Local Arctic air pollution: Sources and impacts

Local emissions of Arctic air pollutants and their impacts on climate, ecosystems and health are poorly understood. Future increases due to Arctic warming or economic drivers may put additional pressures on the fragile Arctic environment already affected by mid-latitude air pollution. Aircraft data were collected, for the first time, downwind of shipping and petroleum extraction facilities in the European Arctic. Data analysis reveals discrepancies compared to commonly used emission inventories, highlighting missing emissions (e.g. drilling rigs) and the intermittent nature of certain emissions (e.g. flaring, shipping). Present-day shipping/petroleum extraction emissions already appear to be impacting pollutant (ozone, aerosols) levels along the Norwegian coast and are estimated to cool and warm the Arctic climate, respectively. Future increases in shipping may lead to short-term (long-term) warming (cooling) due to reduced sulphur (CO₂) emissions, and be detrimental to regional air quality (ozone). Further quantification of local Arctic emission impacts is needed.     

Self-organized criticality of air pollution

In this work, we investigate the frequency-size distribution of three pollution indexes (PM₁₀, NO₂ and SO₂) in Shanghai. They are well approximated by power-law distributions, which suggest that air pollution might be a manifestation of self-organized criticality. We introduce a new numerical sandpile model with decay coefficient to reveal inherent dynamic mechanism of air pollution. Only changing the number value of decay coefficient of pollutants, this model gives a good simulation of three pollutants' statistical characteristic. This work shows that it is the self-organized criticality of the air pollutants that results in the temporal variation of air pollutant indexes and the minor air pollution sources can trigger the occurrence of large pollutant events by SOC behavior.     

空气污染暴露评价研究进展

介绍了暴露及暴露评价的基本概念、人体空气污染暴露评价的指示物及其特征,讨论暴露评价方法的类型,对各种方法的优、缺点进行了比较分析。根据综述和案例分析情况,对空气污染暴露评价研究的发展趋势进行了展望。     

Contemporary threats and air pollution

It is now well understood that air pollution produces significant adverse health effects in the general public and over the past 60 years, there have been on-going efforts to reduce the emitted pollutants and their resulting health effects. There are now shifting patterns of industrialization with many heavily polluting industries moving from developed countries with increasingly stringent air quality standards to the developing world. However, even in decreasing concentrations of pollutants, health effects remain important possibly as a result of changes in the nature of the pollutants as new chemicals are produced and as other causes of mortality and morbidity are reduced. In addition, there is now the potential for deliberate introduction of toxic air pollutants by local armed conflicts and terrorists. Thus, there are new challenges to understand the role of the atmospheric environment on public health in this time of changing economic and demographic conditions overlaid with the willingness to indirectly attack governments and other established entities through direct attacks on the general public.     

Assessment of air pollution impact

Several essential steps of air quality assessment are described, including identification, prediction, and evaluation of critical variables and potential changes of air quality. A coal-reconversion power plant in New York was selected as an example to illustrate the assessment.     

Forecasting air pollution potential: a synoptic climatological approach

This paper describes the development and application of an air pollution potential (APP) forecast model based on a synoptic climatological approach in a heavily industrialized area in Durban, South Africa. The aim of the forecasting procedure, based on a system of orange, red, and all-clear alerts, was to give industry advance warning of periods of poor atmospheric dispersion so that it could take action to reduce emissions. The key meteorological parameter in accurately identifying the commencement of an APP episode was found to be negative surface pressure tendency. Wind direction was the most useful parameter in estimating the end point of an APP episode. The model was very successful in identifying periods of elevated SO2, but there is a need for further refinement in forecasting the end point of an episode.     

Catalytic oxidation for air pollution control

Bench-scale experiments have been conducted to evaluate a series of titania-supported Pt-Pd (as oxides) catalysts in the presence and absence of MoO₃ and Fe₂O₃ additives for their effectiveness in the complete catalytic oxidation of volatile organic compounds (VOCs) in air likely to be found in waste gases. Under oxidizing conditions, all of the catalysts promoted the complete oxidation of VOCs to CO₂ and H₂O. 99 % Conversion was achieved with a C₂H₄-C₂H₆ gas mixture in air at temperatures between about 160–450 °C and at a space velocity of 20,000 h^?1. Oxidation activity for the titania supported catalysts were found to decrease in the order Pt-Pd-Mo-Fe > Pt-Pd-Mo > Pt-Pd-Fe > Pt-Pd. However, the addition of MoO₃ and Fe₂O₃ increase the catalyst activity and reduce the reaction temperature for the complete destruction. Ageing was also performed in order to study the stability of the most active catalyst. Pt-Pd-Mo-Fe (as oxides) on titania catalyst is effective in oxidizing a wide range of volatile organic compounds at relatively low temperatures (220–405 °C) and and at a space velocity of 40,000 h^?1 and is resistant to poisoning by halogenated and amine volatile organic compounds.     

Lichens as integrating air pollution monitors

In this work an attempt to combine the results of lichen mapping with the quantitative levels of certain trace elements in Hypogymnia physodes (L.) Nyl. collected on a national scale is presented. An Index of Atmospheric Purity (IAP) was calculated using a simple method of mapping lichens based on the assessment of the cover and frequency of crustose, foliose and fruticose lichens on different tree species. For determination of trace elements in lichens k0-instrumental neutron activation analysis was used. From the IAP results it can be concluded that the epiphytic lichen flora look quite poor with more than 70% of the territory in the fourth and third classes, which represent highly polluted and moderately polluted air. By comparing IAP results with elemental levels in H. physodes using multivariate statistical methods it was found that the elemental levels do not have a direct negative effect on the diversity of lichens but can help in identification of the type of possible pollution sources and their origin.     

Journey-time exposure to particulate air pollution

Journey-time exposures to particulate air pollution were investigated in Leicester, UK, between January and March 2005. Samples of TSP, PM₁₀, PM_2.5, and PM₁ were simultaneously collected using light scattering devices whilst journeys were made by walking an in-car. Over a period of two months, 33 pairs of walking and in-car measurements were collected along two circular routes. Average exposures while walking were seen to be higher than those found in-car for each of the particle fractions: average walking to in-car ratios were 1.2 (± 0.6), 1.5 (± 0.6), 1.3 (± 0.6), and 1.4 (± 0.6) μg m⁻³ for coarse (TSP–PM₁₀), intermediate (PM₁₀–PM_2.5), fine (PM_2.5–PM₁), and very fine particles (PM₁), respectively. Correlations between walking and in-car exposures were seen to be weak for coarse particles (r=0.10, p=0.58), moderate for the intermediate particles (r=0.49, p<0.01) but strong for fine (r=0.89, p<0.01) and very fine (r=0.90, P<0.01) particles. PM₁₀ exposures while walking were on average 70% higher than a nearby roadside fixed-site monitor whilst in-car exposures were 25% higher than the same fixed-site monitor. Particles with an aerodynamic diameter of less than 2.5 μm were seen to be highly correlated between walking and in-car particle exposures and a rural fixed-site monitor about 30 km south of Leicester.     

Evaluating sources of indoor air pollution

Evaluation of indoor air pollution problems requires an understanding of the relationship between sources, air movement, and outdoor air exchange. Research is underway to investigate these relationships. A three-phase program is being implemented: 1) Environmental chambers are used to provide source emission factors for specific indoor pollutants; 2) An IAQ (Indoor Air Quality) model has been developed to calculate indoor pollutant concentrations based on chamber emissions data and the air exchange and air movement within the indoor environment; and 3) An IAQ test house is used to conduct experiments to evaluate the model results. Examples are provided to show how this coordinated approach can be used to evaluate specific sources of indoor air pollution. Two sources are examined: 1) para-dichlorobenzene emissions from solid moth repellant; and 2) particle emissions from unvented kerosene heaters. The evaluation process for both sources followed the three-phase approach discussed above. Para-dichlorobenzene emission factors were determined by small chamber testing at EPA's Air and Energy Engineering Research Laboratory. Particle emission factors for the kerosene heaters were developed in large chambers at the J. B. Pierce Foundation Laboratory. Both sources were subsequently evaluated in EPA's IAQ test house. The IAQ model predictions showed good agreement with the test house measurements when appropriate values were provided for source emissions, outside air exchange, in-house air movement, and deposition on "sink" surfaces.     

Human health effects of air pollution

Hazardous chemicals escape to the environment by a number of natural and/or anthropogenic activities and may cause adverse effects on human health and the environment. Increased combustion of fossil fuels in the last century is responsible for the progressive change in the atmospheric composition. Air pollutants, such as carbon monoxide (CO), sulfur dioxide (SO(2)), nitrogen oxides (NOx), volatile organic compounds (VOCs), ozone (O(3)), heavy metals, and respirable particulate matter (PM2.5 and PM10), differ in their chemical composition, reaction properties, emission, time of disintegration and ability to diffuse in long or short distances. Air pollution has both acute and chronic effects on human health, affecting a number of different systems and organs. It ranges from minor upper respiratory irritation to chronic respiratory and heart disease, lung cancer, acute respiratory infections in children and chronic bronchitis in adults, aggravating pre-existing heart and lung disease, or asthmatic attacks. In addition, short- and long-term exposures have also been linked with premature mortality and reduced life expectancy. These effects of air pollutants on human health and their mechanism of action are briefly discussed.     

Planetary-wave behavior and Arctic air pollution

An attempt has been made to relate episodes of air pollution at Barrow, Alaska, containing vanadium, to the behavior of planetary waves in middle and high latitudes. A stationarity index for planetary waves is defined as the ratio between amplitudes computed from monthly mean maps and the mean amplitudes computed on a daily basis and averaged over the same month, irrespective of phase angle. Longitude-time sections of 500 mb height anomalies at various latitudes are related to vanadium pollution episodes at Barrow.