Aerosol optical depth, aerosol composition and air pollution during summer and winter conditions in Budapest

The dependence of aerosol optical depth (AOD) on air particulate concentrations in the mixing layer height (MLH) was studied in Budapest in July 2003 and January 2004. During the campaigns gaseous (CO, SO(2), NO(x), O(3)), solid components (PM(2.5), PM(10)), as well as ionic species (ammonium, sulfate and nitrate) were measured at several urban and suburban sites. Additional data were collected from the Budapest air quality monitoring network. AOD was measured by a ground-based sun photometer. The mixing layer height and other common meteorological parameters were recorded. A linear relationship was found between the AOD and the columnar aerosol burden; the best linear fit (R(2)=0.96) was obtained for the secondary sulfate aerosol due to its mostly homogeneous spatial distribution and its optically active size range. The linear relationship is less pronounced for the PM(2.5) and PM(10) fractions since local emissions are very heterogeneous in time and space. The results indicate the importance of the mixing layer height in determining pollutant concentrations. During the winter campaign, when the boundary layer decreases to levels in between the altitudes of the sampling stations, measured concentrations showed significant differences due to different local sources and long-range transport. In the MLH time series unexpected nocturnal peaks were observed. The nocturnal increase of the MLH coincided with decreasing concentrations of all pollutants except for ozone; the ozone concentration increase indicates nocturnal vertical mixing between different air layers.     

2002 summer fires in Lithuania: impact on the Vilnius city air quality and the inhabitants health

The episodes with highly elevated concentrations of particulate matter (PM10), NOx, and CO were detected in the city of Vilnius between August and September 2002 and possible reasons were analysed. This increase was attributed to emissions from fires in the vicinity of the city of Vilnius when data on fire location and start, wind direction and concentrations of pollutants were analysed. The correlation coefficient between PM10 and CO, NO, NO2, NOx increased during the fire period in comparison with the same correlation after the fire period. During the fire episodes, there was an increase in concentration of ozone precursors, and meteorological conditions were favourable for photochemical reactions. Therefore, the hourly values for ozone exceeded the values common for Vilnius. Generally, during the episodes, the maximum of NO2 concentrations was 2 times higher than the limit value for NO2 laid down in the Council Directives 1999/30/EC [Council Directive 1999/30/EC of 22 April 1999 relating to limit values for sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter and lead in ambient air. Official Journal L 163, 29/06/1999: 0041-0060], and that of PM10 was even 5.5 times higher than the limit value for PM10. Human health effects study in Vilnius indicated that the incidents of documented respiratory diseases and exacerbation of the bronchial asthma during the fire period were up to 20 times higher in comparison to periods with no fires.     

Effectiveness of Portable Indoor Air Cleaners: Sensory Testing Results

The objective of this study was to test the effectiveness of individual commercially available portable indoor air cleaning units in removing dust particulates, tobacco smoke particulate and vapor phase constituents (nicotine and vinyl pyridine), viable and total fungal spores, pollen, and gaseous contaminants (carbon monoxide[CO], nitrogen dioxide[NO²], and formaldehyde[HCHO]), in a clean air test chamber. The air cleaner chamber results presented here represent initial-use results. In general, High Efficiency Particulate Air (HEPA) and electrostatic precipitator systems demonstrated the highest efficiencies with respect to particulate, contaminants, followed closely by electret filter systems. Ionizers and ozone generators were least effective in particulate removal. Systems which included sufficient sorbent material (i.e. activated carbon or potassium permanganate) were marginally effective at gaseous contaminant removal. None of the systems tested were effective at carbon monoxide removal. Sensory testing was conducted to discern potential correlation between human perceptive response and measured air cleaner performance (with respect to tobacco smoke removal). An electret filter (EF) loaded with carbon sorbent received the best ratings with respect to odor strength, nasal irritation, eye irritation, and overall air acceptability.     

Effects of an ozone-generating air purifier on indoor secondary particles in three residential dwellings

The use of indoor ozone generators as air purifiers has steadily increased over the past decade. Many ozone generators are marketed to consumers for their ability to eliminate odors and microbial agents and to improve health. In addition to the harmful effects of ozone, recent studies have shown that heterogeneous and homogeneous reactions between ozone and some unsaturated hydrocarbons can be an important source of indoor secondary pollutants, including free radicals, carbonyls, carboxylic acids, and fine particles. Experiments were conducted in one apartment and two detached single-family dwellings in Austin, TX, to assess the effects of an ozone generator on indoor secondary organic aerosol concentrations in actual residential settings. Ozone was generated using a commercial ozone generator marketed as an air purifier, and particle measurements were recorded before, during, and after the release of terpenes from a pine oil-based cleaning product. Particle number concentration, ozone concentration, and air exchange rate were measured during each experiment. Particle number and mass concentrations increased when both terpenes and ozone were present at elevated levels. Experimental results indicate that ozone generators in the presence of terpene sources facilitate the growth of indoor fine particles in residential indoor atmospheres. Human exposure to secondary organic particles can be reduced by minimizing the intentional release of ozone, particularly in the presence of terpene sources. PRACTICAL IMPLICATIONS: Past studies have shown that ozone-initiated indoor chemistry can lead to elevated concentrations of fine particulate matter, but have generally been completed in controlled laboratory environments and office buildings. We explored the effects of an explicit ozone generator marketed as an air purifier on the formation of secondary organic aerosol mass in actual residential indoor settings. Results indicate significant increases in number and mass concentrations for particles <0.7 microns in diameter, particularly when an ozone generator is used in the presence of a terpene source such as a pine oil-based cleaner. These results add evidence to the potentially harmful effects of ozone generation in residential environments.     

Particulate exposure and size distribution from wood burning stoves in Costa Rica

Biomass fuel is the most common energy source for cooking and space heating in developing countries. Biomass fuel combustion causes high levels of indoor air pollutants including particulates and other combustion by-products. We measured indoor air quality in 23 houses with a wood burning stove in rural residential areas of Costa Rica. Daily PM2.5, PM10 and CO concentrations, and particle size distribution were simultaneously measured in the kitchen. When a wood burning stove was used during the monitoring period, average daily PM2.5 and PM10 concentrations were 44 and 132 microg/m3, respectively. Average CO concentrations were between 0.5 and 3.3 ppm. All houses had a particle size distribution of either one or two peaks at around 0.7 and 2.5 microm aerodynamic diameters. The particulate levels increased rapidly during cooking and decreased quickly after cooking. The maximum peak particulate levels ranged from 310 to 8170 microg/m3 for PM2.5 and from 500 to 18900 microg/m3 for PM10 in all houses. Although the 24-h particulate levels in this study are lower than the National Ambient Air Quality Standards of PM2.5 and PM10, it is important to note that people, especially women and children, are exposed to extremely high levels of particulates during cooking.     

Indoor air quality for chemical and ultrafine particle contaminants from printers

There are various emission sources of chemical contaminants, such as volatile organic compounds (VOCs) and ozone and particulate matter. This report is a study into the indoor air of a room containing either a laser printer/ink-jet printer, and the air contaminations were monitored for VOCs, ozone and ultrafine particle. The result confirmed an increase in the concentration of ozone and ultrafine particle numbers in the printing processes of the printer. The emission of VOCs and ozone were measured by the use of a test chamber. The chamber concentrations of styrene, xylenes and ozone were increased in printing process of the laser printer, and pentanol was detected from the ink-jet printer. The results suggest that an office or residential printer may be a source of indoor air contamination. It is necessary for emission from printers to monitor not only VOCs and particle but also ultrafine particles and other contaminants in indoor air.     

Mercury in the river mersey, its estuary and tributaries during 1973 and 1974

Mercury levels found in waters and suspended matter from 53 stations, occupied four times at 3-monthly intervals, showed that most mercury was associated with particulates but the amount varied during the year. In the polluted region between Warrington and Runcorn, where fresh-water and sea-water converge, >80% of the mercury was associated with the particulates. Dissolved mercury concentrations and the mercury load on particulate matter were always greater in freshwater than in tidal waters, except during a flood. A model of partitioning of mercury between particulate and dissolved phases is presented. The River Weaver and the Manchester Ship Canal were grossly polluted with mercury throughout that year due to a Castner-Kelner plant at Runcorn. Dredge spoils and water flow transport 17 (range 8–138) and 1.55 ± 65% tonnes yr⁻¹ respectively of mercury into Liverpool Bay.     

The relationship between particulate air pollution and emergency hospital visits for hypertension in Beijing, China

Background

A number of epidemiological studies have examined the adverse effect of air pollution on mortality and morbidity. Also, several studies have investigated the associations between air pollution and specific-cause diseases including arrhythmia, myocardial infarction, and heart failure. However, little is known about the relationship between air pollution and the onset of hypertension.

Objective

To explore the risk effect of particulate matter air pollution on the emergency hospital visits (EHVs) for hypertension in Beijing, China.

Methods

We gathered data on daily EHVs for hypertension, fine particulate matter less than 2.5 μm in aerodynamic diameter (PM_2.5), particulate matter less than 10 μm in aerodynamic diameter (PM₁₀), sulfur dioxide, and nitrogen dioxide in Beijing, China during 2007. A time-stratified case-crossover design with distributed lag model was used to evaluate associations between ambient air pollutants and hypertension. Daily mean temperature and relative humidity were controlled in all models.

Results

There were 1,491 EHVs for hypertension during the study period. In single pollutant models, an increase in 10 μg/m³ in PM_2.5 and PM₁₀ was associated with EHVs for hypertension with odds ratios (overall effect of five days) of 1.084 (95% confidence interval (CI): 1.028, 1.139) and 1.060% (95% CI: 1.020, 1.101), respectively.

Conclusion

Elevated levels of ambient particulate matters are associated with an increase in EHVs for hypertension in Beijing, China.     

Wood stove use and other determinants of personal and indoor exposures to particulate air pollution and ozone among elderly persons in a Northern Suburb

A six‐month winter‐spring study was conducted in a suburb of the northern European city of Kuopio, Finland, to identify and quantify factors determining daily personal exposure and home indoor levels of fine particulate matter (PM_2.5, diameter <2.5 µm) and its light absorption coefficient (PM_2.5abs), a proxy for combustion‐derived black carbon. Moreover, determinants of home indoor ozone (O₃) concentration were examined. Local central site outdoor, home indoor, and personal daily levels of pollutants were monitored in this suburb among 37 elderly residents. Outdoor concentrations of the pollutants were significant determinants of their levels in home indoor air and personal exposures. Natural ventilation in the detached and row houses increased personal exposure to PM_2.5, but not to PM_2.5abs, when compared with mechanical ventilation. Only cooking out of the recorded household activities increased indoor PM_2.5. The use of a wood stove room heater or wood‐fired sauna stove was associated with elevated concentrations of personal PM_2.5 and PM_2.5abs, and indoor PM_2.5abs. Candle burning increased daily indoor and personal PM_2.5abs, and it was also a determinant of indoor ozone level. In conclusion, relatively short‐lasting wood and candle burning of a few hours increased residents’ daily exposure to potentially hazardous, combustion‐derived carbonaceous particulate matter.     

Filter backwash and start-up strategies for enhanced particulate removal

A significant consideration in forward planning for water treatment works design and operation concerns the effectiveness of a filtration plant in providing a barrier to particulates in the low micrometre size range, including Cryptosporidium oocysts. The performance of rapid gravity filtration plants is believed to be dependent on backwash and start-up regimes. It was the aim of this study to optimize direct sand filtration by identifying optimum filter backwash and start-up conditions which minimized the passage of particulates into the filtrate. The filter ripening period has long been identified as a cause for concern with respect to particulate passage into the filtrate; this work has shown that up to 40% of all particles that pass into supply during a 48 h run, do so in the first hour of operation. Optimum combined air water “collapse-pulsing” backwash durations were identified that reduced the number of 2–5 μm particles entering the filtrate, especially during the ripening period. Slow start-up was also found to reduce the number of 2–5 μm particles in the filtrate during the ripening period. The reductions in particulate passage resulting from a slow start was found to be media dependent, with smaller media requiring a longer slow start duration than coarser media.     

The effect of an ion generator on indoor air quality in a residential room

Ion generators charge particles with a corona prior to their removal on collector plates or indoor surfaces and also emit ozone, which can react with terpenes to yield secondary organic aerosol, carbonyls, carboxylic acids, and free radicals. This study characterized the indoor air quality implications of operating an ion generator in a 27 m(3) residential room, with four different test room configurations. Two room configurations had carpet overlaying the original flooring of stained/sealed concrete, and for one configuration with and without carpet, a plug-in air freshener was used as a terpene source. Measurements included airborne sampling of particulate matter (0.015-20 μm), terpenes and C(1) -C(4) and C(6) -C(10) aldehydes, ozone concentrations, and air exchange rates. When the heating, ventilating, and air-conditioning system was not operating (room air exchange rate = ～0.5/h), the use of the ion generator in the presence of the air freshener led to a net increase in ultrafine particles (<0.1 μm). Also, increased concentrations of ozone were observed regardless of air freshener presence, as well as increases in formaldehyde and nonanal, albeit within measurement uncertainty in some cases. Thus, it may be prudent to limit ion generator use indoors until evidence of safety can be ascertained. PRACTICAL IMPLICATIONS: Portable ion generators are intended to clean the air of particles, but they may emit ozone as a byproduct of their operation, which has the potential to degrade indoor air quality. This study showed that under certain conditions in a residential room, the use of a portable ion generator can increase concentrations of ozone and, to a lesser degree, potentially aldehydes. Also, if operated in the presence of a plug-in air freshener that emits terpenes, its use can increase concentrations of secondary organic aerosol in the ultrafine size range.     

Effects of air purification of indoor PM2.5 on the cardiorespiratory biomarkers in young healthy adults

Ambient fine particulate matter (PM_2.5), as one of the predominant air pollutants, has achieved effective control in recent years in China. Whether the use of indoor air purifiers is still necessary needs further exploration. A randomized crossover trial was conducted in 54 healthy students in Beijing, China. Participants were randomized assigned to the use of real or sham high-efficiency particulate air filter (HEPA) for a week and changed the status after a washout period. Health measurements of cardiorespiratory biomarkers were performed at the end of each period. Linear mixed-effects models were used to evaluate the association between PM_2.5 exposure and cardiorespiratory biomarkers. Compared with sham air purification, average diastolic blood pressure (DBP), fractional exhaled nitric oxide (FeNO), and 8-isoprostane (8-isoPGF2α) levels decreased significantly in the real purification. The effects of indoor air purification on lung function indicators including forced expiratory volume in one second (FEV₁), peak expiratory flow (PEF), and forced expiratory flow between the 25th and 75th percentile of forced vital capacity (FEF_25%–75%) were also significant. Our findings showed a protective effect of indoor HEPA air purifiers on cardiorespiratory health of young healthy adults reflected by the decreased blood pressure, respiratory inflammation, and systematic oxidative stress and improved lung function.     

Survey of total and respirable suspended particulate matter in an iron foundry. Comparison of stationary sampling and personal monitoring

In the workshop of an iron foundry total and respirable suspended particulate matter was collected. The performances of (1) filtration systems with 47 mm membrane filters, (2) Andersen cascade impactors, and (3) personal total or respirable monitoring, were compared at a position away from intense sources of particulate debris.Using 15 stationary samplers a survey was made of the particulate levels in the workshop, over a period of 2 weeks. Very large concentration gradients and concentration variations as a function of time were measured for total suspended particulate matter.In the three major source areas, i.e. the pouring department, the core-making department and the shake-out department, special studies were performed to compare stationary and personal monitoring.In the immediate vicinity of intense point sources of coarse particles, such as core-making or shake-out, stationary sampling cannot be used to estimate the personal exposure to total suspended particulates. For respirable particles, however, one or two well-situated stationary size-selective samplers can provide a good estimate of the personal exposure as measured with a personal respirable monitor. The differences found are in the order of 10–20%.     

Asian Dust Storm and pulmonary function of school children in Seoul

Health effects of the Asian Dust Storm (ADS) have not been evaluated adequately, even though it may affect health of people in East Asia. This study was conducted to evaluate whether the ADS affects particulate air pollution and pulmonary function of children. We studied 110 school children in Seoul, Korea with daily measurement of peak expiratory flow rate (PEFR) from May 13 to June 15, 2007. PM_2.5, PM₁₀ and metals bound to the particles were also determined daily during the study period in Ala Shan and Beijing (China) as well as in Seoul (Korea). Three-day back trajectories showed that air parcels arrived at Seoul mostly from the desert areas in China and Mongolia through eastern China during ADS event affecting levels of particulate pollutants in the areas. Analysis of metals bound to the particulates showed that natural metal levels were much higher than the anthropogenic metal levels. We found that ambient concentrations of PM_2.5 and PM₁₀ were not significantly associated with PEFR in school children except asthmatics during the study period (P > 0.05). However, most of the metal concentrations bound to the particulates were significantly associated with decrease of the children's PEFR (P < 0.05). The effect of anthropogenic metals was not different from natural components of metals for reduction of PEFR. This result indicates that exposure to the metals bound to particles during the ADS period reduces children's pulmonary function, but there was no difference of potency for reduction of the pulmonary function between natural and anthropogenic metal components.     

Neighborhood Air Quality,Respiratory Health,and Vulnerable Populations in Compact and Sprawled Regions

Problem: Recently, public health researchers have argued that infill development and sprawl reduction may improve respiratory outcomes for urban residents, largely by reducing vehicle travel and its attendant mobile-source emissions. But infill can also increase the number of residents exposed to poor air quality within central cities. Aside from emissions studies, planners have little information on the connections between urban form, ambient pollutant levels, and human exposures or how infill changes these.

Purpose: We examined neighborhood exposures in 80 metropolitan areas in the United States to address whether neighborhood-level air quality outcomes are better in compact regions than in sprawled regions.

Methods: We used multilevel regression models to find the empirical relationship between a measure of regional urban form and neighborhood air quality outcomes.

Results and conclusions: Ozone concentrations are significantly lower in compact regions, but ozone exposures in neighborhoods are higher in compact regions. Fine particulate concentrations do not correlate significantly with regional compactness, but fine particulate exposures in neighborhoods are also higher in compact regions. Exposures to both ozone and fine particulates are also higher in neighborhoods with high proportions of African Americans, Asian ethnic minorities, and poor households.

Takeaway for practice: Compact development and infill do not solve air quality problems in all regions or for all residents of a given region. Planners should take differences in neighborhood air quality and human exposure into account when planning for new compact developments rather than just focusing on emissions reductions.

Research support: This project was supported by a grant from the ShenAir Institute at James Madison University and by the National Oceanographic and Atmospheric Administration.     

Interactions of silver with wastewater constituents

The interactions of silver ion with wastewater constituents including chloride, sludge particulates, and dissolved organic matter (DOM) were investigated using fresh and processed sludge samples from various municipal wastewater treatment plants. Fresh sludge samples were used to examine the silver removal characteristics in the presence of chloride. Processed sludge samples that were subjected to a deionized-water washing procedure to remove the chloride ion were used to examine the interactions among Ag(I), sludge solids, and DOM. Results showed that, under field conditions, most of the silver can be removed through precipitation with chloride and adsorption by sludge particulates. Results obtained using washed sludge samples showed that Ag(I) adsorption by sludge particulates increases with the increase of pH in the acidic pH range, but decreases with the increase of pH in the alkaline pH range. Since the DOM concentration increases significantly with the increase of pH in the alkaline pH region, it can be concluded that the formation of Ag(I)-DOM complexes reduces the Ag(I) adsorption by sludge. Fitting of the Langmuir isotherm to the adsorption data indicated that adsorption constants have a slight increase with the increase of pH in the acidic pH range, but decrease significantly with the increase of pH in the alkaline pH range. The decrease of the Ag(I) adsorption constants in the alkaline pH range can be attributed to the formation of Ag(I)-DOM complexes which weaken the Ag(I) binding strength by sludge surface sites. The fitted isotherms also showed that the Ag(I) adsorption capacity increases with the increase of pH in the entire pH range.     

Chemistry and nanoparticulate compositions of a 10,000 year-old ice core melt water

Particulates extracted from a single section of a 10,000 year-old ice core melt sample exhibited characteristics of contemporary, airborne fine particulates: a majority were microcrystalline particulates and aggregated microcrystals, including some mixtures of microcrystals and carbonaceous matter. Particularly significant were the presence of carbon nanotubes and fullerene nanocrystals composing aggregated particulates reflecting global combustion products similar to contemporary, airborne carbon nanocrystal aggregates. ICP elemental analysis of the melt water showed significant concentrations of Ca, K and especially Na (corresponding to K, NaCl), S, Si, Se, and Zn. Overall, the elemental analysis of the melt water is similar to local tap water. However, lead was absent in the local tap water and only half the concentration of selenium was present in the tap water in contrast to the ice core water. While these observations cannot be generalized, the methodology illustrates the potential to characterize and compare airborne particulate regimes and water chemistries in antiquity.     

Heavy metals in Lake Balaton: water column, suspended matter, sediment and biota

During the period 1999-2002, five sampling cruises have been carried out on Lake Balaton to assess trace metal distribution in the lake and to identify major sources. Eighteen elements, including Cr, Co, Ni, Cu, Zn, Cd, Pb (trace metals) and Al, Ba, Ca, Fe, K, Mg, Mn, Na, P, S, Sr (major metals), were determined in one or more of the lake's compartments. Lower trace metal concentrations in rainwater were observed in June and February 2000, while much higher levels were present in September 2001 (during a storm event) and in snow (February 2000). In the Northern and Western parts of the lake, especially at the inflow of river Zala and the locations of the yacht harbours, metal concentrations were higher in almost all compartments. Because the lake is very shallow, storm conditions also change significantly the metal distributions in the dissolved and particulate phases. The Kis-Balaton protection system located on Zala river functions very efficiently for retaining suspended particulate matter (SPM; 72% retention) and associated metals. Metal concentrations in surface sediments of the lake showed a high variability. After normalisation for the fine sediment fraction, only a few stations including Zala mouth appeared to be enriched in trace metals. In zooplankton, Zn seemed to be much more elevated compared to the other trace metals. Based on the molar ratios of the trace metals in the various compartments and input flows of the lake, several trends could be deduced. For example, molar ratios of the trace metals in the dissolved and solid (suspended particulate matter and sediments) phases in the lake are fairly similar to those in Zala River.     

Composition, structure and size distribution of suspended particulates from the Rhine River

Fluvial suspended particulates collected from the Rhine River were investigated in terms of composition, structure and size distribution. Elemental analysis and Diffuse Reflectance Infrared Spectroscopy reveal that most particulate organic matter is formed from material derived from microorganisms. Transmission Electron Microscopy observations on resin-embedded samples and structural characterization from break-up experiments, show that fluvial particulate matter should be viewed as fractal aggregates organized by bacterial exopolymeric substances. The shape of particulate size distribution suggests that the formation and dynamics of suspended particulate matter are controlled mainly by physical processes. Finally, particulate growth and structure are consistent with a cluster-cluster aggregation scheme.     

Air quality status in Greater Thessaloniki Area and the emission reductions needed for attaining the EU air quality legislation

This paper aims at imprinting the urban air quality status and assessing the impact of various emission reduction scenarios on the photochemical and particulate matter air pollution levels in the Greater Thessaloniki Area, Greece. In particular, it is investigated under which conditions compliance with the EU air quality legislation can be achieved. For this purpose, the Ozone Fine Structure model is applied for a full calendar period (reference year 2002), as well as for specific scenarios, corresponding to predefined emission reductions for 2010. The model results for photochemical and particulate matter air pollution levels in 2002 agree fairly well with the observations. Predictions for 2010 indicate that significant improvement towards the EU legislation requirements can be achieved for certain emission reduction scenarios. However, an overall strategy will also have to include additional local scale measures.