Evaluation of a year-long dispersion modelling of PM10 using the mesoscale model TAPM for Christchurch, New Zealand

This paper examines the utility of The Air Pollution Model (TAPM; version 2) in simulating meteorology and dispersion of PM(10) for 1999 over the coastal city of Christchurch, New Zealand. Christchurch usually experiences severe degradation in air quality during austral winter. The formation of a nocturnal inversion layer and the emissions of particulate matter (PM(10)) mainly from solid fuel home heating appliances lead to severe smog episodes on an average of 30 nights during winter. The complex local topography surrounding the city in combination with influences from the urban areas can produce complicated boundary layer winds during quiescent weather. Simulated PM(10) data are used for construction of annual exposure maps for the urban areas in order to assess the health impact of air pollutants due to chronic exposure (presented in an accompanying paper). Meteorology and PM(10) dispersion results are statistically compared with the only permanent air pollution monitoring station available in order to evaluate the model's performance. Statistical measures such as the Index of Agreement (IOA) between modelled and measured data indicate that the model performs well. IOA is greater than 0.6 for meteorological variables, and various calculated skill scores place confidence in the model's performance. However, TAPM has a tendency to overestimate surface wind speed over urban areas during stagnant nocturnal conditions, resulting in quick flushing of pollutants.     

Geothermal ground gas emissions and indoor air pollution in Rotorua, New Zealand

The emission of toxic gases from the soil is a hazard in geothermal regions that are also urbanized because buildings constructed on geothermal ground may be subject to the ingress of gases from the soil directly into the structure. The Rotorua geothermal field, New Zealand, is extensively urbanized but to date no studies have evaluated the extent of the ground gas hazard. The main gases emitted are hydrogen sulphide (H2S) and carbon dioxide (CO2), both of which are highly toxic and denser than air. This paper reports preliminary findings from a study of selected buildings constructed in the gas anomaly area. Properties were investigated for evidence of ingress by H2S, CO2, and 222Rn, with a view to determine the means and rates of gas entry and the nature of any consequent hazard. H2S and CO2 were investigated using infrared active gas analysers and passive detector tubes left in place for 10-48 h. 222Rn was measured over a period of 3 months by poly-allyl diglycol carbonate sensors. Eight of the nine buildings studied were found to suffer problems with soil gases entering the indoor air through the structure. The primary means of gas entry was directly from the ground through the floors, walls, and subsurface pipes. Indoor vents were located and found emitting up to approximately 200 ppm H2S and approximately 15% CO2, concentrations high enough to present an acute respiratory hazard to persons close to the vent (e.g., children playing at floor level). In some properties, gas problems occurred despite preventative measures having been made during construction or during later renovations. Typically, these measures include the under-laying of concrete floors with a gas-proof butanol seal, under-floor ventilation systems or the installation of positive-pressure air conditioning. Recently constructed buildings (<10 years) with butanol seals were nevertheless affected by ground gas emissions, and we conclude that such measures are not always effective in the long term.     

Elevated concentrations of 1-hydroxypyrene in schoolchildren during winter in Christchurch, New Zealand

Particulate air pollution is significantly elevated during the winter in Christchurch, New Zealand, largely attributable to use of wood burners for domestic home heating, topography, and meteorological conditions. Polycyclic aromatic hydrocarbons (PAHs) are a key component of airborne particulate matter (PM) and urinary 1-hydroxypyrene (1-OHP) has previously been used to assess exposure of people to PAHs. We examined urinary 1-OHP in Christchurch male non-smoking schoolchildren (12-18 yr) on two occasions after high pollution events (48 and 72 microg PM(10)/m(3) 24-h average) and two occasions during periods of low pollution (19 and 12 microg PM(10)/m(3)). Concentrations of urinary 1-OHP were significantly elevated in the students during high pollution events (median (mean+/-SD) 0.043 (0.051+/-0.032) and 0.042 (0.060+/-0.092) micromol OHP/mol creatinine respectively) compared with low pollution periods (median (mean+/-SD) 0.019 (0.026+/-0.032) and 0.025 (0.028+/-0.018) micromol/mol creatinine respectively). The observed 1-OHP concentrations are at the lower end of those determined in children and non-occupationally exposed adults in international studies and suggest a generally low exposure to PAHs. The increased urinary 1-OHP concentrations following nights of elevated particulate concentrations in ambient air suggest increased exposure to ambient air pollution during winter time, and could potentially be used as a biomarker of exposure in this population.     

Characterisation and quantification of the sources of PM10 during air pollution episodes in the UK

Data for concentrations of PM(10) and gaseous pollutants from sites in the UK Automatic Urban and Rural Network have been examined during periods of elevated concentrations of PM(10). The ratios of concentrations of PM(10) to those of the other pollutants were used to determine the most probable source of the additional particles. The hypothesis is that because the concentrations of PM(10) were divided by those of the other pollutants, the ratio should decrease when PM(10) and the other pollutants have a common source. Conversely, the ratio should increase when the sources are different. During episodes where road traffic was the most probable source of the additional particles, the ratios of concentrations of PM(10) to carbon monoxide and oxides of nitrogen did decrease, but the comparable ratios for sulphur dioxide and ozone increased. In contrast, during episodes known to have been caused by construction activity, all these ratios increased. This is taken to show that the basic hypothesis is valid. For prolonged episodes, it was possible to use data averaged over the total duration of the episode for the purposes of source identification. For sporadic construction, or other short-duration episodes, it was necessary to use time series data. The data have also been used to calculate the differences between hourly average concentrations of pollutants measured during episodes and long-term hourly average concentrations. These have been used to model the additional PM(10) during air pollution episodes associated with construction activities and road traffic emissions. This confirms the lack of relationship between PM(10) and other pollutants during construction works. During episodes arising from road traffic emissions, there was good agreement between measured and modelled additional concentrations of PM(10) when an appropriate factor, F, related to the contribution of road traffic emissions to PM(10) at different site types was applied. The values used were 0.2 (Suburban), 0.3 (Urban Background/Urban Centre), and 0.5 (Roadside), representing 20%, 30%, and 50% contributions from road traffic, respectively.     

Spatial variations in awareness of air pollution distributions

The accuracy of people's information concerning the spatial extent of air pollution in Christchurch is tested. Overall, the information was generally accurate, though people were more aware of the smoke pollution in the inner city area than of the sulphonation in an outer suburb. Of groups living in different parts of the city, residents of the more polluted areas are more aware of the local problems than are the population as a whole, whereas residents of the “cleaner” suburbs tend to over‐stress this characteristic.     

The Spatial Patterning of Alcohol Outlets in Post-Disaster Christchurch,New Zealand: Practical and Policy Implications

Natural disasters greatly impact the environment of affected societies with often unknown consequences. In this study we examine the impact that the Canterbury Earthquakes of 2010–2011 had on the distribution of alcohol outlets in Christchurch, New Zealand. Specifically, we compare the distribution of both on-site and off-site alcohol outlets pre- (December 2009) and post-earthquake (December 2014) and use spatial regression models to identify whether any neighbourhood-level factors predict the observed redistributions. Overall, the number of alcohol outlets decreased by almost 13% after the Canterbury Earthquakes. However, we found a moderate increase in the clustering of both outlet types of outlets in the post-quake period. Increases in rates of both on-site and off-site alcohol outlets in neighbourhoods were positively associated with the percentage of residents who resided in their neighbourhood < 5 years and with neighbourhood crime rate change, while negative associations were found with percentage population aged between 15 and 29 years. The results suggest that the changing spatial distribution of alcohol outlets in Christchurch was not random but driven, in part, by the emergent demographic composition of neighbourhoods. The significant practical and policy implications of a redistribution of alcohol outlets are outlined providing a tangible link between empirical research and practice in an urban environment plagued with post-disaster spatial and social uncertainties.     

Temporal variations and spatial distribution of ambient PM2.2 and PM10 concentrations in Dhaka, Bangladesh

Concentrations and characteristics of airborne particulate matter (PM(10), PM(2.2) and BC) on air quality have been studied at two air quality-monitoring stations in Dhaka, the capital of Bangladesh. One site is at the Farm Gate area, a hot spot with very high pollutant concentrations because of its proximity to major roadways. The other site is at a semi-residential area located at the Atomic Energy Centre, Dhaka Campus, (AECD) with relatively less traffic. The samples were collected using a 'Gent' stacked filter unit in two fractions of 0-2.2 mum and 2.2-10 mum sizes. Samples of fine (PM(2.2)) and coarse (PM(2.2-10)) airborne particulate matter fractions collected from 2000 to 2003 were studied. It has been observed that fine particulate matter has a decreasing trend, from prior year measurements, because of Government policy interventions like phase-wise plans to take two-stroke three-wheelers off the roads in Dhaka and finally banned from January 1, 2003. Other policy interventions were banning of old buses and trucks to ply on Dhaka city promotion of the using compressed natural gas (CNG), introducing air pollution control devices in vehicles, etc. It was found that both local (mostly from vehicular emissions) and possibly some regional emission sources are responsible for high PM(2.2) and BC concentrations in Dhaka. PM(2.2), PM(2.2-10) and black carbon concentration levels depend on the season, wind direction and wind speed. Transport related emissions are the major source of BC and long-range transportation from fossil fuel related sources and biomass burning could be another substantial source of BC.     

新西兰基督城搅拌站的生产与绿色环保理念

结合新西兰基督城ASHBY’S搅拌站的安全规范,从作息时间、绿色环保、节能与交通运输三方面,论述了该搅拌站的生产理念,并对其整个运行系统及管理模式进行了介绍,指出ASHBY’S搅拌站绿色环保、人性化管理的生产理念值得借鉴学习。     

Temporary urbanism and urban sustainability after a natural disaster: transitional community-initiated open spaces in Christchurch,New Zealand

Temporary uses of vacant urban spaces are usually not foreseen in conventional urban planning and have often been linked to economic or political disturbances. In New Zealand, Christchurch’s vacant spaces came into existence after the city was hit by several devastating earthquakes in 2010 and 2011. Parallel to the ‘official’ rebuild discourse, temporary uses have emerged on vacant post-earthquake sites including community gardens, urban agriculture, art installations, event venues, eateries and cafés, and pocket parks. Based on the review and analysis of exemplary transitional community-initiated open spaces and correlated literature, the paper looks at how the post-disaster urban context in Christchurch has influenced particular aspects of temporary urbanism in comparison with case studies in non-disaster environments. By focusing on the anticipated benefits of community-initiated open spaces, the paper discusses the relevance of temporary uses of vacant urban spaces for urban sustainability in relationship to concepts of community resilience and raises questions about possible long-term values.     

Comparison of next-generation portable pollution monitors to measure exposure to PM2.5 from household air pollution in Puno,Peru

Assessment of personal exposure to PM_2.5 is critical for understanding intervention effectiveness and exposure-response relationships in household air pollution studies. In this pilot study, we compared PM_2.5 concentrations obtained from two next-generation personal exposure monitors (the Enhanced Children MicroPEM or ECM; and the Ultrasonic Personal Air Sampler or UPAS) to those obtained with a traditional Triplex Cyclone and SKC Air Pump (a gravimetric cyclone/pump sampler). We co-located cyclone/pumps with an ECM and UPAS to obtain 24-hour kitchen concentrations and personal exposure measurements. We measured Spearmen correlations and evaluated agreement using the Bland-Altman method. We obtained 215 filters from 72 ECM and 71 UPAS co-locations. Overall, the ECM and the UPAS had similar correlation (ECM ρ = 0.91 vs UPAS ρ = 0.88) and agreement (ECM mean difference of 121.7 µg/m³ vs UPAS mean difference of 93.9 µg/m³) with overlapping confidence intervals when compared against the cyclone/pump. When adjusted for the limit of detection, agreement between the devices and the cyclone/pump was also similar for all samples (ECM mean difference of 68.8 µg/m³ vs UPAS mean difference of 65.4 µg/m³) and personal exposure samples (ECM mean difference of −3.8 µg/m³ vs UPAS mean difference of −12.9 µg/m³). Both the ECM and UPAS produced comparable measurements when compared against a cyclone/pump setup.     

2,3,7,8-TCDD equivalence and mutagenic activity associated with PM10 from three urban locations in New Zealand

Ambient particulate matter (PM(10)) in urban centres varies depending on emission sources, geography, demography, and meteorology. Hence physical (PM(10), wind speed, rainfall, temperature), chemical (polycyclic aromatic hydrocarbons, PAH), and toxicological (Ames Test, H4IIE EROD Assay) analyses were done on daily PM(10) (approximately 1640 m(3)/day) collected from three New Zealand urban sites where winter emissions were predominantly due to domestic home heating. Daily PM(10) levels ranged between 9.7 and 20.8 in summer and between 21.8 and 61.0 microg/m(3) in winter. Daily PAH concentrations were 0.5, 0.45, and 1.5 ng/m(3) in summer and 52.1, 128.9, and 5.8 ng/m(3) in winter at sites Christchurch, Alexandra and Dunedin, respectively. During winter, 74% of PM(10) extracts from all three sites showed significant mutagenicity in the Ames Test (TA 98, -S9), whereas approximately 25% of the daily PM(10) was mutagenic in summer. Benzo[a]pyrene and BaP carcinogenic equivalence concentrations during winter were strongly correlated to both mutagenicity and TCDD-like activity at two sites. Daily levels of TCDD toxicity equivalence concentrations ranged from 0.5 to 3.6 pg TCDD/m(3) air in summer and from 0.3 to 4009 pg TCDD/m(3) air in winter. Chemically and biologically derived TCDD toxicity equivalent concentrations were significantly correlated in all study locations indicating that PAH may represent most of the TCDD-like activity present in the PM(10).     

Temporal variations of PM2.5 in the ambient air of a suburban site in Athens, Greece

Twenty-three hour measurements of PM(2.5) particulate matter have been carried out during the period between the 1st April and the 13th November 2003 in a suburban area of Athens. The monitoring site was located in the National Research Center "DEMOKRITOS", on the foot of Hemittos Mountain and about 12 km away from the center of Athens. The site covers an area of 600 acres in a forest of pine trees close enough to the newly constructed Hemittos Mountain peripheral highway. PM(2.5) samples were collected on 47 mm filters, with the use of low volume gravimetric samplers while a meteorological station recorded meteorological data 6 m above the ground, nearby the sampling instrumentation. The daily average PM(2.5) concentration reached 21.1 microg m(-3) and all measurements were below U.S. Environmental Pollution Agency daily limit (65 microg m(-3)). A regression analysis was used to investigate the relationship among PM(2.5) concentrations and meteorological parameters. Additionally, PM(2.5) mass concentrations were correlated with other inorganic gaseous pollutants (O(3), NO, NO(2), SO(2)) while weekly and seasonal PM(2.5) variations were also investigated.     

Time-series studies on air pollution and daily outpatient visits for allergic rhinitis in Beijing, China

To investigate the effects of urban air quality change on health, we carried out a time-series analysis of daily general practitioner consultations for allergic rhinitis (AR) in Beijing, China. Non-parametric generalized additive model (GAM) was used to analyze the highly non-linear or non-monotonic exposure-response relationship between three air pollutants (namely PM₁₀, SO₂ and NO₂) and daily outpatient visits for AR, after controlling for long term trends, the ‘day of the week’ effect and confounding meteorological factors. The objective of this study was to assess the possible effects of air pollutants on outpatient visits caused by AR in Beijing during the period 2009-2010. Our work indicates that strong associations exist between daily concentration of the three air pollutants and the daily number of outpatients for AR.     

Chemical characterization of individual particles (PM10) from ambient air in Guiyang City, China

PM10 samples were collected during 5 days in Guiyang, China in July 2003. A total of about 2300 particles was analyzed by an automated Scanning Electron Microscope with Energy-Dispersive Spectrometer (SEM-EDS). Hierarchical cluster analysis (HCA) was used to identify different particle types that occurred in the aerosol. Seventeen particle types were identified and presented in the order of decreasing number abundance as: silicomanganese slag, soil and fly ash, coal burning, silicomanganese, quartz, syngenite, S-bearing iron, calcium rich, gypsum, sphalerite, dolomite, iron, alloy, lead sulfate, zinc rich, sulfur-rich particles and aluminum manufacturing dust. The majority of the particles in the studied size range are of anthropogenic origin, especially from metallurgical industry. The study illustrates the complexity of particle pollution in air of an industrial Chinese city and the results should be useful in planning mitigation measures.     

Performance evaluation of air quality models for predicting PM10 and PM2.5 concentrations at urban traffic intersection during winter period

There are several models that can be used to evaluate roadside air quality. The comparison of the operational performance of different models pertinent to local conditions is desirable so that the model that performs best can be identified. Three air quality models, namely the 'modified General Finite Line Source Model' (M-GFLSM) of particulates, the 'California Line Source' (CALINE3) model, and the 'California Line Source for Queuing & Hot Spot Calculations' (CAL3QHC) model have been identified for evaluating the air quality at one of the busiest traffic intersections in the city of Guwahati. These models have been evaluated statistically with the vehicle-derived airborne particulate mass emissions in two sizes, i.e. PM10 and PM2.5, the prevailing meteorology and the temporal distribution of the measured daily average PM10 and PM2.5 concentrations in wintertime. The study has shown that the CAL3QHC model would make better predictions compared to other models for varied meteorology and traffic conditions. The detailed study reveals that the agreements between the measured and the modeled PM10 and PM2.5 concentrations have been reasonably good for CALINE3 and CAL3QHC models. Further detailed analysis shows that the CAL3QHC model performed well compared to the CALINE3. The monthly performance measures have also led to the similar results. These two models have also outperformed for a class of wind speed velocities except for low winds (<1 m s(-1)), for which, the M-GFLSM model has shown the tendency of better performance for PM10. Nevertheless, the CAL3QHC model has outperformed for both the particulate sizes and for all the wind classes, which therefore can be optional for air quality assessment at urban traffic intersections.     

The biofiltration of indoor air: implications for air quality

An alternative method of maintaining indoor air quality may be through the biofiltration of air recirculating within the structure rather than the traditional approach of ventilation. This approach is currently being investigated. Prior to its acceptance for dealing with volatile organic compounds (VOCs) and CO2, efforts were made to determine whether the incorporation of this amount of biomass into the indoor space can have an (negative) impact on indoor air quality. A relatively large ecologically complex biofilter composed of a ca. 10 m2 bioscrubber, 30 m2 of plantings and a 3,500 litre aquarium were established in a 160 m2 'airtight' room in a recently constructed office building in downtown Toronto. This space maintained ca. 0.2 air changes per hour (ACH) compared to the 15 to 20 ACH (with a 30% refresh rate) of other spaces in the same building. Air quality parameters of concern were total VOCs (TVOCs), formaldehyde and aerial spore counts. TVOC and formaldehyde levels in the biofilter room were the same or significantly less than other spaces in the building despite a much slower refresh rate. Aerial spore levels were slightly higher than other indoor spaces but were well within reported values for 'healthy' indoor spaces. Levels appeared to be dependent on horticultural management practices within the space. Most genera of fungal spores present were common indoors and the other genera were associated with living or dead plant material or soil. From these results, the incorporation of a large amount of biomass associated with indoor biofilters does not in itself lower indoor air quality.     

Urban Intensification in Auckland,New Zealand: A Challenge for New Urbanism

Medium Density Housing (MDH) is a relatively new form of housing in New Zealand where the standalone house on a separate lot has traditionally been revered. This paper reports on the findings of a research project on Ambrico Place, a major MDH initiative in Waitakere City, one of four cities in the Auckland metropolitan area. This case study explores the development of a site that has been significantly influenced by new urbanist principles. The paper provides an overview of the historical and political context influencing the take up of MDH in Auckland. It briefly reviews theory and principles arising from new urbanist movements then describes the Ambrico Place Research Project. Next, it explores three interrelated issues, relevant to new urbanism, that arose from the research; the quality of the built environment, community and social interaction, and transport patterns of MDH residents. Implications for planning are identified. Finally, three problems are noted: the uncritical and incoherent implementation of new urbanist principles; the contradiction between the drives for both diversity and homogeneity in the built environment; and the tensions arising from the application of an environmental effects-based approach to planning in an urban setting.     

Decision support system for the evaluation of urban air pollution control options: Application for particulate pollution in Thessaloniki, Greece

Development of strategies to control urban air pollution is a complex and multi-disciplinary process involving a wide range of scientists with different expertise and interests. This paper presents an integrated assessment methodological scheme for the evaluation of air pollution control measures that are put forward in order to reduce sufficiently air pollution levels in urban areas. Forming long-term, efficient air pollution control strategies requires knowledge of the costs associated with their implementation, the emission inventories and emission reductions to be achieved, as well as the concentration variations that represent air quality levels in the area examined. In contrast to the majority of the currently employed assessment approaches, the presented scheme enables the evaluation of any proposed air pollution control option in terms of its combined impact on air quality and social welfare, by correlating economic and health impact assessment issues. The approach presented in this paper brings together air quality modelling and mathematical programming techniques and provides a decision support system for the determination of optimal bundles of air pollution control options according to the particular features and needs of the areas examined. Both cost-effectiveness and cost–benefit approaches are taken into account in order to put the problem on the basis of economic efficiency from a societal perspective. The methodology is implemented for the case of Thessaloniki, Greece, which is selected on the grounds that the area is considered as one of the most polluted—if not the most polluted—cities within Europe, especially with respect to airborne particles.     

Indoor air pollution in developing countries: recommendations for research

Available studies indicate that indoor air pollution (IAP) from household cooking and space heating apparently causes substantial ill-health in developing countries where the majority of households rely on solid fuels (coal or biomass as wood, crop residues, and dung), but there are many remaining uncertainties. To pin down impacts in order to effectively target interventions, research is particularly needed in three areas: (1) epidemiology: case-control studies for tuberculosis (TB) and cardiovascular disease in women and randomized intervention trials for childhood acute respiratory diseases and adverse pregnancy outcomes; (2) exposure assessment: techniques and equipment for inexpensive exposure assessment at large scale, including national level surveys; (3) interventions: engineering and dissemination approaches for improved stoves, fuels, ventilation, and behavior that reliably and economically reduce exposure. There are also important potential synergisms between efforts to reduce greenhouse gas emissions and those to reduce health-damaging emissions from solid-fuel stoves. The substitution of biomass by coal being considered in some countries should be pursued with caution because of the known serious health effects of household coal use.     

Statistical studies of mortality and air pollution: Multiple regression analyses stratified by age group

Multiple regression analyses are presented relating age-specific mortality rates for up to 158 U.S. cities for 1969–1971 to community air pollution and socioeconomic variables, including an index of cigarette smoking. The results showed that excess mortality was associated with concentrations of airborne manganese and, to a lesser extent, total suspended particulates (TSP). The associations tended to be stronger for the older age groups (>65).In exploring these associations further, it was shown that the regression results were not inconsistent with a lag effect, i.e., that pollution from a 10 year or more earlier time period was implicated. Analysis for pollutant thresholds indicated none for manganese, but the suggestion of a no-effect threshold for TSP at 85–130 μg/m³.In contrast to some previous studies by other authors, no consistent (positive) associations were found between excess mortality and suspended sulfates.