The impact of urban spatial structure on air pollution: empirical evidence from China

Environment, Development and Sustainability - For a long time, air pollution caused by unreasonable urban spatial structure and excessive urban sprawl has been a prominent environmental problem in...     

Indoor air pollution

As national trends accelerate towards the reduction of ventilation and infiltration rates in buildings, coupled with an increased use of synthetic chemicals in the indoor environment, a new phenomenon has arisen: the “sick building” syndrome. Traditional approaches to environmental health developed for the outdoor air, or for the industrial occupational setting, are inadequate to deal with this problem. It is argued that a comprehensive approach to the problem of indoor air pollution is necessary to protect public health.     

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.     

Using air pollution based community clusters to explore air pollution health effects in children

To study respiratory health effects of long-term exposure to ambient air pollutant mixture, we observed 7058 school children 5-16 years of age living in the four Chinese cities of Lanzhou, Chongqing, Wuhan, and Guangzhou. These children were enrolled from elementary schools located in eight districts, one urban district and one suburban district in each of the above cities. Ambient levels of PM(2.5), PM(10-2.5), total suspended particles (TSP), SO(2), and NO(x) were measured in these districts from 1993 to 1996. Based on a cluster analysis of arithmetic mean concentrations of PM(2.5), PM(10-2.5), (TSP-PM(10)), SO(2), and NO(x), we classified these children into four ordinal categories of exposure to ambient air pollutant mixtures. We tested for exposure-response relationships using logistic regression models, controlling for relevant covariates. We observed monotonic, positive relationships of exposure to the pollutant mixture with prevalence rates of cough with phlegm and wheeze. Other outcomes were not associated with the exposure in a monotonic exposure-response pattern. Even so, odds ratios for cough, phlegm, bronchitis, and asthma in the higher exposure district clusters were all higher than in the lowest exposure district cluster. We found evidence that exposure to the pollutant mixtures had adverse effects on children living in the four Chinese cities.     

Particulate air pollution in Lanzhou China

Concentrations of total suspended particles (TSP) and PM(10) in Lanzhou China have been kept high for the past two decades. Data collected during the intensive observational period from October 1999 to April 2001 show high TSP and PM(10) concentrations. Starting from November, the PM(10) pollution intensifies, and reaches mid to high alert level of air pollution, continues until April next year, and is at low alert level in the summer. In the winter and spring, the TSP concentration is 2-10 times higher than the third-level criterion of air quality (severe pollution). Effects of intrinsic factors (sources of pollution) and remote preconditions (propagation of dust storms) for severe PM(10) and TSP pollution in Lanzhou are analyzed.     

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.     

基于理性预期理论的大气污染经济成本评估

我国大气污染形势严峻,科学合理地评估大气污染的经济损失不仅有益于政策效益分析,同时是“绿色国民经济”核算的一项基础性工作。基于我国2013年2月到2018年7月的区县月度房屋交易数据和7种大气污染指标(AQI、SO₂、NO₂、CO、O₃、PM₁₀、PM_2.5)的浓度数据,运用特征价格模型实证量化大气污染物减少的边际支付意愿(MWTP)和总经济损失。首先通过改变理性预期的时间段验证理性预期假设的成立,在此基础上采用理性预期方法解决遗漏变量所导致的内生性问题。研究结果显示:①NO₂、CO、PM_2.5和PM₁₀每上升1μg/m³,房价分别降低约2.04%、0.028%、0.34%和0.39%;而SO₂与O₃对房价的影响并不显著。②近年来大气污染的经济损失有所降低,政府的治理效果显著,但仍不容小觑。2013年AQI、PM₁₀和PM_2.5未达标导致的经济损失分别约为35600亿元、19300亿元和24100亿元,约占当年GDP的6.06%、3.29%和4.11%;2018年分别降低至19200亿元、5300亿元和6700亿元,占当年GDP的2.14%、0.60%和0.74%。尽管PM₁₀和PM_2.5浓度也在逐年下降,但仍未达到《环境空气质量标准》所要求的二级限值。最终评估结果显示,PM₁₀和PM_2.5二者导致的经济损失的加总数值,与AQI得到的数值相差无异。进一步证实了我国当前大气污染导致的社会经济福利损失主要是来自PM₁₀和PM_2.5的超标,因此治理“雾霾”是改善当前空气质量的关键。     

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.     

Models for human exposure to air pollution

Four models for human exposure to air pollution are discussed and compared. The simple microenvironment monitoring model measures pollutant concentrations at fixed locations, regarded as proxies for similar locations or microenvironments. Since this model does not require pollutant measurements on the individual level, it is easy to implement. However, the model can only be used to estimate the average exposure in a population, and it does not provide any estimate of the variability and distribution of individual exposures. The replicated microenvironment monitoring model provides some estimates of the variability and distribution. However, because of the possible discrepancy between the microenvironment concentration distribution and the individual concentration distribution, some adjustment might be necessary. Integrated personal monitoring allows direct estimation of the average exposure as well as the variability and distribution of individual exposures. Coupled with the appropriate time budget data, a regression analysis can be applied to estimate the contribution from each microenvironment type. However, possible collinearity problems might result in low precision in those estimates. Moreover, it might be difficult to adjust for a possible Hawthorne effect. Continuous personal monitoring has the advantage of recording exposure in each microenvironment type separately, allowing direct estimation of the average exposure as well as the variability and distribution of exposures in each microenvironment type. Moreover, it can also be conducted in conjunction with a two-stage sampling scheme, using information from a large data base on activity patterns, thereby making more efficient use of the monitoring data. It is also easier to adjust for a possible Hawthorne effect in this design.     

Ambient air pollution and children's lung function in China

ObjectiveTo describe the correlations between ambient air pollutants (TSP, SO₂, NO_x) and the level of children's lung function (FVC, FEV₁, MMEF) in China.MethodsWe collected the research articles on ambient air pollution and children's lung function published from 1985 to 2006 and selected 11 articles finally according to the following criteria: (1) Children between the age of 7 and 15 as objects; (2) Local air quality monitoring results were reported; (3) Strict quality control was taken when testing children's lung function; (4) The results were expressed by the average of measured value. Then we analyzed the correlation relationship between the level of ambient air pollutants and children's lung function and compared the effects of ambient air pollutants on children's lung function of boy and girl.ResultsThe selected articles included the results of 7 cities in China. Among them, the results of 6 cities' studies revealed that the levels of children's lung function were significantly lower in the areas with heavy ambient air pollution than those in the areas with light ambient air pollution. According to the articles, the average levels of TSP were at the range of 0.084 mg/m³–0.835 mg/m³, SO₂ were 0.013 mg/m³–0.929 mg/m³, NO_x were 0.044 mg/m³–0.229 mg/m³. Correlation analysis showed significant negative correlation between the levels of TSP and SO₂ and children's FVC and FEV₁, as well as the levels of NO_x and children's MMEF. The correlation coefficient was ? 0.797 (t = ? 4.384, P = 0.001) between TSP and FVC, ? 0.693 (t = ? 4.190, P < 0.001) between Ln (SO₂) and FVC, ? 0.886 (t = ? 5.392, P = 0.001) and ? 0.685 (t = ? 4.101, P = 0.001) between FEV₁ and TSP and Ln (SO₂), and ? 0.973 (t = ? 5.993, P = 0.027) between NO_xNO_x and MMEF, respectively. The results also suggested that the decreases of lung function for girl with the increasing of ambient air pollution were significantly greater for boy.ConclusionThe levels of ambient air TSP and SO₂ correlated with the damage of the big airway function of children, while NO_xNO_x affected the small airway function chiefly. Furthermore, lung function of girl was more susceptible to ambient air pollutants than boy.     

Human mortality in Cyprus: the role of temperature and particulate air pollution

Climatic change results in increased occurrence of heat waves, and the thermal stress caused by such phenomena is leading to higher levels of heat-related mortality worldwide. This study is the first to examine the effect of extreme weather on mortality in Cyprus. It investigates the individual effect of meteorological indicators on mortality, as well as the role of particulate air pollution (PM₁₀). A generalized linear model (GLM) with quasi-Poisson regression was implemented. GLM included a temperature function and was adjusted for relative humidity and seasonality. The temperature function was developed under a newly developed framework of distributed lag nonlinear models, which capture nonlinearities and delayed effects of heat simultaneously. GLM was extended to examine the confounding effect of air pollution. All the results on heat effects are presented. High temperatures had a significant effect on mortality with increased mortality rates, independent of humidity and seasonality. Mortality risk increased steeply above a temperature threshold. A direct heat effect was shown, with higher risk on the current and next day of a severe heat event. PM₁₀ was not found to have a confounding effect on the temperature–mortality relationship, since the strength of this relationship remained after the inclusion of PM₁₀ in the model. Differences existed between urban and coastal areas.     

Evaluation of some air pollution indicators in Turkey

This article intends to shed a light on air quality in Turkey and compare air pollutant emissions on a national scale with that of the European countries. In order to estimate the quantities of Turkish emissions in the past and their future predictions, a national emission inventory was prepared with respect to five major pollutants consisting of particulate matter(PM), SOx, NOx, non-methane volatile organic compounds, and CO with 5-year intervals between 1985 and 2005. The results suggest that Turkey is a rather large emission source at the European scale, although emission indicators on unit area and per capita were shown to be somewhat smaller in magnitude. Levels of air pollution in some of the big cities in Turkey were also evaluated from available national monitoring data. These evaluations for the urban air qualities covered SO2 and PM parameters between 1986 and 1996, and results were compared with the present Turkish air quality limits, their probable revisions, WHO (Europe) guidelines and related EC directives. Results showed that the air quality limits were not met, especially during the winter periods in Turkish cities. Urban air pollutants characterizing the air in Turkish cities other than SO2 and PM, however, could not have been evaluated as these pollutants were not systematically monitored in these cities.     

Control of industrial air pollution through sustainable development

The environmental issue has become a major subject in the last few decades affecting science and technology throughout the world due to the serious environmental impacts caused by industrial air pollution. Consequently, pulse jet filtration has become the preferred choice all around the world. Researchers are continuously striving for new concepts of more energy-efficient and compact particulate collector which can meet future emission limits and operating requirements. The system can also satisfy stringent emission norms and if required, it can be embedded with new technique for simultaneous control of particulate and gaseous pollutants. In the recent past, stress is also being given to having control over the source to reduce or eliminate waste, and finally, on waste management. Prevention is frequently more cost-effective than control. The paper discusses all these methodology toward sustainability in the perspective of effective control of industrial air pollution.     

Carbon-14, tree rings,and urban air pollution

Differences in natural ¹⁴C content of rings from trees from urban and rural locations have been compared on a year by year basis. The differences as a fraction of the urban tree's radioactivity reflect the local excess ¹⁴C-free carbon dioxide from fossil fuel combustion in the urban environment. New York City, Boston, and Washington, D.C., show different degrees of excess carbon dioxide. New York City averages about 6% excess carbon dioxide between 1950 and 1970. From this is infered an average carbon monoxide concentration during this period of 5 ppm.     

跨界大气污染治理体系和政策措施——欧洲经验及对中国的启示

大气污染具有明显的跨界特性,跨区域联防联治机制是大气污染治理的重要手段。欧洲跨界大气污染治理具有完整的治理体系和丰富的实践经验,取得了显著成就,充分借鉴和吸收欧洲跨界大气污染治理的经验,对提高中国大气污染治理的科学性和有效性、推动解决大气污染治理难题具有重要意义。本文深入分析了欧洲跨界大气污染治理的背景、制度演化、治理体系和政策措施,结果发现,欧洲跨界大气污染治理机制是以EMEP为基础、以CLRTAP为核心、八项议定书为补充的不断扩展治理领域和政策边界的动态过程,其治理政策的制定表现出明显的阶段性特征。从科学化定量体系和制度化保障体系两个维度总结了欧洲跨界大气污染治理的主要措施,结合中国实际,对中国跨界大气污染治理提出了政策建议:(1)建立健全大气治理立法及配套执行体系,并严格落实问责;(2)尽快建立和完善跨界大气污染监测评估系统;(3)科学划分大气污染治理区域,成立跨区域组织领导机构;(4)加快研究制定符合国情的跨区域生态补偿机制。     

Risk perception research: socio-cultural perspectives on the public experience of air pollution

This paper reviews recent work in the field of risk perception research, taking its examples primarily from work relating to air pollution issues. The paper opens with a brief discussion of the psychological literature on risk perception, in order to set out the key insights, criticisms and more recent developments associated with such approaches, before turning to the findings of recent socio-cultural analyses of perceptions of air pollution. This account, which considers how social and cultural factors influence the way in which people interpret and make sense of risk, draws linkages with psychological risk perception research, revealing that over the last decade there has been a pronounced degree of convergence between the conclusions being reached across these two (historically disparate) fields of research. The paper concludes by evaluating the relevance of risk perception research for the science and policy of risk assessment and management.     

An online air pollution forecasting system using neural networks

In this work, an online air pollution forecasting system for Greater Istanbul Area is developed. The system predicts three air pollution indicator (SO(2), PM(10) and CO) levels for the next three days (+1, +2, and +3 days) using neural networks. AirPolTool, a user-friendly website (http://airpol.fatih.edu.tr), publishes +1, +2, and +3 days predictions of air pollutants updated twice a day. Experiments presented in this paper show that quite accurate predictions of air pollutant indicator levels are possible with a simple neural network. It is shown that further optimizations of the model can be achieved using different input parameters and different experimental setups. Firstly, +1, +2, and +3 days' pollution levels are predicted independently using same training data, then +2 and +3 days are predicted cumulatively using previously days predicted values. Better prediction results are obtained in the cumulative method. Secondly, the size of training data base used in the model is optimized. The best modeling performance with minimum error rate is achieved using 3-15 past days in the training data set. Finally, the effect of the day of week as an input parameter is investigated. Better forecasts with higher accuracy are observed using the day of week as an input parameter.     

Long-term air pollution exposure and diabetes in a population-based Swiss cohort

Air pollution is an important risk factor for global burden of disease. There has been recent interest in its possible role in the etiology of diabetes mellitus. Experimental evidence is suggestive, but epidemiological evidence is limited and mixed. We therefore explored the association between air pollution and prevalent diabetes, in a population-based Swiss cohort.We did cross-sectional analyses of 6392 participants of the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults [SAPALDIA], aged between 29 and 73 years. We used estimates of average individual home outdoor PM₁₀ [particulate matter <10 μm in diameter] and NO₂ [nitrogen dioxide] exposure over the 10 years preceding the survey. Their association with diabetes was modeled using mixed logistic regression models, including participants' study area as random effect, with incremental adjustment for confounders.There were 315 cases of diabetes (prevalence: 5.5% [95% confidence interval (CI): 2.8, 7.2%]). Both PM₁₀ and NO₂ were associated with prevalent diabetes with respective odds ratios of 1.40 [95% CI: 1.17, 1.67] and 1.19 [95% CI: 1.03, 1.38] per 10 μg/m³ increase in the average home outdoor level. Associations with PM₁₀ were generally stronger than with NO₂, even in the two-pollutant model. There was some indication that beta blockers mitigated the effect of PM₁₀. The associations remained stable across different sensitivity analyses.Our study adds to the evidence that long term air pollution exposure is associated with diabetes mellitus. PM₁₀ appears to be a useful marker of aspects of air pollution relevant for diabetes. This association can be observed at concentrations below air quality guidelines.     

Relationship between air pollution and daily mortality in a subtropical city: Taipei, Taiwan

Air pollution has been associated with daily mortality in numerous studies over the past decade. However most of these studies were conducted in the United States and Europe with relatively few done in Asia. In the current study, the association between ambient air pollution and daily mortality in Taipei, Taiwan's largest city which has a subtropical climate was undertaken, for the period 1994-1998 using a case-crossover analysis. This design is an alternative to Poisson time series regression for studying the short-term adverse health effects of air pollution. The air pollutants examined included particulate matter (PM(10)), sulfur dioxide (SO(2)), ozone (O(3)), nitrogen dioxide (NO(2)), and carbon monoxide (CO). The largest observed effect, which was without statistical significance, was seen for NO(2) and CO levels on deaths due to respiratory diseases (ORs=1.013 and 1.014, respectively). The well established link between air pollution levels and daily mortality may not be as strong in cities in subtropical areas, although other factors such as differences in pollutant mix or the underlying health of the population may explain the lack of a strong association in this study. Further studies of this type in cities with varying climates and cultures are needed.