A method to derive the relationship between the annual and short-term air quality limits--analysis using the WHO Air Quality Guidelines for health protection.

The World Health Organization (WHO) Air Quality Guidelines (AQG) were launched in 2006, but gaps remain in evidence on health impacts and relationships between short-term and annual AQG needed for health protection. We tested whether relationships between WHO short-term and annual AQG for particulates (PM10 and PM2.5) and nitrogen dioxide (NO2) are concordant worldwide and derived the annual limits for sulfur dioxide (SO2) and ozone (O3) based on the short-term AQG. We obtained air pollutant data over seven years (2004-2010) in seven cities from Asia-Pacific, North America and Europe. Based on probability distribution concept using maximum as the short-term limit and arithmetic mean as the annual limit, we developed a new method to derive limit value one from another in each paired limits for each pollutant with capability to account for allowable exceedances. We averaged the limit derived each year for each city, then used meta-analysis to pool the limit values in all cities. Pooled mean short-term limit for NO2 (140.5µg/m(3) [130.6-150.4]) was significantly lower than the WHO AQG of 200µg/m(3) while for PM10 (46.4µg/m(3) [95CI:42.1-50.7]) and PM2.5 (28.6µg/m(3) [24.5-32.6]) were not significantly different from the WHO AQG of 50 and 25µg/m(3) respectively. Pooled mean annual limits for SO2 and O3 were 4.6µg/m(3) [3.7-5.5] and 27.0µg/m(3) [21.7-32.2] respectively. Results were robust in various sensitivity analyses. The distribution relationships between the current WHO short-term and annual AQG are supported by empirical data from seven cities for PM10 and PM2.5, but not for NO2. The short-term AQG for NO2 should be lowered for concordance with the selected annual AQG for health protection.

Communicating air pollution-related health risks to the public: an application of the Air Quality Health Index in Shanghai, China.

The Air Quality Health Index (AQHI) was originally developed in Canada. However, little is known about its validity in communicating morbidity risks. We aimed to establish the AQHI in Shanghai, China, and to compare the associations of AQHI and existing Air Pollution Index (API) with daily mortality and morbidity. We constructed the AQHI as the sum of excess total mortality associated with individual air pollutants, and then adjusted it to an arbitrary scale (0-10), according to a time-series analysis of air pollution and mortality in Shanghai from 2001 to 2008. We examined the associations of AQHI with daily mortality and morbidity, and compared these associations with API from 2005 to 2008. The coefficients of short-term associations of total mortality with particulate matter with an aerodynamic diameter less than 10 µm (PM(10)), PM(2.5) and nitrogen dioxide (NO(2)) were used in the establishment of AQHI. During 2005-2008, the AQHI showed linear non-threshold positive associations with daily mortality and morbidity. A unit increase of the PM(10)-AQHI was associated with a 0.90% [95% (confidence interval, CI), 0.43 to 1.37], 1.04% (95%CI, 0.04 to 2.04), 1.62% (95%CI, 0.39 to 2.85) and 0.51% (95%CI, 0.09 to 0.93) increase of current-day total mortality, hospital admissions, outpatient visits and emergency room visits, respectively. The PM(2.5)-AQHI showed quite similar effect estimates with the PM(10)-AQHI. In contrast, the associations for API were much weaker and generally statistically insignificant. The AQHI, compared with the existing API, provided a more effective tool to communicate the air pollution-related health risks to the public.

Influence of a portable air treatment unit on health-related quality indicators of indoor air in a classroom.

During periods of two weeks in February and June 2010 the performance of portable air treatment units (PATUs) was evaluated in a primary school classroom using indicators of indoor air quality. Air samples were collected in an undisturbed setting on weekend days and in an occupied setting during teaching hours. In the first week PATUs were turned off and in the second week they were turned on. On weekend days PATUs reduced indoor levels of PM-10 by 87% in February and by 70% in June compared to weekend days when PATUs were turned off. On schooldays, indoor PM-10 was increased by 6% in February and reduced by 42% in June. For PM-2.5 reductions on weekend days were 89% in February and 80% in June. On school days PM-2.5 was increased by 15% in February and reduced by 83% in June. Turning on the PATUs reduced total VOC by 80% on weekend days and by 57% on school days (but not in June). No influence on formaldehyde, NO(2), O(3) and molds was observed. PATUs appeared to be less effective in removal of air pollutants when used in an occupied classroom compared to an unoccupied setting. Our study suggests that such devices should be tested in real-life settings to evaluate their influence on indoor air quality.

Application of nonparametric regression methods to study the relationship between NO2 concentrations and local wind direction and speed at background sites.

Background concentrations of nitrogen dioxide (NO(2)) are not constant but vary temporally and spatially. The current paper presents a powerful tool for the quantification of the effects of wind direction and wind speed on background NO(2) concentrations, particularly in cases where monitoring data are limited. In contrast to previous studies which applied similar methods to sites directly affected by local pollution sources, the current study focuses on background sites with the aim of improving methods for predicting background concentrations adopted in air quality modelling studies. The relationship between measured NO(2) concentration in air at three such sites in Ireland and locally measured wind direction has been quantified using nonparametric regression methods. The major aim was to analyse a method for quantifying the effects of local wind direction on background levels of NO(2) in Ireland. The method was expanded to include wind speed as an added predictor variable. A Gaussian kernel function is used in the analysis and circular statistics employed for the wind direction variable. Wind direction and wind speed were both found to have a statistically significant effect on background levels of NO(2) at all three sites. Frequently environmental impact assessments are based on short term baseline monitoring producing a limited dataset. The presented non-parametric regression methods, in contrast to the frequently used methods such as binning of the data, allow concentrations for missing data pairs to be estimated and distinction between spurious and true peaks in concentrations to be made. The methods were found to provide a realistic estimation of long term concentration variation with wind direction and speed, even for cases where the data set is limited. Accurate identification of the actual variation at each location and causative factors could be made, thus supporting the improved definition of background concentrations for use in air quality modelling studies.

Study of the uncertainty in NO2 chemiluminescence measurements due to the NO-O3 reaction in sampling lines.

INTRODUCTION: The change in light intensity that takes place when an ambient air sample is drawn into the detection chamber of a chemiluminescence monitor generates changes in the concentrations of several species, such as NO(2), NO and O(3). Although this phenomenon has been known for several decades, there is still no commonly accepted approach on when or how to correct for it in NO(2) and O(3) readings. DISCUSSION: In this work, we have assessed the expanded uncertainty of two chemiluminescence NO( x ) analysers commercially available according to EN 14211:2005, with the aim of establishing the maximum allowable standard uncertainty due to the reaction between NO and O(3) in the sampling system. CONCLUSION: Although this maximum allowable uncertainty cannot be a universal value-as it will depend on the performance of each analyser-our results have led us to propose the conservative value of 2%. We have also proposed a methodology for improving data quality which could be easily implemented by those responsible for air quality data validation.

Air pollution forecasting in Ankara, Turkey using air pollution index and its relation to assimilative capacity of the atmosphere.

Spatial and temporal variations in concentrations of CO, NO, NO(2), SO(2), and PM(10), measured between 1999 and 2000, at traffic-impacted and residential stations in Ankara were investigated. Air quality in residential areas was found to be influenced by traffic activities in the city. Pollutant ratios were proven to be reliable tracers to differentiate between different sources. Air pollution index (API) of the whole city was calculated to evaluate the level of air quality in Ankara. Multiple linear regression model was developed for forecasting API in Ankara. The correlation coefficients were found to be 0.79 and 0.63 for different time periods. The assimilative capacity of Ankara atmosphere was calculated in terms of ventilation coefficient (VC). The relation between API and VC was investigated and found that the air quality in Ankara was determined by meteorology rather than emissions.

U.S.-Canada cooperation: the U.S.-Canada air quality agreement.

The impetus for the Canada-U.S. Air Quality Agreement was transboundary acid rain in eastern North America. This problem drove the parties to develop a bilateral agreement that not only addressed this issue, but also set up a broad and flexible framework to address other air quality problems. In 2000, the Ozone Annex to reduce smog and its precursor pollutants was negotiated. A transboundary particulate matter (PM) science assessment in 2004 led to the commencement of negotiation of a PM annex in late 2007. Over the course of 15 yr, Canada and the United States also developed innovative cooperative arrangements. Two transboundary airshed dialogues became important sources of practical on-the-ground cooperation in the Georgia Basin-Puget Sound and the Great Lakes Basin. In addition to providing the basis for ongoing international dialogue, these transboundary airshed projects resulted in changes to administrative practices as the parties exchange information and learn from each other in ways that benefit the airshed community. The nature of the Air Quality Agreement also enabled both Canada and the United States to address concerns each has had about specific pollutant sources and to address them in ways that avoided confrontation and resulted in air quality improvements for people living in the airsheds. Case studies of three of the "informal consultations" that have occurred under the agreement are described: where discussions occurred around a power plant in Michigan, a power plant in Saskatchewan, and a steel mill in Ontario. More than an agreement, this relationship has built a capacity to deal with common problems. Fostering such a relationship with its implicit transfer of knowledge and experience has opened doors for discussions on a new Clean Air framework in Canada and joint analyses of cross-border sulfur dioxide (SO2) and nitrogen oxides (NOx) emissions caps and trading. U.S. experience with cap and trading is highlighted for background and context. The flexibility inherent in the agreement provides a platform for future air quality issues and continued communication without borders.

Challenges to managing air pollution.

There is never enough money, time, or resources to do all the things that need to be done--a statement that is true both for governments and individuals. For governments, this fact implies that (1) priorities need to be established; (2) goals are essential to be set to address these priorities, partly with an eye toward maximizing the net benefits to society; and (3) policies need to be implemented to reach those goals efficiently and effectively. In this article, major challenges of managing air pollution in each of these areas are examined.

WHO Air Quality Guidelines for Europe.

This article describes the WHO Air Quality Guidelines and highlights two projects that were initiated to update the risk assessment of the main air pollutants: "Systematic Review of Health Aspects of Air Quality in Europe" and the "Global Update of WHO Air Quality Guidelines." The report of the Systematic Review emphasizes that the accumulated evidence is sufficient to require actions reducing the health impacts of air pollution in Europe. The global update of the air quality guidelines focuses on particulate matter (PM), ozone, NO2, and SO2 and addresses issues associated with the practical feasibility of attaining the guidelines in developing countries. The article illustrates WHO's activities toward gathering the best available international scientific evidence to support air quality policy development in all regions of the world.

Air quality management in Mexico.

Several significant program and policy measures have been implemented in Mexico over the past 15 yr to improve air quality. This article provides an overview of air quality management strategies in Mexico, including (1) policy initiatives such as vehicle use restrictions, air quality standards, vehicle emissions, and fuel quality standards, and (2) supporting programs including establishment of a national emission inventory, an air pollution episodes program, and the implementation of exposure and health effects studies. Trends in air pollution episodes and ambient air pollutant concentrations are described.

Development of an aggregate Air Quality Index for an urban Mediterranean agglomeration: relation to potential health effects.

It is very useful for the authorities and the people to have daily easy understandable information about the levels of air pollution and the proper measures to be taken for the protection of human health. In this paper we develop an aggregate Air Quality Index (AQI) based on the combined effects of five criteria pollutants (CO, SO2, NO2, O3 and PM10) taking into account the European standards. We evaluate it for each monitoring station and for the whole area of Athens, Greece, an area with serious air pollution problems. A comparison was made with a modified version of Environmental Protection Agency/USA (USEPA) maximum value AQI model adjusted for European conditions. Hourly data of air pollutants from 4 monitoring stations, available during 1983-1999, were analysed for the development of the proposed index. The analysis reveals the Athenian population exposure reaches high levels and during last years a gradual increase of days with unhealthy conditions was detected. The proposed aggregate model estimates more effectively the exposure of citizens comparing with the modified USEPA maximum value model, because counts the impact of all the pollutants measured. Towards the informing and protection of the citizens in an urban agglomeration this model advantages as a political and administrative tool for the design of abatement strategies and effective measures of intervention.

An analysis of effects of San Diego wildfire on ambient air quality.

The impact of major gaseous and particulate pollutants emitted by the wildfire of October 2003 on ambient air quality and health of San Diego residents before, during, and after the fire are analyzed using data available from the San Diego County Air Pollution Control District and California Air Resources Board. It was found that fine particulate matter (PM) levels exceeded the federal daily 24-hr average standard during the fire. There was a slight increase in some of the gaseous pollutants, such as carbon monoxide, which exceeded federal standards. Ozone (O3) precursors, such as total hydrocarbons and methane gases, experienced elevated concentration during the fire. Fortunately, the absence of sunlight because of the cloud of thick smoke that covered most of the county during the fire appears to have prevented the photochemical conversion of the precursor gases to harmful concentrations of O3. Statistical analysis of the compiled medical surveillance data has been used to establish correlations between pollutant levels in the region and the resultant health problems experienced by the county citizens. The study shows that the increased PM concentration above the federal standard resulted in a significant increase in hospital emergency room visits for asthma, respiratory problems, eye irritation, and smoke inhalation. On the basis of the findings, it is recommended that hospitals and emergency medical facilities engage in pre-event planning that would ensure a rapid response to an impact on the healthcare system as a result of a large wildfire and appropriate agencies engage in the use of all available meteorological forecasting resources, including real-time satellite imaging assets, to accurately forecast air quality and assist firefighting efforts.

The German view: effects of nitrogen dioxide on human health--derivation of health-related short-term and long-term values.

The presented overview concerning health relevant effects caused by nitrogen dioxide (NO2) resumes the current state of results from animal experiments and human studies (epidemiology and short-term chambers studies). NO2 concentrations applied in animal experiments were mostly considerably higher than in ambient air. Therefore, short- and long-term limit values were derived from human data. Experimental studies conducted with humans demonstrate effects after short-term exposure to concentrations at or above 400 microg NO2/m3. Effects on patients with light asthma could not be observed after short-term exposure to concentrations below 200 microg/m3. On basis of epidemiological long-term studies a threshold below which no effect on human health is expected could not be specified. Two short-term limit values have been proposed to protect public health: a 1-h value of 100 microg/m3 and a 24-h mean value of 50 microg/m3. Due to the limitations of epidemiological studies to disentangle effects of single pollutants, a long-term limit value cannot be easily derived. However, applying the precautionary principle, it is desirable to adopt an annual mean of 20 microg NO2/m3 as a long-term mean standard to protect public health.

[Qualitative and quantitative characteristics of atmospheric air pollution in an industrial city]. / Kachestvennaia i kolichestvennaia kharakteristika zagriazneniia atmosfernogo vozdukha promyshlennogo goroda.

The data obtained as result of studies of qualitative and quantitative characteristics of urban ambient air give the ground to make a conclusion that air pollution in the areas of industrial enterprises is of a local character. A great part of urban territory is polluted with the major harmful impurities (carbon oxide, nitrogen dioxide, sulfur dioxide, dust). The studies carried out open up perspective to investigate the influence of harmful impurities on the population health and to develop activities aimed at the reduction of the level of chemicals' concentration in the air.