A review of traffic-related air pollution exposure assessment studies in the developing world

Exposure assessment studies in the developing world are important. Although recent years have seen an increasing number of traffic-related pollution exposure studies, exposure assessment data on this topic are still limited. Differences among measuring methods and a lack of strict quality control in carrying out exposure assessment make it difficult to generalize and compare findings between studies. In this article, exposure assessment studies carried out in the developing world on several traffic-related air pollutants are reviewed. These pollutants include particulate matter (PM), carbon monoxide (CO), nitrogen dioxide (NO(2)), volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs). In addition, it discusses advantages and disadvantages of various monitoring methods (ambient fixed-site monitoring, microenvironment monitoring, and personal exposure assessment using portable samplers) for these pollutants in exposure assessment studies. Also included in this paper is a brief introduction of standards for these pollutants in ambient air or in occupational settings established by the United States Environmental Protection Agency (USEPA), the United States Occupational Safety and Health Administration (OSHA) and the World Health Organization (WHO). The review ends with a summary of the limitations and gaps in recent studies and suggestions for future research in the developing world.     

The relationship between socio-economic indicators and air pollution in England and Wales: implications for environmental justice

This paper investigates the distribution of three common air pollutants, sulphur dioxide, nitrogen dioxide and fine particulates (PM₁₀), in England and Wales with respect to social class, ethnicity and population density. A multilevel model is used to demonstrate regional differences in the social distribution of pollution. The results show that, allowing for ethnicity and population density, there are different relationships between socio-economic status and exposure to air pollution within different regions in England and Wales. These differences suggest that national legislation introduced to reduce air pollution levels may give rise to environmental injustice, with geographical and social differences in the costs and benefits arising to the population due to such legislation. Received: 24 February 1999 / Accepted: 2 September 1999     

Characterizing multi-pollutant air pollution in China: Comparison of three air quality indices

Multi-pollutant air pollution (i.e., several pollutants reaching very high concentrations simultaneously) frequently occurs in many regions across China. Air quality index (AQI) is used worldwide to inform the public about levels of air pollution and associated health risks. The current AQI approach used in China is based on the maximum value of individual pollutants, and does not consider the combined health effects of exposure to multiple pollutants. In this study, two novel alternative indices – aggregate air quality index (AAQI) and health-risk based air quality index (HAQI) – were calculated based on data collected in six megacities of China (Beijing, Shanghai, Guangzhou, Shjiazhuang, Xi'an, and Wuhan) during 2013 to 2014. Both AAQI and HAQI take into account the combined health effects of various pollutants, and the HAQI considers the exposure (or concentration)-response relationships of pollutants. AAQI and HAQI were compared to AQI to examine the effectiveness of the current AQI in characterizing multi-pollutant air pollution in China. The AAQI and HAQI values are higher than the AQI on days when two or more pollutants simultaneously exceed the Chinese Ambient Air Quality Standards (CAAQS) 24-hour Grade II standards. The results of the comparison of the classification of risk categories based on the three indices indicate that the current AQI approach underestimates the severity of health risk associated with exposure to multi-pollutant air pollution. For the AQI-based risk category of ‘unhealthy’, 96% and 80% of the days would be ‘very unhealthy’ or ‘hazardous’ if based on AAQI and HAQI, respectively; and for the AQI-based risk category of ‘very unhealthy’, 67% and 75% of the days would be ‘hazardous’ if based on AAQI and HAQI, respectively. The results suggest that the general public, especially sensitive population groups such as children and the elderly, should take more stringent actions than those currently suggested based on the AQI approach during high air pollution events. Sensitivity studies were conducted to examine the assumptions used in the AAQI and HAQI approaches. Results show that AAQI is sensitive to the choice of pollutant irrelevant constant. HAQI is sensitive to the choice of both threshold values and pollutants included in total risk calculation.     

空气污染、空间外溢与公共健康——以中国珠江三角洲9个城市为例

空气污染对居民公共健康的影响,引起了人们高度的关注。但大多数学者研究从样本的独立性出发且不考虑内生性问题,忽视区域之间空间相关性,所得结论和政策建议需谨慎对待。为了弥补上述不足,本文基于Grossman中国宏观健康生产函数,选取2001—2014年中国广东省珠江三角洲9个城市作为样本,选择以PM_(10)和PM_(2.5)作为空气污染的代理指标,在充分考虑空间效应和严格假设检验的基础上选择合适的空间计量经济学模型,对此进行实证研究。主要研究结果显示:空气污染对居民的公共健康带来了负面影响,即PM_(10)和PM_(2.5)每增加1%,导致哮喘疾病和内科门诊等疾病人数不断上升,且影响都比较大,尤其是对哮喘疾病的影响分别为0.2236%和0.2272%。经济增长对公共健康均有显著的促进作用,影响最大;其它财政医疗支出、卫生技术人员和人口密度等要素对居民公共健康的影响较小。由于空气污染的负外部性,研究还发现,区域之间空气污染的"溢出效应"对领域居民公共健康存在显著的影响,说明忽视空间自相关性的存在,会使得空气污染对公众健康的估计产生偏差。从长期看,空气污染对本地居民公共健康的直接效应都显著为正,PM_(2.5)间接效应显著为负,但PM_(10)间接效应并不显著。因此,各级政府除了在源头上治理污染物的排放,提高公共健康水平外,还应该打破各自为阵的行政垄断,应该作为一个整体,实现跨区域环保合作,共同治理和制定公共卫生政策等。这对区域之间协同减排和保护居民公共健康具有重要的理论和现实意义。     

Connecting the Dots: Public Engagement with Environmental Data

Air pollution and other environmental hazards are often imperceptible and need to be made publicly visible. The paper argues for the importance of visualizations in drawing public attention to imperceptible hazards and in providing the public with access to empirical data describing the risks. It also argues for critical inquiry into hazards’ selective visibility as it is produced by visualizations. The impact of visualizations and their selective visibility are considered through the example of a public art project called Particle Falls installed in 2014 in Pittsburgh, a city with a long history of both ignoring air pollution and working to ameliorate this problem. I examine the impact and selective visibility of Particle Falls by considering the underlying production of data, as well as context and support systems for this visualization, and by comparing it with other visualizations of local air quality.     

美国跨界大气环境监管经验对中国的借鉴

大气污染因其污染因子易受气候变化等影响,可进行长距离跨界传输,是典型的跨行政边界问题。我国地域辽阔,行政区域众多且与多个国家接壤或比邻,跨界污染问题研究十分必要。近年来,我国区域性大气污染问题明显,管理手段落后,缺乏相应管理体制和机制。美国在跨界大气环境管理方面取得了显著的成果,积累了丰富的经验,这对我国大气环境管理,尤其是跨界大气环境管理工作具有重要的借鉴意义。本文首先以美国大气跨界污染治理为例,结合具体实例,主要从机构设置、职能职责、运作方式三个方面详细分析了州内、州与州与之间以及跨国界三个层次跨界大气环境监管体系;其次,从上述几方面对我国与美国跨区域大气环境监管机制进行逐项比较分析;再次,对我国跨区域大气环境监管体系障碍分析认为,统分结合的环境管理体制和尚未建立区域联防联控机制是借鉴发达国家跨界大气环境监管经验的主要障碍;在此基础上,针对我国的跨区域大气环境管理工作提出5个方面的建议,即成立跨区域的权力机构;加强政府区域间协调合作;强化依法治理;多种管理手段综合应用;加强信息公开和公众参与。     

Using city-wide mobile noise assessments to estimate bicycle trip annual exposure to Black Carbon

Several studies have shown that a significant amount of daily air pollution exposure, in particular Black Carbon (BC), is inhaled during bicycle trips. Previously, the instantaneous BC exposure of cyclists was modeled as the sum of a background concentration and a local traffic related component based on a local assessment of traffic noise. We present a fast and low cost methodology to achieve a city-wide assessment of yearly average BC exposure of cyclists along their trips, based on a city-wide mobile noise sensing campaign.The methodology requires participatory sensing measurements of noise, partially combined with BC and/or other air pollutants sensitive to local traffic variations. The combined measurements cover the spatial and meteorological variability and provide the data for an instantaneous exposure model. The mobile noise-only measurements map the full city; and yearly meteorology statistics are used to extrapolate the instantaneous exposure model to a yearly average map of in-traffic air pollution exposure. Less than four passages at each segment along the network with mobile noise equipment are necessary to reach a standard error of 500 ng/m³ for the yearly average BC exposure.A strong seasonal effect due to the BC background concentration is detected. The background contributes only 25% to the total trip exposure during spring and summer. During winter the background component increases to 50–60%. Engine related traffic noise along the bicyclist's route is a valid indicator of the BC exposure along the route, independent of the seasonal background. Low exposure route selection results in an exposure reduction of 35% in winter and 60% in summer, sensitive to the weather conditions, specific trip attributes and the available alternatives.The methodology is relevant for further research into the local effects of air pollution on health. Mobile noise mapping adds local traffic data including traffic dynamics into the air pollution exposure assessments. Local policy makers and urban planners can use the results to support the implementation of low exposure infrastructure, create awareness through route planners and achieve behavioral changes toward active travel modes.     

Concentrations and determinants of outdoor, indoor and personal nitrogen dioxide in pregnant women from two Spanish birth cohorts

Determinants of outdoor, indoor and personal concentrations of nitrogen dioxide (NO₂) were assessed in a subset of pregnant women of the Spanish INMA (Environment and Childhood) Study. Home indoor and outdoor NO₂ concentrations were measured during 48 h with passive samplers for 50 and 58 women from the INMA cohorts of Valencia and Sabadell, respectively. Women from Sabadell also carried personal NO₂ samplers during the same period. Data on time–activity patterns, socio-economic characteristics, and environmental exposures were obtained through questionnaires. Multiple linear regression models were developed to predict NO₂ levels.In Valencia, median outdoor NO₂ levels (42 µg/m³) were higher than median indoor levels (36 µg/m³). In Sabadell, personal NO₂ showed the highest median levels (40 µg/m³), followed by indoor (32 µg/m³) and outdoor (29 µg/m³) levels. Personal exposure to NO₂ correlated best with the indoor NO₂ levels. Temporal and traffic-related variables were significant predictors for outdoor NO₂ levels. Thirty-two percent of the indoor NO₂ variability in the two cohorts was explained by outdoor NO₂ levels and the use of the gas appliances. The model for personal exposure accounted for 59% of the variance in NO₂ levels in Sabadell with four predictor variables (outdoor and indoor NO₂ levels, time spent in outdoor environments and time exposed to a gas cooker). No significant association was found between personal or indoor NO₂ levels and exposure to environmental tobacco smoke (ETS) at home.Personal NO₂ levels were found to be strongly influenced by indoor NO₂ concentrations. The study supports the use of time–activity patterns along with indoor measurements to predict personal exposure to traffic-related air pollution.     

Residential exposure to traffic noise and risk of incident atrial fibrillation: A cohort study

BackgroundStudies have found long-term exposure to traffic noise to be associated with higher risk for hypertension, ischemic heart disease and stroke. We aimed to investigate the novel hypothesis that traffic noise increases the risk of atrial fibrillation (A-fib).MethodsIn a population-based cohort of 57,053 people aged 50–64 years at enrolment in 1993–1997, we identified 2692 cases of first-ever hospital admission of A-fib from enrolment to end of follow-up in 2011 using a nationwide registry. The mean follow-up time was 14.7 years. Present and historical residential addresses were identified for all cohort members from 1987 to 2011. For all addresses, exposure to road traffic and railway noise was estimated using the Nordic prediction method and exposure to air pollution was estimated using a validated dispersion model. We used Cox proportional hazard model for the analyses with adjustment for lifestyle, socioeconomic position and air pollution.ResultsA 10 dB higher 5-year time-weighted mean exposure to road traffic noise was associated with a 6% higher risk of A-fib (incidence rate ratio (IRR): 1.06; 95% confidence interval (95% CI): 1.00–1.12) in models adjusted for factors related to lifestyle and socioeconomic position. The association followed a monotonic exposure–response relationship. In analyses with adjustment for air pollution, NO_x or NO₂, there were no statistically significant associations between exposure to road traffic noise and risk of A-fib; IRR: 1.04; (95% CI: 0.96–1.11) and IRR: 1.01; (95% CI: 0.94–1.09), respectively. Exposure to railway noise was not associated with A-fib.ConclusionExposure to residential road traffic noise may be associated with higher risk of A-fib, though associations were difficult to separate from exposure to air pollution.     

Indoor air pollution and public policy

In recent years, scientist have come to realize that contaminated air inside buildings is a major route of human exposure to certain air pollutants. While scientific interest in the problem continues to grow, efforts to measure indoor pollution concentrations, define exposure levels, and estimate health risks remain in their infancy. Within this arena, policymakers must deal with the question of how best to protect public health and safety in the face of incomplete and often contradictory information. In the past, official response to environmental pollution has traditionally taken the form of “control by regulation.” However, creation of a regulatory framework for indoor air quality poses special policy issues that suggest the need to explore alternative modes of intervention. Ambient outdoor air is a public good, in the sense that enjoyment by one individual in no way detracts from use or enjoyment by others. Indoor air, on the other hand, is not a public good, especially in private residences. Costs and benefits of maintaining adequate indoor air quality are internalized within households, suggesting the possibility of a private demand for clean indoor air. Promulgation of indoor air quality standards and other regulations must confront the fact that individuals are already making decisions about their own air quality. Regulations might or might not improve these decisions. Development of effective and reasonable policy requires an appreciation of the scope for private action and consideration of the likelihood that public intervention will foster improved private choices. Among the logical and relatively inexpensive modes of intervention are public information programs, development of simple warning devices, and product testing and labeling.     

Recent advances in SO2, NOx, and O3 personal monitoring

Since the air pollution as measured by stationary monitoring stations is a poor indicator of the population exposure, personal monitors are indispensible to health effects studies. This article reviews the current research on the development of personal monitors. Although most of the analytical methods reviewed in this study appear to be sensitive to the levels of the target pollutants NO₂, SO₂, and O₃ generally encountered in indoor and outdoor air, they lack the desired performance characteristics for a personal monitoring device, such as user safety and ease of operation, weight, and maintenance. Electrochemical transducers/sensors, which have not yet been exploited, are attractive candidates for the application to personal monitoring. This technique has an added feature of generating real-time measurements. A few research models and commercially attractive devices that can be used in field studies are included.     

Inequalities in cumulative environmental burdens among three urbanized counties in California

Low-income communities and communities of color often suffer from multiple environmental hazards that pose risks to their health. Here we extended a cumulative environmental hazard inequality index (CEHII) – developed to assess inequalities in air pollution hazards – to compare the inequality among three urban counties in California: Alameda, San Diego, and Los Angeles. We included a metric for heat stress to the analysis because exposure to excessively hot weather is increasingly recognized as a threat to human health and well-being. We determined if inequalities from heat stress differed between the three regions and if this added factor modified the metric for inequality from cumulative exposure to air pollution. This analysis indicated that of the three air pollutants considered, diesel particulate matter had the greatest inequality, followed by nitrogen dioxide (NO₂) and fine particulate matter (PM_2.5). As measured by our index, the inequalities from cumulative exposure to air pollution were greater than those of single pollutants. Inequalities were significantly different among single air pollutant hazards within each region and between regions; however, inequalities from the cumulative burdens did not differ significantly between any two regions. Modeled absolute and relative heat stress inequalities were small except for relative heat stress in San Diego which had the second highest inequality. Our analysis, techniques, and results provide useful insights for policy makers to assess inequalities between regions and address factors that contribute to overall environmental inequality within each region.     

A study of effects of ambient urban air pollution using personal samplers; a preliminary report

Air pollution has been associated with an increased incidence of respiratory disease. However, significant differences may exist between air pollution levels measured at conventional fixed monitoring stations and actual levels inhaled by a subject. Furthermore, studies of effects of air pollution might best be done using asthmatics as study subjects, since they have irritable airways. This is a preliminary report of a study using a control and asthmatic group in which effects of air pollution are assessed by sympton and medication diaries and simple pulmonary function tests. Air pollution exposure is measured using a small portable sampler for particulates, SO₂ and NO₂; these samplers are carried by the subject (“personal”) and are situated inside and outside the home. Levels obtained are compared to data obtained from the same type of sampler located at a fixed monitoring station. Preliminary analysis of the data shows that the levels of pollutants are low and there are significant differences between the four air pollution measurements, with weak correlations among the various measurements. In this preliminary report, change in pulmonary function during the day correlates only with personal NO₂ measurements. This suggests the need for estimating air pollution exposure using “personal” samplers, when investigating health effects.     

The emission inventory of atmospheric industrial pollution sources of the five cities in Zhejiang Province

The amount of several air pollutants emitted in some cities including Hangzhou,Ningbo,Huzhou,Shaoxing and Jiaxing of Zhejiang Province is based on pollution source census data of Zhejiang Province in 2010.This paper focused on the release of air pollutants such as NO_(x2),SO_2,CO,PM2.5,PM10 and VOC,and calculated the total amount of those air pollutants.It analyzed air pollutant emission factors and found that the electricity and heat production industry released the largest amount of pollutants.     

The emission inventory of atmospheric industrial pollution sources of the five cities in Zhejiang Province

The amount of several air pollutants emitted in some cities including Hangzhou, Ningbo, Huzhou, Shaoxing and Jiaxing of Zhejiang Province is based on pollution source census data of Zhejiang Province in 2010. This paper focused on the release of air pollutants such as NO_x, SO₂, CO, PM2.5, PM10 and VOC, and calculated the total amount of those air pollutants. It analyzed air pollutant emission factors and found that the electricity and heat production industry released the largest amount of pollutants.     

技术异质下中国大气污染排放效率的区域差异与影响因素

近年来中国雾霾天气的频繁发生给人们的生产、生活以及身体健康构成巨大威胁。提高大气污染排放效率,深入挖掘大气污染减排潜力是改善中国大气环境质量,减少和消除雾霾天气发生的重要途径。本文根据生态效率理论,充分考虑到不同区域发展的不平衡因素与技术异质性特征,在共同前沿方法框架下科学测算2006—2014年间中国30个省份的大气污染排放效率,在此基础上分析效率的区域差异,利用"技术差距比(TGR)"这一指标衡量东部、中部与西部三大区域之间大气污染排放技术的差距,并从"技术"与"管理"两个维度进一步将各省份大气污染排放无效率分解为"技术差距无效率(TGI)"与"管理无效率(GMI)",以此定位各省份大气污染防治的薄弱环节,进而构建策略矩阵,将全国各省份归入四个不同排放效率特征的方阵,并给出相应的优化路径与措施;深入揭示大气污染排放效率与排放强度之间的内在联系,提出"大气污染排放强度效率"这一全新概念并考察其演化趋势;利用面板Tobit回归模型检验影响我国省际大气污染排放效率与排放技术的外部环境因素。实证结果表明:1中国大气污染排放效率整体水平偏低,年均仅为0.493,污染减排潜力巨大;2中国大气污染排放效率与排放技术的地区差异显著,无论是大气污染排放效率还是排放技术水平,东部地区都是明显高于中部与西部地区;3中国大气污染的实际排放强度明显高于潜在排放强度,这表明大气污染排放强度还存在很大的改进空间;4经济发展、产业结构升级与科技创新对大气污染排放效率与排放技术的提升均有显著促进作用,煤炭消费比重上升与人口密度过大则对其有显著抑制作用;5本文的研究结论支持"波特假说"与"污染避难所"假说。     

Concepts of human exposure to air pollution

In recent years, considerable attention has focused on the concept of “human exposure” to environmental pollutants, but different investigators seem to have developed different definitions of this concept and used different approaches for estimating it. This paper reviews a number of “exposure” studies in a single environmental medium—air pollution—to see how others have defined this concept in the literature. Many previous investigators unfortunately calculate “exposures” by relying on data from fixed air monitoring stations, and they assume that people are located in the same place, usually their residential address, throughout a 24-h period. However, a second body of literature shows that fixed air monitoring stations do not necessarily reflect human exposures, because concentrations observed indoors—in homes, offices, factories, and motor vehicles—differ from those observed at fixed stations, and people usually spend considerable time in these locations. In an effort to standardize the nomenclature dealing with exposures, a definition is proposed in which the pollutant must come into contact with the physical boundary of the person. Then, exposure of person i to pollutant concentration c is viewed as two events occurring jointly: person i is present at a particular location, and concentration c is present at the same location. Mathematical definitions for “integrated exposure,” “average exposure,” and “standardized exposure” with various averaging periods also are introduced. Finally, two different yet compatible research approaches are suggested for determining human exposures to air pollution.     

Short-term effects of air pollution on respiratory morbidity at Rio de Janeiro — PART I: Air Pollution Assessment

Exposure to air pollution has been related with the most varied adverse health outcomes. This study aims to assess the impact of air pollution on the emergency hospitalization for respiratory disease in Rio de Janeiro, Brazil. The study was divided in two parts: Part I specifically addressing the air pollution assessment and Part II addressing the health assessment. Accordingly, this Part I aims to: i) evaluate the concentrations of PM₁₀, SO₂ and CO at two sites in Rio de Janeiro and compare them; ii) analyse the concentrations observed according to the national and international standards; and iii) analyse the air pollutants behaviour, namely, annually, seasonally, daily and considering weekdays/weekends variations. The pollutant concentrations were measured at two different sites in Rio de Janeiro and the analysis was performed for the period between September 2000 and December 2005. Results showed that PM₁₀ concentrations in Rio de Janeiro exceeded the daily and annual standards imposed by the European Union, the Brazilian legislation and WHO guidelines. Regarding SO₂ and CO, concentrations were, generally, below both European and Brazilian standards. Nevertheless, considering WHO guidelines, SO₂ threshold for daily concentrations (20 μg m^− 3) was exceeded around 150 times. Behaviour assessment showed that the influence of traffic is a major factor affecting the air pollution in Rio de Janeiro.Considering the results achieved and the proven health effects of air pollution, strategies should be defined for its reduction, particularly concerning particulate matter, and consequently contribute to the protection of public health.     

Personal monitoring of air pollution exposures

In industrial hygiene and health physics the goal has been to protect the health of the individual. Therefore monitoring the exposure people actually receive has been the principal concern. In regulating public exposures to air pollution, the focus has been much different. Recently, use of personal monitors and alternative means of estimating actual exposures has expanded rapidly. The role of personal monitors in epidemiology, exposure studies, and in supplementing the existing fixed station monitoring network for establishing trends and for regulatory purposes is discussed. The implications for air quality standards in recent findings of personal and indoor exposures is considered. New developments that are needed, and those that are not needed, are outlined.