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。     

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.     

A new dose model for assessment of health risk due to contaminants in air

The problem of making quantitative assessments of the risks associated with human exposure to toxic contaminants in the environment is a pressing one. This study demonstrates the capability of a new computational technique involving the use of fuzzy logic and neural networks to produce realistic risk assessments. The systematic analysis of human exposure involves the use of measurements and models, the results of which are sometimes used in regulatory decisions or in the drafting of legislation. Because of limited scientific understanding, however, interpretation of models often involves substantial uncertainty. Extensive measurement programs can be very expensive. The high complexity and inherent heterogeneity of exposure analysis is still a major challenge. The approach to this challenge tested here is to use a new model incorporating sophisticated artificial intelligence algorithms. Exposure assessment often requires that a number of factors be evaluated, including exposure concentrations, intake rates, exposure times, and frequencies. These factors are incorporated into a system that can "learn" the relevant relationships based on a known data set. The results can then be applied to new data sets and thus be applied widely without the need for extensive measurements. In this analysis, an example is developed for human health risk through inhalation exposure to benzene from vehicular emissions in the cities of Auckland and Christchurch, New Zealand. Risk factors considered were inhaled contaminant concentration, age, body weight, and activity patterns of humans. Three major variables affecting the inhaled contaminant concentration were emissions (mainly from motor vehicles), meteorology (wind speed, temperature, and atmospheric stability), and site factors (hilly, flat, etc.). The results are preliminary and used principally to demonstrate the technique, but they are very encouraging.     

Quantitative cancer risk assessment and local mortality burden for ambient air pollution in an eastern Mediterranean City

Health risks posed by ambient air pollutants to the urban Lebanese population have not been well characterized. The aim of this study is to assess cancer risk and mortality burden of non-methane hydrocarbons (NMHCs) and particulates (PM) based on two field-sampling campaigns conducted during summer and winter seasons in Beirut. Seventy NMHCs were analyzed by TD-GC-FID. PM_2.5 elemental carbon (EC) components were examined using a Lab OC-EC aerosol Analyzer, and polycyclic aromatic hydrocarbons were analyzed by GC-MS. The US EPA fraction-based approach was used to assess non-cancer hazard and cancer risk for the hydrocarbon mixture, and the UK Committee on Medical Effects of Air Pollutants (COMEAP) guidelines were followed to determine the PM_2.5 attributable mortality burden. The average cumulative cancer risk exceeded the US EPA acceptable level (10⁻⁶) by 40-fold in the summer and 30-fold in the winter. Benzene was found to be the highest contributor to cancer risk (39–43%), followed by 1,3-butadiene (25–29%), both originating from traffic gasoline evaporation and combustion. The EC attributable average mortality fraction was 7.8–10%, while the average attributable number of deaths (AD) and years of life lost (YLL) were found to be 257–327 and 3086–3923, respectively. Our findings provide a baseline for future air monitoring programs, and for interventions aiming at reducing cancer risk in this population.

     

Phytotoxic risk assessment of ambient air pollution on agricultural crops in Selangor State, Malaysia

The phytotoxic risk of ambient air pollution to local vegetation was assessed in Selangor State, Malaysia. The AOT40 value was calculated by means of the continuously monitored daily maximum concentration and the local diurnal pattern of O3. Together with minor risks associated with the levels of NO2 and SO2, the study found that the monthly AOT40 values in these peri-urban sites were consistently over 1.0 ppm.h, which is well in exceedance of the given European critical level. Linking the O3 level to actual agricultural crop production in Selangor State also indicated that the extent of yield losses could have ranged from 1.6 to 5.0% (by weight) in 2000. Despite a number of uncertainties, the study showed a simple but useful methodological framework for phytotoxic risk assessment with a limited data set, which could contribute to appropriate policy discussion and countermeasures in countries under similar conditions.     

The current practice of health risk assessment: potential impact on standards for toxic air contaminants

Since the Bhopal incident, the public has placed pressure on regulatory agencies to set community exposure limits for the dozens of chemicals that may be released by manufacturing facilities. More or less objective limits can be established for the vast majority of these chemicals through the use of risk assessment. However, each step of the risk assessment process (i.e., hazard identification, dose-response assessment, exposure assessment, and risk characterization) contains a number of pitfalls that scientists need to avoid to ensure that valid limits are established. For example, in the hazard identification step there has been little discrimination among animal carcinogens with respect to mechanism of action or the epidemiology experience. In the dose-response portion, rarely is the range of "plausible" estimated risks presented. Physiologically based pharmacokinetic (PB-PK) models should be used to understand the difference between the tissue doses and the administered dose, as well as the difference in target tissue concentrations of the toxicant between rodents and humans. Biologically-based models like the Moolgavkar-Knudson-Venzon (MKV) should be developed and used, when appropriate. The exposure assessment step can be significantly improved by using more sensitive and specific sampling and analytical methods, more accurate exposure parameters, and computer models that can account for complex environmental factors. Whenever possible, model predictions of exposure and uptake should be validated by biological monitoring of exposed persons (urine, blood, adipose) or by field measurements of plants, soil, fish, air, or water. In each portion of an assessment, the weight of evidence approach should be used to identify the most defensible value. In the risk characterization, the best estimate of the potential risk as well as the highest plausible risk should be presented. Future assessments would be much improved if quantitative uncertainty analyses were conducted. Procedures are currently available for making future assessments. By correcting some of these shortcomings in how health risk assessments have been conducted, scientists and risk managers should be better able to identify scientifically appropriate ambient air standards and emission limits.     

A Gaussian puff model with optimal interpolation for air pollution modelling assessment

A Gaussian plume model was modified to simulate the dispersion of non-reactive air pollutants under non-homogeneous wind conditions through a multi-puff approach. It was applied to the city of Lisbon and evaluated by comparison with measured sulphur dioxide data, showing a reasonable skill to estimate the transport and dispersion of pollutants under complex wind field and different atmospheric conditions. The modelling results were integrated with observed data, based on correlation functions determined from historical values, to obtain the improved analytical results by using optimal interpolation. A significant improvement over the predictions by the Gaussian puff model alone was achieved.     

西安市大气中多环芳烃的季节变化及健康风险评价

对西安市2009年6月-2010年5月空气中的总悬浮颗粒（TSP）和气态样品进行了连续采样,利用GC—MS对16种PAHs进行分析。∑PAHs浓度（气相＋颗粒相）范围为39．93～1032．46ng／m^3,平均值为197．34ng／m^3;其中,冬季大气中∑PAHs浓度最大,相对浓度的范围为31．21％～72．98％,而夏季的浓度最小;检测出16种2～6环的PAHs,其中以3—4环为主。利用特征分子比值法和因子分析进行源解析,发现研究区PAHs的主要来源为燃煤和机动车尾气排放。通过苯并（a）芘（BaP）等效毒性（BEQ）和苯并（a）芘等效致癌浓度（BaPE）进行健康风险评价,结果显示,西安大气中PAHs的毒性具有明显的季节差异,特别是秋季和冬季大气中PAHs对人类的健康存在较大的潜在威胁。     

Human health risks in megacities due to air pollution

This study evaluates the health risks in megacities in terms of mortality and morbidity due to air pollution. A new spreadsheet model, Risk of Mortality/Morbidity due to Air Pollution (Ri-MAP), is used to estimate the excess numbers of deaths and illnesses. By adopting the World Health Organization (WHO) guideline concentrations for the air pollutants SO₂, NO₂ and total suspended particles (TSP), concentration-response relationships and a population attributable-risk proportion concept are employed. Results suggest that some megacities like Los Angeles, New York, Osaka Kobe, Sao Paulo and Tokyo have very low excess cases in total mortality from these pollutants. In contrast, the approximate numbers of cases is highest in Karachi (15,000/yr) characterized by a very high concentration of total TSP (～670 μg m^?3). Dhaka (7000/yr), Beijing (5500/yr), Karachi (5200/yr), Cairo (5000/yr) and Delhi (3500/yr) rank highest with cardiovascular mortality. The morbidity (hospital admissions) due to Chronic Obstructive Pulmonary Disease (COPD) follows the tendency of cardiovascular mortality. Dhaka and Karachi lead the rankings, having about 2100/yr excess cases, while Osaka-Kobe (～20/yr) and Sao Paulo (～50/yr) are at the low end of all megacities considered. Since air pollution is increasing in many megacities, and our database of measured pollutants is limited to the period up to 2000 and does not include all relevant components (e.g. O₃), these numbers should be interpreted as lower limits. South Asian megacities most urgently need improvement of air quality to prevent excess mortality and morbidity due to exceptionally high levels of air pollution. The risk estimates obtained from Ri-MAP present a realistic baseline evaluation for the consequences of ambient air pollution in comparison to simple air quality indices, and can be expanded and improved in parallel with the development of air pollution monitoring networks.     

汽车内空气甲醛污染状况及其影响因素分析

为了解车内空气甲醛污染状况及其影响因素,随机测定200辆私家轿车车内空气甲醛浓度、温度和湿度,同时通过问卷调查获得车型、车龄、车内装饰物和关窗时间等基本情况.检测可知,车内空气甲醛几何均数为0.030 mg/m 3 ,95%可信区间为0.027～0.033 mg/m 3 .参照《室内空气质量标准》(GB/T 18883-2002)规定为0.100 mg/m 3 ,超标率为1.5%.车内空气甲醛对数质量浓度(y)与车龄(X 1 )、车内温度(X 2 )、汽车档次(X 3 )、车内温度×关窗时间(X 4 )有关,回归方程为y=-2.088 5-0.096 6X 1 0.019 9X2 0.049 5X 3 0.002 2X 4 .表明车内甲醛污染主要存在于车龄不足半年、关窗时间超过3 h以上的车辆,降低车内温度可有效控制车内甲醛污染.     

Quantitative assessment of Chicago air pollution through analysis of covariance

A covariance analysis of source-receptor relationships is reported based on a 6-month air-pollution monitoring study in Chicago. Regular simultaneous measurements were made of total and respirable particulate matter (dp, particle diameter, < 2 μm); sulfate, nitrate and 18 elemental compositions for both size ranges; electrical aerosol analyzer size distributions; condensation nuclei counts; light scatter; CO, SO₂, NO, NO₂ and O₃; temperature, u.v. radiation, rainfall, humidity and wind speed and direction.The ratio between light scatter and respirable particle concentration was 2.72 m²g⁻¹ which agrees well with ratios measured at a variety of other locations. Analysis of covariance by wind direction found enrichment, with respect to TSP, for Fe, V, As and NO⁻₃. The patterns were consistent with existing point source locations and strengths. The effect of street salting was also evident as Na was enriched with respect to the winter season for dp > 2 μm. On days of low humidity (< 8 mm Hg) SO²⁻₄ concentrations were linearly associated with SO₂ levels (r² = 0.72). This relationship probably reflects primary source contributions, defined as sulfate directly emitted or formed relatively soon after discharge. At higher humidities the SO₂–SO²⁻₄ relationship was not linear; and secondary contributions, as reflected in ozone concentrations from preceding days, appeared to be important. The average primary source contribution to SO²⁻₄ concentration was estimated at 5.5 μg m⁻³ which represented about 60 % of the average level. An analysis of nitrate—NO₂ concentrations suggested a linear relationship (r² = 0.58).Analysis of covariance was found to better discriminate between source categories responsible for differences in particulate matter components than the more commonly used analysis of variance and linear regression techniques.     

洋河流域不同时空水体重金属污染及健康风险评价

确定水体重金属污染及健康风险时空变化趋势,对流域水环境管理具有重要指导意义。基于1995年、2005年和2015年洋河流域10个监测断面的重金属监测数据,采用健康风险评价模型,对洋河流域As、Cd、Pb、Hg 和 Cu 的浓度及其引起健康风险的时空变化进行了评价。结果表明,洋河流域重金属污染及其健康风险在时间上呈降低趋势,超过地表水质量标准三类标准的重金属由1995年的Cd、Pb和Hg变为2005年和2015年的Cd、Pb。致癌物质As和Cd所引起的个人年均风险远远高于非致癌物质 Pb、Hg 和 Cu。重金属健康风险总和在1995年所有监测断面均超过国际辐射防护委员会（ICRP）推荐的最大可接受风险水平,2005年全部在最大可接受风险水平以下,2015年只有响水铺略微高于该水平。在空间分布上,重金属污染较为严重及其健康风险较大的区域集中于南洋河下游城区段、清水河下游张家口市区段和洋河干流下游段。     

Engineering risk assessment for emergency disposal projects of sudden water pollution incidents

Without an engineering risk assessment for emergency disposal in response to sudden water pollution incidents, responders are prone to be challenged during emergency decision making. To address this gap, the concept and framework of emergency disposal engineering risks are reported in this paper. The proposed risk index system covers three stages consistent with the progress of an emergency disposal project. Fuzzy fault tree analysis (FFTA), a logical and diagrammatic method, was developed to evaluate the potential failure during the process of emergency disposal. The probability of basic events and their combination, which caused the failure of an emergency disposal project, were calculated based on the case of an emergency disposal project of an aniline pollution incident in the Zhuozhang River, Changzhi, China, in 2014. The critical events that can cause the occurrence of a top event (TE) were identified according to their contribution. Finally, advices on how to take measures using limited resources to prevent the failure of a TE are given according to the quantified results of risk magnitude. The proposed approach could be a potential useful safeguard for the implementation of an emergency disposal project during the process of emergency response.

     

Short-term effects and economic burden assessment of ambient air pollution on hospitalizations for schizophrenia

Environmental Science and Pollution Research - The evidence&nbsp;on the health and economic impacts of air pollution with schizophrenia is scarce, especially in developing countries. In this...     

Ambient air concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans in Ohio: Sources and health risk assessment

PCDD and PCDF were measured in air samples collected in Ohio in 1987. No 2,3,7,8-TCDD was detected in any of the samples with a detection limits of less than 240 fg/m³. Using a chemical mass balance model applied to PCDD/PCDF congener group profiles, major potential sources of these compounds to the atmosphere in Ohio were determined to be municipal solid waste combustion, and sewage sludge combustion. Cancer risk calculations for inhalation of PCDD/PCDF in ambient air in Ohio are approximately 10–6. Given the current knowledge of the health effects of exposure to PCDD/PCDF in air, there is no appreciable risk to public health for the levels of these compounds found in ambient air in Ohio.     

Modeling traffic air pollution in street canyons in New York City for intra-urban exposure assessment in the US Multi-Ethnic Study of atherosclerosis and air pollution

We evaluated the Danish AirGIS air quality and exposure model system using air quality measurement data from New York City in the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air). Measurements were used from three US EPA Air Quality System (AQS) monitoring stations and a comprehensive MESA Air measurement campaign including about 150 different locations and about 650 samples of about 2 week measurements of NO_x, NO₂ and PM_2.5. AirGIS is a deterministic exposure model system based on the dispersion models Operational Street Pollution Model (OSPM) and the Urban Background Model (UBM). The UBM model reproduced the annual levels within 1–26% depending on station and pollutant at the three urban background EPA monitor stations, and generally reproduced well the seasonal and diurnal variation. The full model with OSPM and UBM reproduced the MESA Air measurements with a correlation coefficient of r² = 0.51 for NO_x, r² = 0.28 for NO₂ and r² = 0.73 for PM_2.5.     

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.