|Development of air quality forecasting system in Macedonia, based on WRF-Chem model|
Urban air quality is composed of a complex interaction of factors associated with anthropogenic emissions, atmospheric circulation, and geographic factors; also, most of the urban pollution presents aerosols and trace gases toxic to human health and responsible for damaged flora, fauna, and materials. The air quality system based on the state-of-the-art Weather Research and Forecasting model coupled with chemistry (WRF-Chem) has been configured and designed for Macedonia. An extensive set of experiments have been performed with different model settings to forecast simultaneously the weather and air pollution over Macedonia. For the present work, a numerical simulation of extreme pollution episode over the urban area in Skopje has been simulated using 1-km WRF-Chem model and a newly developed set of urban mobile emissions. The modeled results implied that the model is very sensitive to the initial meteorological conditions, grid spacing, and mobile emissions. The results are validated against available observations for meteorological fields and pollutant concentrations. While the model forecasts with coarser horizontal grid resolution well fit with the hourly values of some air quality monitoring stations, these experiments tend to underpredict the peak level of about 1250 μg/m3 evidenced at the air quality station "Karpos." A WRF-Chem 5-km simulation shows increased PM10 concentrations with a peak value of about 1325 μg/m3 a few hours before the evidenced extreme concentration while 2.5-km grid run indicates the initial accumulation of air pollution with relatively high concentration with peak PM10 on 5 February 2017 at 0100 UTC. The 1-km model configuration well captures the PM10distribution over Skopje valley and the location and timing of the maximum measured air pollution. The verification analysis indicates that the best performance in the sense of the correlation coefficient is achieved with the 5-km WRF-Chem v.3.91 forecast. Numerical simulations with coarser grid resolution show less confidence and lower CC. The results suggest that model initialization and initial data using a mobile source emission provide a better quantitative assessment of extreme air pollution in urban areas. Overall, the present case study shows that the WRF-Chem model has an acceptable performance for meteorological variables as well as PM10concentration over Skopje. This study provides a general overview of WRF-Chem simulations and can serve as a reference for future air quality modeling studies.
|Complex analysis focused on influence of biodiesel and its mixture on regulated and unregulated emissions of motor vehicles with the aim to protect air quality and environment|
The main task of this study is to perform a complex analysis dealing with influence of biodiesel and its mixture on regulated and unregulated gaseous emissions of diesel engine, which is installed in a motorcar as a driving unit determined for standard road traffic. As a real technical platform intended for realisation of the required experiments, a motor vehicle equipped with the TDI engine was chosen because just this kind of engine was directly affected by the affair "dieselgate". This type of piston combustion engine is widely used in the traffic, together with negative impacts on the air quality. Various diesel fuel mixtures, which represented the applied experimental fuels, were created by mixing of the ultra-low sulphur diesel fuel (ULSDF) with the biodiesel, using different mixture ratios. The individual experiments were performed during a 13-mode test cycle especially developed for the diesel engine in such a way, so that it was possible to identify influence of the engine loading and engine speed on the regulated and unregulated gaseous emissions of the given TDI diesel engine. It is possible to say according to the obtained results that a higher portion of the biodiesel in the fuel mixture reduces the amount of the hydrocarbons (HC), carbon monoxide (CO) and particulate matters (PM) in the gaseous emissions, but it increases volume of the nitrogen oxides (NOX). A higher portion of the biodiesel causes a growth of the formaldehyde emissions and acetaldehyde emissions in the case of unregulated diesel engine emissions. The same trend is also typical for the 1,3-butadiene, propene and ethene. The biodiesel additive increases emissions of benzene; however, it reduces emissions of the toluene and xylene within the aromatic substance emissions. The obtained results confirm a fact that all the gaseous emissions are influenced by the engine operational regimes, especially by the engine loading status.
|Uncertainty associated with ambient ozone metrics in epidemiologic studies and risk assessments|
Epidemiologic studies relating ambient ozone concentrations to adverse health outcomes have typically relied on spatial averages of concentrations from nearby monitoring stations, referred to as "composite monitors." This practice reflects the assumption that ambient ozone concentrations within an urban area are spatially homogenous. We tested the validity of this assumption by comparing ozone data measured at individual monitoring sites within selected US urban areas to their respective composite monitor time series. We first characterized the temporal correlation between the composite monitor and individual monitors in each area. Next, we analyzed the heteroskedasticity of each relationship. Finally, we compared the distribution of concentrations measured at individual monitors to the composite monitor distribution. Individual monitors showed high correlation with the composite monitor over much of the range of ambient ozone concentrations, though correlations were lower at higher concentrations. The variance between individual monitors and the composite monitor increased as a function of concentration in nearly all the urban areas. Finally, we observed statistical bias in the composite monitor concentrations at the high end of the distribution. The degree to which these results introduce uncertainty into studies that utilize composite monitors depends on the contributions of peak ozone concentrations to reported health effect associations.
|International prevalence of chemical sensitivity, co-prevalences with asthma and autism, and effects from fragranced consumer products|
Chemical sensitivity is a medical condition characterized by adverse health effects from exposure to common chemical pollutants and products. This study investigated the prevalence of chemical sensitivity in four countries—the United States (US), Australia (AU), Sweden (SE), and the United Kingdom (UK). In addition, it investigated the co-prevalence of chemical sensitivity with medically diagnosed multiple chemical sensitivities (MCS), fragrance sensitivity (health problems from fragranced products), asthma/asthma-like conditions, and autism/autism spectrum disorders (ASDs). Using nationally representative population samples in each country, data were collected in June 2016 and June 2017 through on-line cross-sectional surveys of adults (n = 4435). Results found that, across the four countries, 19.9% of the population report chemical sensitivity, 7.4% report medically diagnosed MCS, 21.2% report either or both, and 32.2% report fragrance sensitivity. In addition, 26.0% of the population report asthma/asthma-like conditions, of which 42.6% report chemical sensitivity and 57.8% fragrance sensitivity. Also, 4.5% of the population report autism/ASDs, of which 60.6% report chemical sensitivity and 75.8% fragrance sensitivity. Among individuals with chemical sensitivity, 55.4% also report asthma/asthma-like conditions, 13.5% autism/ASDs, and 82.0% fragrance sensitivity. Although the prevalence of chemical sensitivity across the countries is statistically different, its co-prevalences with other conditions are statistically similar. Results also found that, for 44.1% of individuals with chemical sensitivity, the severity of health effects from fragranced products can be potentially disabling. Further, 28.6% of those with chemical sensitivity have lost workdays or a job, in the past year, due to exposure to fragranced products in the workplace. Results indicate that chemical sensitivity is widespread across the four countries, affecting over 61 million people, that vulnerable individuals such as those with asthma and autism are especially affected, and that fragranced consumer products can contribute to the adverse health, economic, and societal effects.
|Evaluation of particulate matter deposition in the human respiratory tract during winter in Nanjing using size and chemically resolved ambient measurements|
Size-segregated ambient aerosols were collected by a five-stage impactor at a suburban Nanjing site during the winter of 2016–2017 to estimate the chemical composition and size distribution of particles deposited in different parts of the human respiratory tract. Chemical compositions of carbonaceous aerosols, water-soluble ions, and trace heavy metals were measured. Particulate matter (PM) mass deposited in nasopharyngeal (NOPL), tracheobronchial (TB), and pulmonary (P) was obtained by integrating the size-dependent deposition fractions. During the sampling period, the average PM10 and PM2.5 concentrations were 108.8 ± 30.8 and 77.2 ± 24.2 μg/m3, respectively. Organic matter and water-soluble ions were major components in fine particles. The fine particles had a significant contribution to the particulate pollution in winter Nanjing. The mass concentration of particles increases significantly from the clean days to the pollution days, especially for particles in 1–2.5 μm. The proportion of NO3− and undetected components in particulate matter increases on pollution days, while the proportion of elemental carbon (EC), SO42−, and NH4+ decreases. During the study period, the total particulate matter deposit per minute in the NOPL, TB, and P was 1.06 ± 0.35, 0.10 ± 0.03, and 0.42 ± 0.14 μg, respectively, assuming normal respiration of tidal volumes of 1450 cm3 per breath and 15 breaths per minute. Particles in 2.5–10 μm had the highest deposition mass in NOPL of 0.57 ± 0.16 μg, while particles in < 0.5 μm had the highest deposition mass in TB (0.03 ± 0.01 μg), and particles in 1–2.5 μm had the highest deposition mass in P (0.14 ± 0.06 μg). The total particulate matter deposited in the NOPL, TB, and P increased from 0.79 ± 0.25, 0.08 ± 0.02, and 0.30 ± 0.09 μg on the clean days to 1.23 ± 0.29 μg, 0.12 ± 0.03 μg, and 0.49 ± 0.11 μg on the pollution days. More secondary inorganic aerosol (SNA) and metals (especially Zn, Cr, and Cu) were in the PM deposited in TB and P than in the ambient PM, while more undetected components in the PM deposited in NOPL. The chemical composition fractions deposited in a specific region were different from those measured in the ambient atmosphere, indicating that health effect studies of PM should consider the deposition rates of PM in the human respiratory tract, in addition to the ambient size and chemical characteristics of ambient PM.
|Measuring the value of airborne particulate matter reduction in Seoul|
Airborne suspended particles, also generally referred to as fine dust, are one of Korea's most serious environmental and economic concerns. This paper estimates the perceived cost of damage from fine dust in the housing market in Seoul. To do this, we collected data on approximately 120,000 apartment transactions in 2016 and created variables explaining the apartment price, including the concentration of fine dust at the district level. Our results indicate that price premiums exist for apartments in areas with fine dust concentration decrease. This finding reflects the willingness to pay for reductions in fine dust levels, which can be viewed as the monetary value of the benefit with respect to a cost-benefit analysis for fine dust reduction policies. This finding might also provide valuable information when making decisions on the degree of effort that our society must make, and the resources needed, to mitigate this problem.
|Temperature, temperature extremes, and cause-specific respiratory mortality in China: a multi-city time series analysis|
Chronic respiratory diseases cause huge death burden worldwide, especially in developing countries. The influence of ambient temperature on respiratory mortality has attracted growing concerns in the background of climate change. Daily cause-specific respiratory deaths and meteorological variables were collected from 16 Chinese cities during 2007–2013. We first applied the distributed lag non-linear model for each city to calculate the percentage change in respiratory mortality risk with a 1 °C change in moderate and extreme temperature range. Then, random-effect meta-analytical approach was used to produce the pooled effects. Individual-level and city-level effect modifications were separately assessed by the stratified analysis and mixed effects meta-regression model. Both cold and heat effects were associated with respiratory mortality. The pooled excess risk was 4.40% (95%CI: 2.75–6.08%), 2.23% (1.19–3.28%), 2.64% (1.81–3.47%), and 4.21% (3.10–5.33%) for 1 °C change among extreme cold, moderate cold, moderate heat, and extreme heat, respectively. Positive heat and cold effects were found for COPD, asthma, and pneumonia, among which asthma was most vulnerable to extreme cold temperatures, with the effect estimate of 6.52% (2.73–10.46%). The heat effects were much higher in females than males. Slightly higher risks were also observed in the elderly during the heat, and those with lower education level during the heat and extreme cold. City-level modifiers included green coverage rates and diurnal temperature range. Ambient heat and cold temperatures are positively associated with respiratory mortality in China. Individual and city-specific effect modifiers should be taken into consideration in policy-making.
|The effect of short-term exposure to O 3 , NO 2 , and their combined oxidative potential on mortality in Rome|
There is large epidemiological evidence on the short-term health effects of O3 and NO2. These gaseous pollutants induce oxidative stress through their oxidative potential. Therefore, the evaluation of their combined oxidative capacity (Ox) has been proposed rather than studying the effect of either gas individually. To study the short-term effects of daily concentrations of O3, NO2, and Ox on mortality in Rome, in 2002–2015, daily deaths from the city mortality registry were analyzed along with O3 and NO2 levels observed in Rome and with estimated Ox and Owt (Ox, weighted by the redox potential of O3 and NO2). A Poisson regression model was used considering trends, and meteorological and population changes. The effects on mortality were estimated at lag 0–1 and 0–5 for 10 μg/m3. O3 and NO2 were associated with mortality, with the highest effects at lag 0–5, 0.81% (0.45–1.17) and 2.72% (2.07–3.37), respectively. Ox had an intermediate effect between the two gases. After adjusting for PM10, Owt had a stronger effect (1.72%; 1.14–2.30) than either gas, 0.86% (0.50–1.22) for O3 and 1.61% (1.15–2.06) for NO2. Both Ox and Owt were associated with cerebrovascular, respiratory and, to a lesser extent, cardiac mortality more than either gas. These results suggest that the use of Ox (or Owt) can provide a better assessment of the combined role of O3 and NO2 on mortality and can avoid the uncertainty of the threshold level for ozone. The brain and lungs seem to be the main targets of O3 and NO2.
|Artificial turf: chemical flux and development of silicone wristband partitioning coefficients|
This work uses passive samplers to identify PAHs and OPAHs not previously associated with artificial turf, and to provide the first quantitative measure of in situ flux of semi-volatile contaminants on artificial turf fields. Both air (1.5-m height) and turf air (immediately above turf surface) were sampled using two sampling materials: low-density polyethylene and silicone. Utilizing a broad targeted screen, we assess both artificial turf and samples of crumb rubber for over 1530 chemicals including pesticides, phthalates, and personal care products. We report the presence of 25 chemicals that have not yet been reported in artificial turf literature, including some with known human effects. The samplers were also quantitatively analyzed for polycyclic aromatic hydrocarbons yielding gas-phase concentrations at breathing height and surface level—the first such report on an artificial turf outdoor field. Turf pore-air and air chemicals were highly correlated at all sites, and particularly at the recently installed indoor site. Flux of chemicals between air and turf surface appear to follow field age although more research is needed to confirm this trend. The thermal extraction process and silicone passive samplers used are suitable for larger-scale environmental sampling campaigns that aim for less solvent and sample processing. By co-deploying silicone passive samplers and conventional low-density polyethylene, partitioning coefficients are derived that can be used for future silicone passive air sampling environmental assessment. This study provides an initial demonstration that passive samplers can be used to quantify volatile and semi-volatile organic chemicals from artificial turf.
|Long-range transported biomass-burning aerosols from large-scale wildfires in Russia and surrounding regions with respect to radioactive tracers|
Biomass burning caused by anthropogenic activity such as agriculture-burning periods (common practice during harvesting, post-harvesting, or preplanting) or naturally occurring forest fires, and domestic biofuel combustion is a frequent phenomenon causing global concern. Agricultural burning, although restricted in some countries, significantly contributes to regional air-quality deterioration and national emissions. This work focuses on atmospheric measurements at the suburbs of Athens, on August 2010, during extensive forest fires in the European Russian central plains. The effect of these fires on the measured concentrations of specific radioactive isotopes and biomass-burning tracers was studied, for long-range transport of aerosols from Russian plains. Mean total beta radioactivity was found more than 2.5 times higher during the incident compared to background values. High values were also reported for the isotope 40K, and its fluctuations were following the course of the event. 7Be showed no significant difference between the two periods, which is expected due to its origin. During the event 234Th (238U), activity concentrations were also detected. Their fluctuations showed no significant correlation with the course of the event. The average values during the period before and right after the incident is for organic carbon 2.74 μg/m3, elemental carbon 1.53 μg/m3, and for carbonate carbon 0.16 μg/m3. During the incident, the highest values were observed on August 18, with concentrations for organic carbon 5.49 μg/m3, elemental carbon 0.64 μg/m3, and carbonate carbon 0.32 μg/m3. This fact may be considered as an indicator of biomass-burning incident during the period 12–19 August 2010.