal exposure to NO2 was measured during 5 consecutive days prior to each assessment time point. The amount of BC was assessed by image analysis in AMs retrieved from induced sputum collected at 7 time points. Blood mtDNAcn was determined by qPCR at each time point. Associations between AM BC and NO2, and of mtDNAcn with NO2 and AM BC were estimated using linear mixed effect models adjusted for covariates and potential confounders. ResultsMean concentrations of 5-day average NO2 were higher in Milan (64 μg/m3) and lower in Vindeln (4 μg/m3) than Belgium (26 μg/m3). Each 10 μg/m3 increment in NO2 exposure during the last 5 days was associated with 0.07 μm2 (95% CI: 0.001 to 0.012) increase in median area of AM BC. A 10 μg/m3 increase in NO2 was associated with 3.9% (95% CI: 2.2 to 5.5%) decrease in mtDNAcn. Consistently, each 1 μm2 increment in median area of AM BC was associated with 24.8% (95% CI: 6.8 to 39.3%) decrease in mtDNAcn. ConclusionIn this quasi-experimental setting involving moving persons to places with high and low ambient air pollution, we found changes in AM BC according to ambient air pollution levels measured during the previous 5 days. Both higher ambient NO2 and the internal lung BC load, paralleled mitochondrial compromises as exemplified by lower mtDNA content.

Mid-IR spectrometer for mobile, real-time urban NO<sub>2</sub> measurements

Abstract. Detailed knowledge about the urban NO2 concentration field is a key element for obtaining accurate pollution maps and individual exposure estimates. These are required for improving the understanding of the impact of ambient NO2 on human health and for related air quality measures. However, city-scale NO2 concentration maps with high spatio-temporal resolution are still lacking, mainly due to the difficulty of accurate measurement of NO2 at the required sub-ppb level precision. We contribute to close this gap through the development of a compact instrument based on mid-infrared laser absorption spectroscopy. Leveraging recent advances in infrared laser and detection technology and a novel circular absorption cell, we demonstrate the feasibility and robustness of this technique for demanding mobile applications. A fully autonomous quantum cascade laser absorption spectrometer (QCLAS) has been successfully deployed on a tram, performing long-term and real-time concentration measurements of NO2 in the city of Zurich (Switzerland). For ambient NO2 concentrations, the instrument demonstrated a precision of 0.23 ppb at one second time resolution and of 0.03 ppb after 200 s averaging. Whilst the combined uncertainty estimated for the retrieved spectroscopic values was less than 5 %, laboratory intercomparison measurements with standard CLD instruments revealed a systematic NO2 wall loss of about 10 % within the laser spectrometer. For the field campaign, the QCLAS has been referenced to a CLD using urban atmospheric air, despite the potential cross sensitivity of CLD to other nitrogen containing compounds. However, this approach allowed a direct comparison and continuous validation of the spectroscopic data to measurements at regulatory air quality monitoring (AQM) stations along the tram-line. The analysis of the recorded high-resolution time series allowed us to gain more detailed insights into the spatio-temporal concentration distribution of NO2 in an urban environment. Furthermore, our results demonstrate that for reliable city-scale concentration maps a larger data set and better spatial coverage is needed, e.g., by deploying more mobile and stationary instruments to account for mainly two shortcomings of the current approach: (i) limited residence time close to sources with large short-term NO2 variations, and (ii) insufficient representativeness of the tram tracks for the complex urban environment.

Association between ambient air pollution and pregnancy rate in women who underwent IVF.

Are the concentrations of five criteria air pollutants associated with probabilities of biochemical pregnancy loss and intrauterine pregnancy in women? Increased concentrations of ambient particulate matter (PM10), nitrogen dioxide (NO2), carbon monoxide (CO) during controlled ovarian stimulation (COS) and after embryo transfer were associated with a decreased probability of intrauterine pregnancy. Exposure to high ambient air pollution was suggested to be associated with low fertility and high early pregnancy loss in women. Using a retrospective cohort study design, we analysed 6621 cycles of 4581 patients who underwent one or more fresh IVF cycles at a fertility centre from January 2006 to December 2014, and lived in Seoul at the time of IVF treatment. To estimate patients' individual exposure to air pollution, we computed averages of hourly concentrations of five air pollutants including PM10, NO2, CO, sulphur dioxide (SO2) and ozone (O3) measured at 40 regulatory monitoring sites in Seoul for each of the four exposure periods: period 1 (start of COS to oocyte retrieval), period 2 (oocyte retrieval to embryo transfer), period 3 (embryo transfer to hCG test), and period 4 (start of COS to hCG test). Hazard ratios (HRs) from the time-varying Cox-proportional hazards model were used to estimate probabilities of biochemical pregnancy loss and intrauterine pregnancy for an interquartile range (IQR) increase in each air pollutant concentration during each period, after adjusting for individual characteristics. We tested the robustness of the result using generalised linear mixed model, accounting for within-woman correlation. Mean age of the women was 35 years. Average BMI was 20.9 kg/m2 and the study population underwent 1.4 IVF cycles on average. Cumulative pregnancy rate in multiple IVF cycles was 51.3% per person. Survival analysis showed that air pollution during periods 1 and 3 was generally associated with IVF outcomes. Increased NO2 (adjusted HR = 0.93, 95% CI: 0.87, 0.99) and CO (0.94, 95% CI: 0.89, 1.00) during period 1 were associated with decreased probability of intrauterine pregnancy. PM10 (0.92, 95% CI: 0.85, 0.99), NO2 (0.93, 95% CI = 0.86, 1.00) and CO (0.93, 95% CI: 0.87, 1.00) levels during period 3 were also inversely associated with intrauterine pregnancy. Both PM10 (1.17, 95% CI: 1.04 1.33) and NO2 (1.18, 95% CI: 1.03, 1.34) during period 3 showed positive associations with biochemical pregnancy loss. The district-specific ambient air pollution treated as an individual exposure may not represent the actual level of each woman's exposure to air pollution. Smoking, working status, parity or gravidity of women, and semen analysis data were not included in the analysis. This study provided evidence of an association between increased ambient concentrations of PM10, NO2 and CO and reduced probabilities for achieving intrauterine pregnancy using multiple IVF cycle data. Specifically, our results indicated that lower intrauterine pregnancy rates in IVF cycles may be linked to ambient air pollution during COS and the post-transfer period. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2013 R1A6A3A04059017, 2016 R1D1A1B03933410 and 2018 R1A2B6004608) and the National Cancer Center of Korea (NCC-1810220-01). The authors report no conflicts of interest. N/A.

Satellite-Based Estimates of Daily NO2 Exposure in China Using Hybrid Random Forest and Spatiotemporal Kriging Model.

A novel model named random-forest-spatiotemporal-kriging (RF-STK) was developed to estimate the daily ambient NO2 concentrations across China during 2013-2016 based on the satellite retrievals and geographic covariates. The RF-STK model showed good prediction performance, with cross-validation R2 = 0.62 (RMSE = 13.3 μg/m3) for daily and R2 = 0.73 (RMSE = 6.5 μg/m3) for spatial predictions. The nationwide population-weighted multiyear average of NO2 was predicted to be 30.9 ± 11.7 μg/m3 (mean ± standard deviation), with a slowly but significantly decreasing trend at a rate of -0.88 ± 0.38 μg/m3/year. Among the main economic zones of China, the Pearl River Delta showed the fastest decreasing rate of -1.37 μg/m3/year, while the Beijing-Tianjin Metro did not show a temporal trend ( P = 0.32). The population-weighted NO2 was predicted to be the highest in North China (40.3 ± 10.3 μg/m3) and lowest in Southwest China (24.9 ± 9.4 μg/m3). Approximately 25% of the population lived in nonattainment areas with annual-average NO2 > 40 μg/m3. A piecewise linear function with an abrupt point around 100 people/km2 characterized the relationship between the population density and the NO2, indicating a threshold of aggravated NO2 pollution due to urbanization. Leveraging the ground-level NO2 observations, this study fills the gap of statistically modeling nationwide NO2 in China, and provides essential data for epidemiological research and air quality management.

Self-powered room temperature NO2 detection driven by triboelectric nanogenerator under UV illumination

The triboelectric nanogenerator (TENG) driven self-powered gas sensor has been developed for room temperature nitrogen dioxide (NO2) detection under UV illumination (365 nm). Powered by TENG, the concentration of NO2 can be spontaneously detected via chemoresistive gas sensor based on Zinc Oxide-Reduced graphene oxide (ZnO-RGO) hybrid films, where the voltage drop across the interdigital electrodes (IDEs) has a proportional relationship with NO2 concentration. The self-powered triboelectric gas sensor (TGS) composed by ZnO-RGO composite films exhibit superior response (~ 16.8) and sensitivity as well as selectivity than that for pure ZnO film. With respect to selectivity, the response of ZnO-RGO composite film based TGS to NO2 was at least 49-fold higher than those for other gases. Furthermore, through a signal processing circuit, a self-powered NO2 gas alert system was developed for real-time monitoring the ambient NO2 concentration. This work not only promotes the applicability of TENGs as self-powered sensors but also pushes forwards the active sensing network node for environmental monitoring by harvesting ambient energy.

Case-Crossover and Nested Case-Control Analyses of the Association between Mortality and Spatially-Resolved Daily Ambient Concentrations of NO2 among Elderly Persons with Congestive Heart Failure, Montreal, 1991-2002

Case-Crossover and Nested Case-Control Analyses of the Association between Mortality and Spatially-Resolved Daily Ambient Concentrations of NO2 among Elderly Persons with Congestive Heart Failure, Montreal, 1991-2002

Highway pollution effects on microhabitat community structure of corticolous lichens

We studied lichen communities on bole and base tree trunk segments along forest edge-to-interior gradients on opposite sides of a major highway and a control site in central North Carolina, U.S.A., to investigate if these two communities differ and if so, do they differ in response to highway pollution. At each site we measured various environmental parameters including ambient air NO2 concentrations, and sampled lichens on 5–7 trees along each of five parallel transects established at the forest edge and at 25, 60, 100 and 150 m into the forest. We compared lichen communities between the two trunk segments via species richness and composition by habit, photobiont type, and reproductive strategy. We then ran dual (bole and base) NMS ordinations with subsequent correlation/regression analyses to explore/test relationships of lichen parameters with environmental variables among the 15 sample transects combined. Species richness was similar between trunk segments at transect and site levels as well as overall. Bole and base communities were more compositionally similar to each other at the highway sites than they were at the control site, based on Bray-Curtis similarity indices (BC). Tree base communities differed in terms of functional groupings, with greater proportions of squamulose, cyanolichen and sterile species than found in tree bole communities, but varyingly so among sites. Patterns of bole-base BC values with distance from the forest edge were not apparent in any of the sites. Ordination analyses resulted in Axis 1 representing most of the variation for each trunk segment. Along this axis, correlations were similar between boles and bases, with the strongest ones involving lichen species richness (negative) and NO2 concentrations (positive); notably weak correlations involved tree species number, canopy cover and DBH. Similar patterns were found when lichen species number was correlated with environmental parameters directly, with NO2 concentration correlating strongest at each trunk segment. Among functional groups, % crustose and % fertile species on bases correlated significantly with NO2. Lichen species–NO2 relationships on boles and bases were both found to be highly significant quadratic relationships with base lichen richness being stronger.

Air pollution and subclinical interstitial lung disease: the Multi-Ethnic Study of Atherosclerosis (MESA) air-lung study.

We studied whether ambient air pollution is associated with interstitial lung abnormalities (ILAs) and high attenuation areas (HAAs), which are qualitative and quantitative measurements of subclinical interstitial lung disease (ILD) on computed tomography (CT).We performed analyses of community-based dwellers enrolled in the Multi-Ethnic Study of Atherosclerosis (MESA) study. We used cohort-specific spatio-temporal models to estimate ambient pollution (fine particulate matter (PM2.5), nitrogen oxides (NOx), nitrogen dioxide (NO2) and ozone (O3)) at each home. A total of 5495 participants underwent serial assessment of HAAs by cardiac CT; 2671 participants were assessed for ILAs using full lung CT at the 10-year follow-up. We used multivariable logistic regression and linear mixed models adjusted for age, sex, ethnicity, education, tobacco use, scanner technology and study site.The odds of ILAs increased 1.77-fold per 40 ppb increment in NOx (95% CI 1.06 to 2.95, p = 0.03). There was an overall trend towards an association between higher exposure to NOx and greater progression of HAAs (0.45% annual increase in HAAs per 40 ppb increment in NOx; 95% CI -0.02 to 0.92, p = 0.06). Associations of ambient fine particulate matter (PM2.5), NOx and NO2 concentrations with progression of HAAs varied by race/ethnicity (p = 0.002, 0.007, 0.04, respectively, for interaction) and were strongest among non-Hispanic white people.We conclude that ambient air pollution exposures were associated with subclinical ILD.

A Statistical Analysis of the Relationship between Brown Haze and Surface Air Pollution Levels on Respiratory Hospital Admissions in Auckland, New Zealand

Eleven years of hospital admissions data for Auckland, New Zealand for respiratory conditions are analyzed using a Poisson regression modelling approach, incorporating a spline function to represent time, based on a detailed record of haze events and surface air pollution levels over an eleven-year period, taking into account the daily average temperature and humidity, the day of the week, holidays and trends over time. NO2 was the only pollutant to show a statistically significant increase (p = 0.009) on the day of the haze event for the general population. Ambient concentrations of CO, NO and NO2 were significantly associated with admissions with an 11-day lag period for the 0–14 year age group and a 5–7 day lag period for the 65+ year age group. A 3-day lag period was found for the 15–64 year age group for CO, NO and PM10. Finally, the incidence of brown haze was linked to significant increases in hospital admissions. A lag period of 5 days was recorded between haze and subsequent increases in admissions for the 0–14 year age group and the 65+ group and an 11-day lag for the 15–64 year age group. The results provide the first statistical link between Auckland brown haze events, surface air pollution and respiratory health. Medical institutions and practitioners could benefit from improved capacity to predict Auckland’s brown haze events in order prepare for the likely increases in respiratory admissions over the days ahead.

Acute respiratory symptoms associated with short term fluctuations in ambient pollutants among schoolchildren in Durban, South Africa.

Ambient air pollution has been associated with adverse respiratory outcomes, especially among children with asthma. This study reports on associations between daily ambient air pollutant concentrations and the respiratory symptoms of schoolchildren living in Durban, South Africa. This city is Africa's busiest port and a key hub for imported crude oil and exported refined petroleum and petrochemical products, and it experiences a mixture of air pollutants that reflects emissions from industry, traffic and biomass burning. Children in four communities in the highly industrialized southern portion of the city were compared to children of similar socio-economic profiles living in the north of the city. One school was selected in each community. A total of 423 children were recruited. Symptom logs were completed every 1.5-2h over 3-week period in each of four seasons. Ambient concentrations of NO2, NO, SO2, CO, O3, PM2.5 and PM10 were measured throughout the study. Generalized estimating equation (GEE) models were used to estimate odds ratios (ORs) and assess lag effects (1-5 days) using single pollutant (single lags or distributed lags) models. Concentrations of SO2 and NOx were markedly higher in the south, while PM10 did not vary. Significant increase in the odds ratios of cough were identified for the various lags analyzed. The OR of symptoms was further increased among those living in the south compared to the north. In conclusion, in this analysis of over 70,000 observations, we provide further evidence that exposure to PM10, SO2, NO2 and NO is associated with significantly increased occurrence of respiratory symptoms among children. This was evident for cough, shortness of breath, and chest tightness, across the four pollutants and for different lags of exposure. This is the first study describing these changes in sub-Saharan Africa.

Potential reductions in ambient NO2 concentrations from meeting diesel vehicle emissions standards

Exceedances of the concentration limit value for ambient nitrogen dioxide (NO2) at roadside sites are an issue in many cities throughout Europe. This is linked to the emissions of light duty diesel vehicles which have on-road emissions that are far greater than the regulatory standards. These exceedances have substantial implications for human health and economic loss. This study explores the possible gains in ambient air quality if light duty diesel vehicles were able to meet the regulatory standards (including both emissions standards from Europe and the United States). We use two independent methods: a measurement-based and a model-based method. The city of Berlin is used as a case study. The measurement-based method used data from 16 monitoring stations throughout the city of Berlin to estimate annual average reductions in roadside NO2 of 9.0 to 23 µg m−3 and in urban background NO2 concentrations of 1.2 to 2.7 µg m−3. These ranges account for differences in fleet composition assumptions, and the stringency of the regulatory standard. The model simulations showed reductions in urban background NO2 of 2.0 µg m−3, and at the scale of the greater Berlin area of 1.6 to 2.0 µg m−3 depending on the setup of the simulation and resolution of the model. Similar results were found for other European cities. The similarities in results using the measurement- and model-based methods support our ability to draw robust conclusions that are not dependent on the assumptions behind either methodology. The results show the significant potential for NO2 reductions if regulatory standards for light duty diesel vehicles were to be met under real-world operating conditions. Such reductions could help improve air quality by reducing NO2 exceedances in urban areas, but also have broader implications for improvements in human health and other benefits.

Design of an ozone and nitrogen dioxide sensor unit and its long-term operation within a sensor network in the city of Zurich

Abstract. This study focuses on the investigation and quantification of low-cost sensor performance in application fields such as the extension of traditional air quality monitoring networks or the replacement of diffusion tubes. For this, sensor units consisting of two boxes featuring NO2 and O3 low-cost sensors and wireless data transfer were engineered. The sensor units were initially operated at air quality monitoring sites for 3 months for performance analysis and initial calibration. Afterwards, they were relocated and operated within a sensor network consisting of six locations for more than 1 year. Our analyses show that the employed O3 and NO2 sensors can be accurate to 2–5 and 5–7 ppb, respectively, during the first 3 months of operation. This accuracy, however, could not be maintained during their operation within the sensor network related to changes in sensor behaviour. For most of the O3 sensors a decrease in sensitivity was encountered over time, clearly impacting the data quality. The NO2 low-cost sensors in our configuration exhibited better performance but did not reach the accuracy level of NO2 diffusion tubes (∼ 2 ppb for uncorrected 14-day average concentrations). Tests in the laboratory revealed that changes in relative humidity can impact the signal of the employed NO2 sensors similarly to changes in ambient NO2 concentration. All the employed low-cost sensors need to be individually calibrated. Best performance of NO2 sensors is achieved when the calibration models also include time-dependent parameters accounting for changes in sensor response over time. Accordingly, an effective procedure for continuous data control and correction is essential for obtaining meaningful data. It is demonstrated that linking the measurements from low-cost sensors to the high-quality measurements from routine air quality monitoring stations is an effective procedure for both tasks provided that time periods can be identified when pollutant concentrations can be accurately predicted at sensor locations.

Soil trace gas fluxes along orthogonal precipitation and soil fertility gradients in tropical lowland forests of Panama

Abstract. Tropical lowland forest soils are significant sources and sinks of trace gases. In order to model soil trace gas flux for future climate scenarios, it is necessary to be able to predict changes in soil trace gas fluxes along natural gradients of soil fertility and climatic characteristics. We quantified trace gas fluxes in lowland forest soils at five locations in Panama, which encompassed orthogonal precipitation and soil fertility gradients. Soil trace gas fluxes were measured monthly for 1 (NO) or 2 (CO2, CH4, N2O) years (2010–2012) using vented dynamic (for NO only) or static chambers with permanent bases. Across the five sites, annual fluxes ranged from 8.0 to 10.2 Mg CO2-C, −2.0 to −0.3 kg CH4-C, 0.4 to 1.3 kg N2O-N and −0.82 to −0.03 kg NO-N ha−1 yr−1. Soil CO2 emissions did not differ across sites, but they did exhibit clear seasonal differences and a parabolic pattern with soil moisture across sites. All sites were CH4 sinks; within-site fluxes were largely controlled by soil moisture, whereas fluxes across sites were positively correlated with an integrated index of soil fertility. Soil N2O fluxes were low throughout the measurement years, but the highest emissions occurred at a mid-precipitation site with high soil N availability. Net negative NO fluxes at the soil surface occurred at all sites, with the most negative fluxes at the low-precipitation site closest to Panama City; this was likely due to high ambient NO concentrations from anthropogenic sources. Our study highlights the importance of both short-term (climatic) and long-term (soil and site characteristics) factors in predicting soil trace gas fluxes.

Correlation of atmospheric purity index to the diversity of lichens in the Horton Plains National Park, Sri Lanka

Horton Plains National Park (HPNP) has been declared as a world heritage site, because of its unique biodiversity. Die-back of certain areas of this park is widely believed to be due to acidic precursor depositions carried over from other parts of the country and also from neighboring countries. Air pollution data for the two pollutants, NO2 and SO2 were obtained from the passive air sampling method. The data revealed that the concentrations of ambient NO2 and SO2 were very low in the HPNP. The variations of ambient NO2 and SO2 concentrations during the study period showed insignificant positive correlation (p≥ 0.05) with the rainfall data. Considering the variations of these two pollutants with Relative Humidity and the number of vehicles visiting HPNP, both pollutants had insignificant positive correlation. The Index of Atmospheric Purity (IAP) value obtained for the whole area of the HPNP was 54.22. This value belongs to the quality level 5 which represents the ‘very low’ pollution level. The results including lichen distribution and air quality data could confirm that the ambient air quality at HPNP is very high. The high diversity of lichens and the minimum levels of air pollutants suggested that the forest health of HPNP is at a favorable level. Therefore, it is essential to maintain at least the current air pollution level of HPNP in order to conserve the forest and its biodiversity.

Multi-dimension apportionment of clean air “parade blue” phenomenon in Beijing

The mass concentration and major chemical components of fine particulate matter were measured before, during and after Beijing's massive parade commemorating 70th anniversary of the Chinese Victory in World War II on September 3, 2015. Regional emission inventory, positive matrix factorization (PMF), observations from space and backward air mass trajectories were jointly applied to identify the major pollution sources and their temporal and spatial variations. The contributions of emissions variations and the meteorological conditions related to the “parade blue” phenomenon in Beijing and its surrounding areas were investigated in detail. The main cause of the decreased PM2.5 mass concentration was attributed to the absolute reduction in emissions of primary air pollutants. The chemical composition of PM2.5 varied significantly before, during and after the parade. Fugitive dust particles were well controlled, the secondary formation of PM2.5 was reduced along with the controlled gaseous precursors' emissions from vehicles and industrial sources during the temporary intensified control period. During the parade period, the SO2 and NO2 column concentrations in Beijing and the surrounding areas decreased sharply, indicating that the coordinated reduction in primary emissions from the surrounding areas of Beijing played an important role in lowering the ambient concentration of SO2 and NO2 and accordingly lowered PM2.5 and improved the regional air quality. A comparison of the temperature, humidity, and wind speed and direction during the same periods in 2014 and 2015 showed that the meteorological conditions positively influenced the achievement of “parade blue”.

Association between ambient PM(l0)/PM(2.5) concentration and outpatient department visits due to respiratory disease in a hospital in Jinan, 2013-2015: a time series analysis

Objective: To estimate the influence of the ambient PM(l0) and PM(2.5) pollution on the hospital outpatient department visit due to respiratory diseases in local residents in Jinan quantitatively. Methods: Time serial analysis using generalized addictive model (GAM) was conducted. After controlling the confounding factors, such as long term trend, weekly pattern and meteorological factors, considering lag effect and the influence of other air pollutants, the excess relative risks of daily hospital visits associated with increased ambient PM(10) and PM(2.5) levels were estimated by fitting a Poisson regression model. Results: A 10 μg/m(3) increase of PM(10) and PM(2.5) levels was associated with an increase of 0.36%(95%CI: 0.30%-0.43%) and 0.50%(95%CI: 0.30%-0.70%) respectively for hospital visits due to respiratory diseases. Lag effect of 6 days was strongest, the excess relative risks were 0.65% (95% CI: 0.58% -0.71% ) and 0.54% (95% CI: 0.42%-0.67%) respectively. When NO(2) concentration was introduced, the daily hospital visits due to respiratory disease increased by 0.83% as a 10 μg/m(3) increase of PM(10) concentration (95% CI: 0.76%-0.91%). Conclusion: The ambient PM(l0) and PM(2.5) pollution was positively associated with daily hospital visits due to respiratory disease in Jinan, and ambient NO(2) concentration would have the synergistic effect.

Health risk of inhalation exposure to sub-10 µm particulate matter and gaseous pollutants in an urban-industrial area in South Africa: an ecological study

ObjectiveTo assess the health risks associated with exposure to particulate matter (PM10), sulphur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO) and ozone (O3).DesignThe study is an ecological study that...

Detrended cross-correlation analysis of urban traffic congestion and NO2 concentrations in Chengdu

In urban congested road sections, usually there exhibits elevated exhaust emissions due to longer idling and more frequent acceleration of vehicles. Using detrended cross-correlation analysis (DCCA), the relationship between air pollution and traffic congestion in the urban area of Chengdu was investigated. In order for a better quantification of the congested condition in a relatively large spatial region, a new measure, i.e., the congestion length (CL), is developed, extracted, and estimated using the Google Real-Time Traffic Maps and GIS technology. Relationships between the hourly average congestion length (HACL) and NO2 concentrations in the urban area of Chengdu from 12 May to 17 May, 2013 were analyzed. A high long-term cross-correlation between HACL and NO2 was observed, implying the ambient NO2 concentration fluctuations are positively cross-correlated with urban traffic congestion in the form of a power function. However, the ambient NO2 concentration did not respond immediately to the change of road traffic due to a relatively slow and lagged photochemical reaction process. A time lagged cross-correlation was further analyzed and showed that the time lag could be as large as 10h. These findings can be used for improving air quality forecasting accuracy by taking into account the time lags in correlation between emissions and air quality.

Staggering reductions in atmospheric nitrogen dioxide across Canada in response to legislated transportation emissions reductions

It is well established that atmospheric nitrogen dioxide (NO2), associated mainly with emissions from transportation and industry, can have adverse effects on both human and ecosystem health. Specifically, atmospheric NO2 plays a role in the formation of ozone, and in acidic and nutrient deposition. As such, international agreements and national legislation, such as the On-Road Vehicle and Engine Emission Regulations (SOR/2003-2), and the Federal Agenda on Cleaner Vehicles, Engines and Fuel have been put into place to regulate and limit oxidized nitrogen emissions. The objective of this study was to assess the response of ambient air concentrations of NO2 across Canada to emissions regulations. Current NO2 levels across Canada were examined at 137 monitoring sites, and long-term annual and quarterly trends were evaluated for 63 continuous monitoring stations that had at least 10 years of data during the period 1988–2013. A non-parametric Mann-Kendall test (Z values) and Sen's slope estimate were used to determine monotonic trends; further changepoint analysis was used to determine periods with significant changes in NO2 air concentration and emissions time-series data. Current annual average NO2 levels in Canada range between 1.16 and 14.96 ppb, with the national average being 8.43 ppb. Provincially, average NO2 ranges between 3.77 and 9.25 ppb, with Ontario and British Columbia having the highest ambient levels of NO2. Long-term tend analysis indicated that the annual average NO2 air concentration decreased significantly at 87% of the stations (55 of 63), and decreased non-significantly at 10% (5 of 63) during the period 1998–2013. Concentrations increased (non-significantly) at only 3% (2 of 63) of the sites. Quarterly long-term trends showed similar results; significant decreases occurred at 84% (January–March), 88% (April–June), 83% (July–September), and 81% (October–December) of the sites. Declines in transportation emissions had the most influence on NO2 air concentrations, and changepoint analysis identified three significant changepoints for the air concentration of NO2 and transportation emissions data. The air concentration changepoints occurred immediately following changepoints in transportation emissions. The introduction of emissions limiting legislation, primarily from transportation sources, has lead to dramatic decreases of 32% in NO× emissions (42% from transportation sources [road, rail, air, marine]) and 47% in ambient NO2 concentrations across Canada. With respect to human health, legislated changes in transportation emissions have the greatest impact on ambient concentration in urban areas.