Dispersion of sulphur dioxide around the thermal power plant at Ahmedabad,India

Air quality due to the release of sulphur dioxide from the thermal power plant within the city limits of Ahmedabad has been computed employing a point, area and line dispersion model. To estimate probable air quality, the meteorological data for 3 consecutive days in the middle of each month of 1983 is used. The concentration of sulphur dioxide is computed at a distance of every 500 m in 16 directions up to the city limit. The air quality in the worst case is estimated in downwind distances under unfavourable meteorological conditions.The probable zones of high concentrations of sulphur dioxide over residential, commercial and industrial areas of the city are below the ambient air quality standards set by the U.S. EPA in 1971 almost throughout the year. However, in the months of April and October the zone of high concentration (500 μg m⁻³) exceeds the EPA standard. Also, under the most unfavourable meteorological conditions, the estimated high ground-level concentration of sulphur dioxide can reach up to 1000 μg m⁻³ at a distance of 1.25 km from the thermal power plant. This may be attributed to the effect of fumigation.     

Monthly and seasonal trends of total suspended particulate matter and smoke concentration in industrial and residential areas in Cairo

Total suspended particulate (TSP) matter and smoke were investigated at Shoubra El-Kheima industrial area and El-Dokki residential area located in Cairo. TSP gave the highest monthly mean concentration in 2 years' study at Shoubra El-Kheima (895 μg m⁻³), nearly 12 times the geometrical mean of air quality standard (75 μg m⁻³). The corresponding figure at the residential area is 544 μg m⁻³, which is 7.3 concentrations during spring and lower during summer. Smoke concentration in the industrial area was nearly 1.4 and 1.2 times its concentration in the residential area during the 2 study years. Smoke concentration was found to be light to moderate during 86% of the days and heavy to extremely heavy during 14% of the days at the industrial area. The corresponding percentages for the residential area were 90% and 10% for light to moderate and heavy to extremely heavy, respectively.     

Characteristics of airborne particles inside southern California museums

The concentrations and chemical composition of suspended particulate matter were measured in both the fine and total size modes inside and outside five southern California museums over summer and winter periods. The seasonally averaged indoor/outdoor ratios for particulate matter mass concentrations ranged from 0.16 to 0.96 for fine particles and from 0.06 to 0.53 for coarse particles, with the lower values observed for buildings with sophisticated ventilation systems which include filters for particulate matter removal. Museums with deliberate particle filtration systems showed indoor fine particle concentrations generally averaging less than 10 μg m⁻³. One museum with no environmental control system showed indoor fine particle concentrations averaging nearly 60 μg m⁻³ in winter and coarse particle concentrations in the 30–40 μg m⁻³ range. Analyses of indoor vs outdoor concentrations of major chemical species indicated that indoor sources of organic matter may exist at all sites, but that none of the other measured species appear to have major indoor sources at the museums studied. Significant fractions of the dark-colored fine elemental (black) carbon and soil dust particles present in outdoor air are able to penetrate to the indoor atmosphere of the museums studied, and may constitute a soiling hazard to works of art displayed in museums.     

Factors affecting airborne monocyclic aromatic hydrocarbon uptake by plants

Three factors influencing foliar uptake of monocyclic aromatic hydrocarbons (MAHs; benzene, toluene, ethylbenzene, xylenes) in situ were investigated. The first factor, the plant species, was found to determine absorption pattern and concentrations. Secondly, time variation studies showed that response of leaf concentrations to small changes in air concentrations only occurs after several days or weeks, whereas adaptation to a much higher level of air pollution takes several months. Thirdly, MAH leaf concentrations were observed to be dependent on mean air pollution at the sampling site. Bioconcentration factors BCF_vs (g m⁻³ of wet leaf/g m⁻³ of air) for MAHs in Pseudotsuga menziesii (Mirb.) Franco leaves were determined to range from 2.7 × 10⁴ to 4.7 × 10⁵.     

Urban air pollution in Brazil: Acetaldehyde and other carbonyls

We have measured ambient levels of carbonyls in three major urban areas of Brazil: Sao Paulo, Rio de Janeiro and Salvador. The most abundant carbonyls were acetaldehyde (up to 63 μg m⁻³, or 35 ppb) followed by formaldehyde (up to 42 μg m⁻³, or 34 ppb), and acetone (up to 20 ppb). Levels of 10 other aliphatic and aromatic carbonyls were in the range 0–5 ppb. Total carbonyl concentrations were in the range 11–75 ppb. Indoor levels were also measured at several locations in Salvador. High levels of acetaldehyde, 430 μg m⁻³ or 240 ppb, were measured in a highway tunnel.Using carbonyl/CO concentration ratios, mobile source emissions of carbonyls are estimated for the Sao Paulo area. Ambient levels of acetaldehyde and acetaldehyde/formaldehyde concentration ratios in Brazil are compared to those for other urban areas, and are briefly discussed in relation with the large scale use of ethanol as a vehicle fuel.     

Spatial and temporal patterns in nitrogen dioxide concentrations in a hot desert region

This paper reports seasonal and spatial variations in the ambient air concentration of nitrogen dioxide throughout the State of Bahrain, from February to December 1992. Monitoring sites were chosen to include urban areas with high traffic density, suburban areas with low traffic density, commercial and industrial areas. Correlations between meteorological parameters and mean NO₂ concentrations were analysed, and NO₂ levels were only significantly correlated with temperature (r = 0.63). Only February, a winter month, showed a significantly lower concentration of NO₂ with an overall mean value of 23 μgm⁻³, whereas in August, a summer month, it was 33 μgm⁻³. The results revealed that in a hot region like Bahrain, NO₂ concentrations do not show significant monthly variations. Also summer-averaged NO₂ values exceeded corresponding spring and winter values. In cold regions opposite patterns were observed. Moreover, the results revealed significant spatial variations in NO₂ concentrations. In suburban areas with low traffic density, the overall mean NO₂ level was 15, with a range of 12–17 μg m⁻³, while in urban areas with high traffic density, the overall mean value was 52 with a range of 44–60 μg m⁻³. The mean NO₂ value in industrial sites with low traffic density was 21 with a range of 14–27 μg m⁻³, whereas in the same areas near major roads, it was 32 with a range of 31–32 μg m⁻³. These results indicate that automobiles exhaust are the dominant source of NO₂ in Bahrain. The highest NO₂ levels were found in roads with high traffic density, which are narrow, with several traffic lights and roundabouts, suggesting the effect of road geometry on NO₂ levels.     

The personal,indoor and outdoor concentrations of PM-10 measured in an industrial community during the winter

The concentrations of PM-10 were measured for 2 weeks in the winter of 1988 as part of the Total Human Environmental Exposure Study (THEES). Samples were taken simultaneously in a small city, Phillipsburg, NJ for outdoor and indoor microenvironments, and with personal monitors on non-smokers. There were four outdoor sites, eight indoor sites and fourteen individuals wearing personal monitors. The mean concentrations were 66, 48 and 42 μg m⁻³ for the personal, outdoor and indoor sites, respectively, with the personal samplers having 8.8% of the 24h averages above 150 μg m⁻³. The higher outdoor averages with respect to indoors were suspected to be related to more prevalent outdoor sources of coarse particles < 10 μm in diameter, and the lack of residential smokers to contribute to the indoor respirable subfraction. There was one day during the period when all the outdoor sites exceeded the 24 h PM-10 standard. Increased outdoor levels were also reflected in elevated indoor samples and the personal samples on that day. These would be a result of direct outdoor exposures and the penetration of outdoor PM-10 to the indoors.     

Air pollutant concentrations in Varanasi,India

This study reports the diurnal patterns in the concentrations of ozone (O₃), nitrogen dioxide (NO₂), sulphur dioxide (SO₂) and total suspended particulate matter (TSP) in the urban atmosphere of Varanasi city in India during 1989. The city was divided into five zones and three monitoring stations were selected in each zone.Ambient concentrations of NO₂ and SO₂ were maximum during winter but ozone and TSP concentrations were highest during summer. The measured maximum concentrations (2-h average) were 150 and 231 μg m⁻³ (0.078 and 0.086 ppm) for NO₂ and SO₂, respectively, for the winter season. Ozone and TSP concentrations reached a maximum of 160 (0.08 ppm) and 733 μg m⁻³, respectively, in the summer. NO₂ and SO₂ concentrations peaked in the morning and evening. Peak concentrations of O₃ occurred in the afternoon, generally between noon and 4 p.m. Maximum concentrations of O₃, NO₂, SO₂ and TSP were measured in zones I and II, and minimum in zone V.     

Monitoring GHG from manure stores on organic and conventional dairy farms

Organic farming methods are claimed to be more environmentally friendly than conventional methods and the EU MIDAIR project had an overall aim to compare emissions from organic dairy farming with conventional methods of milk production. Manure stores are the second largest source of methane emissions (after enteric fermentation) on European dairy farming.The aim of this project was to measure green house gas (GHG) emissions from manures in covered and uncovered slurry stores and farm yard manure (FYM) heaps. The chosen method for measuring these emissions was the tracer ratio method, using sulphur hexafluoride (SF₆) as the tracer gas, the limitations of this method prevented successful measurements being made on some of the stores and a modified method was used on the covered stores. The difference in concentration of the upwind and downwind samples and interfering sources were limiting factors. FYM emission measurements were successful only when the manure was stored indoors.Methane emissions were successfully measured over a 12 month period from the uncovered slurry stores. Emission rates from the uncovered slurry stores on the conventional farm and the organic farm ranged from 14.4 to 49.6 and from 12.4 to 42.3 g C m⁻³ d⁻¹, respectively, with the mean CH₄ emission rates of 35 and 26 g C m⁻³ d⁻¹. On both farms, nitrous oxide emissions were close to zero.Methane emissions measured from the indoor organic FYM in summer were 17.1 g C m⁻³ d⁻¹ and the nitrous oxide emission was 411 mg N m⁻³ d⁻¹.The covered slurry stores were in such close proximity to other GHG sources that the tracer ratio method was unsuitable and the air-injection method was adopted. The measured emissions from covered slurry stores of CH₄, CO₂ and NH₃ were, respectively, 14.9 g C m⁻³ d⁻¹, 12.9 g C m⁻³ d⁻¹ and 18.6 mg NH₃ m⁻² d⁻¹ of slurry in February and 12.0 g C m⁻³ d⁻¹, 9.5 g C m⁻³ d⁻¹ and 335 mg NH₃ m⁻² d⁻¹ slurry in March. No nitrous oxide production could be measured.     

Chlorinated organic compounds in the troposphere over the western North Atlantic Ocean measured by aircraft

Results of 32 individual flights during 1985, 1986 and 1988 using a King Air research aircraft over the western North Atlantic Ocean and the Adirondack Mountains are presented. Measurements were made for selected trace organic compounds including α- and γ-isomers of hexachlorocyclohexane (HCH), the summed isomers of α- and γ-chlordane, dieldrin and polychlorinated biphenyls (PCBs). The concentrations of compounds at altitudes of 300–10,000 ft indicate that these compounds were well mixed in the atmosphere and that for the most part, ground-level and higher-altitude concentrations were similar in magnitude. There was a high degree of variability due to time, meteorological events and location. Concentrations over the Adirondack Mountains in 1985 were the highest measured with means of 0.198 ng m⁻³ for HCB, 0.388 ng m⁻³ for α-HCH, 0.509 ng m⁻³ for γ-HCH, 0.340 ng m⁻³ for dieldrin, 0.480 ng m⁻³ for chlordane and 0.951 ng m⁻³ for total PCBs. Concentrations over the western North Atlantic south-east of Bermuda in summer 1988 wer lower, with means of 0.093 ng m⁻³ for HCB, 0.142 ng m⁻³ for α-HCH, 0.012 ng m⁻³ for γ-HCH, 0.016 ng m⁻³ for dieldrin 0.020 ng m⁻³ for chlordane and 0.600 ng m⁻³ for PCBs. During 1988 concentrations of most of the compounds were similar in the atmosphere of the coastal zone, 50–100 km off the U.S., to those measured near Bermuda. Chlordane, and to a lesser extent dieldrin, showed a decrease in concentration away from North America.     

Measured components in total suspended particulate matter in a Kenyan urban area

Nairobi city has a population of over 1.5 million and is growing at a rate of about 70 persons per day. Various activities in the city such as construction work, industrial processes, use of unroadworthy cars, and dust blown off unpaved roads contribute enormously to suspended particulate matter in the air. In this paper, analysis by gravimetric and energy dispersive X-ray fluorescence (EDXRF) of the suspended particulate matter in the air in the city centre, an industrial area and one residential area was carried out. The total suspended particulate matter (TSP) mean levels ranged from 69.983 to 397.903 μg m⁻³. The following components were measured from the TSP, mean values in μg m⁻³: iron 6.014–7.547, potassium 1.252–6.432, titanium 0.286–1.698, manganese 0.158–1.683, lead 0.395–1.321, bromine 0.122–0.707, zinc 0.159–0.678 and zirconium 0.017–0.245. The values of lead obtained (0.395–1.321 μg m⁻³) fall within the WHO recommendations, but compared to the values reported in some European countries, they are high. Most of the elements had low enrichment factors except for lead (104–353), bromine (429–1533) and zinc (14–79). Bromine and lead were highly correlated to the number of light vehicles (p=0.874 and 0.942, respectively). In addition the ratio of Br:Pb by weight was in the range 0.309–0.535, while the correlation factor for Br:Pb was 0.951, leading to the conclusion that both elements came from leaded gasoline.     

Unusually high indoor radon concentrations

Measurements of indoor radon concentrations in the village Umhausen (2600 inhabitants, Ötztal valley, Tyrol, Austria) revealed unusually high indoor radon concentrations up to 274,000 Bq m⁻³. The medians measured on the basements were 3750 Bq m⁻³ in winter and 361 Bq m⁻³ in summer, those on the ground floors were 1180 Bq m⁻³ and 210 Bq m⁻³, respectively. Seventy-one per cent of the houses showed basement radon concentrations above the Austrian action level of 400 Bq m⁻³ in winter, 33% in summer. There are indications that the high radon concentrations are due to a giant rock slide about 8700 years ago. The unusually high radon concentrations in Umhausen coincide with a statistically significant increase in lung cancer mortality. For the period 1970–1991 the age and sex standardized mortality rate is 3.85 (95% confidence interval: 2.9 to 5.1). The control population is the total population of Tyrol (630,000 inhabitants).     

Measurements of ammonia flux to a spruce stand in Denmark

This work demonstrates the existence of a linear relation between the deposition velocity of ammonia and the friction velocity measured above a spruce stand in the western part of Denmark. In order to estimate the ammonia deposition velocity and flux to a Norway spruce forest, concentration gradients of ammonia and several meteorological parameters were measured in a meteorology tower during two periods, 1 week in spring and 1 week in late summer 1991. The estimated deposition velocities lie in the range −0.125 to 0.201 m s⁻¹, with a mean of 0.026 m s⁻¹. The deposition velocity and the flux were generally largest in the afternoon. On the basis of 24-h measurements of ammonia and routine meteorological measurements the relation between deposition velocity and friction velocity is extrapolated to an estimate of the average flux for the growing season May to September 1991. The estimate gave an average flux of 87 μg NH₃N m⁻² h⁻¹ (=0.02 μg NH₃N m⁻² s⁻¹). The average deposition velocity for the period was 0.045 m s⁻¹.     

Trace metals in atmospheric fine particles in one industrial urban city: Spatial variations, sources, and health implications

Trace metals in PM2.5were measured at one industrial site and one urban site during September, 2010 in Ji'nan, eastern China. Individual aerosol particles and PM2.5samples were collected concurrently at both sites. Mass concentrations of eleven trace metals(i.e., Al, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Ba, and Pb) and one metalloid(i.e., As) were measured by inductively coupled plasma atomic emission spectroscopy(ICP-AES). The result shows that mass concentrations of PM2.5(130 μg/m3) and trace metals(4.03 μg/m3) at the industrial site were 1.3 times and 1.7 times higher than those at the urban site, respectively, indicating that industrial activities nearby the city can emit trace metals into the surrounding atmosphere. Fe concentrations were the highest among all the measured trace metals at both sites, with concentrations of 1.04 μg/m3at the urban site and 2.41 μg/m3at the industrial site, respectively. In addition, Pb showed the highest enrichment factors at both sites, suggesting the emissions from anthropogenic activities existed around the city. Correlation coefcient analysis and principal component analysis revealed that Cu, Fe, Mn, Pb, and Zn were originated from vehicular trafc and industrial emissions at both sites; As, Cr, and part of Pb from coal-fired power plant; Ba and Ti from natural soil. Based on the transmission electron microscopy analysis, we found that most of the trace metals were internally mixed with secondary sulfate/organic particles. These internally mixed trace metals in the urban air may have diferent toxic abilities compared with externally mixed trace metals.     

Spatial and temporal patterns in summertime sulfate aerosol acidity and neutralization within a metropolitan area

A study of sulfate aerosol acidity in Metropolitan Toronto was conducted during the summer of 1986. Fine-fraction aerosol (<2.5-μm) were collected using Teflon membrane filters and analyzed for major ionic species (H⁺, NH⁺₄, NO⁻₃, SO²⁻₄). Samples were collected for 6 weeks at three study sites: one in the Center City and the others 13 km (WNW) and 20 km (NE) away. There were very strong correlations among the three sites with respect to measured aerosol species (r² > 0.9 for 24-h data). However, spatial variations in the magnitude of aerosol acidity were observed during sulfate episodes. For example, the peak concentrations for all sites occurred on 25–26 July 1986. While the 24-h data for sulfate were quite uniform at the three sites (34, 34 and 35 μg m⁻³), H⁺ concentrations were 9.4, 8.3 and 6.0 μg m⁻³ (as H₂SO₄) for the NE, WNW and Center City sites, respectively. For most of the summertime episodes, the downtown area also had lower aerosol acidity compared to the two sites in suburban areas.     

Transported acid aerosols measured in southern Ontario

During the period 29 June 1986–9 August 1986, a field health study assessing the acute health effects of air pollutants on children was conducted at a summer girls' camp on the northern shore of Lake Erie in SW Ontario. Continuous air pollution measurements of SO₂, O₃, NO_x, particulate sulfates, light scattering, and meteorological measurements including temperature, dew point, and wind speed and direction were made. Twelve-hour integrated samples of size fractioned particles were also obtained using dichotomous samplers and Harvard impactors equipped with an ammonia denuder for subsequent hydrogen ion determination. Particulate samples were analyzed for trace elements by X-ray fluorescence and Neutron Activation, and for organic and elemental carbon by a thermal/optical technique. The measured aerosol was periodically very acidic with observed 12-h averaged H⁺ concentrations in the range < 10–560 nmoles m⁻³. The aerosol H⁺ appeared to represent the net strong acidity after H₂SO₄ reaction with NH₃(g). Average daytime concentrations were higher than night-time for aerosol H⁺, sulfate, fine mass and ozone. Prolonged episodes of atmospheric acidity, sulfate, and ozone were associated with air masses arriving at the measurement site from the west and from the southwest over Lake Erie. Sulfate concentrations measured at the lakeshore camp were more than twice those measured at inland sites during extreme pollution episodes. The concentration gradient observed with onshore flow was potentially due to enhanced deposition near the lakeshore caused by discontinuities in the meteorological fields in this region.     

Online monitoring of water-soluble ionic composition of PM10 during early summer over Lanzhou City

Lanzhou is one of the most aerosol-polluted cities in China. In this study, an online analyzer for Monitoring for AeRosols and GAses was deployed to measure major water-soluble inorganic ions in PM10 at 1-hour time resolution, and 923 samples were obtained from Apr 1 to May 24, 2011. During the field campaign, air pollution days were encountered with Air Quality Index more than 100 and daily average concentration of PM10 exceeding 150 μg/m3. Based on the variation of water-soluble ions and results of Positive Matrix Factorization 3.0 model execution, the air pollution days were classified as crustal species- or secondary aerosol-induced, and the different formation mechanisms of these two air pollution types were studied. During the crustal species pollution days, the content of Ca2+increased and was about 2.3 times higher than the average on clear days, and the air parcel back trajectory was used to analyze the sources of crustal species. Data on sulfate, trace gases and meteorological factors were used to reveal the formation mechanism of secondary aerosol pollution. The sulfur oxidation ratio(SOR) was derived from the 923 samples, and the SOR had high positive correlation with relative humidity in early summer in Lanzhou.     

Fogwater chemistry at Riverside,California

Fog, aerosol, and gas samples were collected during the winter of 1986 at Riverside, California. The dominant components of the aerosol were NH₄⁺, NO₃⁻, and SO₄₂₋. Gaseous NH₃ was frequently present at levels equal to or exceeding the aerosol NH₄⁺. Maximum level were 3800, 3100, 690 and 4540 neq m⁻³ for NH₄⁺, NO₃²⁻ and NH_3(g), respectively. The fogwater collected at Riverside had very high concentrations, particularly of the major aerosol components. Maximum concentrations were 26,000 29,000 and 6200 μM for NH₄⁺, NO₃⁻ and SO₄²⁻, respectively. pH values in fogwater ranged from 2.3 to 5.7. Formate and acetate concentrations as high as 1500 and 580 μM, respectively, were measured. The maximum CH₂O concentration was 380 μM. Glyoxal and methylglyoxal were found in all the samples; their maximum concentrations were 280 and 120 μM, respectively. Comparison of fogwater and aerosol concentrations indicates that scavenging of precursor aerosol by fog droplets under the conditions at Riverside is less than 100% efficient.The chemistry at Riverside is controlled by the balance between HNO₃ production from NO_x emitted throughout the Los Angeles basin and NH₃ emitted from dairy cattle feedlots just west of Riverside. The balance is controlled by local mixing. Acid fogs result at Riverside when drainage flows from the surrounding mountains isolate the site from the NH₃ source. Continued formation of HNO_3(g) in this air mass eventually depletes the residual NH_3(g). A simple box model that includes deposition, fog scavenging, and dilution is used to assess the effect of curtailing the dairy cattle feedlot operations. The calculations suggest that the resulting reduction of NH₃ levels would decrease the total NO₃⁻ in the atmosphere, but nearly all remaining NO₃⁻ would exist as HNO₃. Fogwater in the basin would be uniformly acidic.     

Benzene, toluene and xylenes levels in new and used vehicles of the same model

The aim of this work was to determine the level of benzene, toluene, o-xylene and m, p-xylene （BTX） in air samples collected from the cabins of new and used vehicles of the same model. Ten new vehicles were examined in order to check interior emission from materials used to equip the passenger compartment. In order to compare and define the impact of exhaust gases, air samples were also collected from two used cars, at different mileages （up to 20,000 kin）. All vehicles tested were of the same type. Samples were collected onto Carbograph 1TD sorbent, thermally desorbed and examined with the use of gas chromatography with flame ionisation and mass spectrometry detectors. All results obtained were referred to Polish and German requirements for indoor air quality （both in public buildings and in workspace environments）. Average benzene, toluene, o-xylene and m, p-xylene concentrations in new cars were determined at the level of 11.8 μg/m^3, 82.7 μg/m^3, 21.2 μg/m^3 and 89.5 μg/m^3, respectively. In the used cars, BTX concentration increased with increasing vehicle mileage. The most significant increase of BTX concentration was observed above 11,000 km mileage.     

Spatial and temporal variation of particulate matter and gaseous pollutants in 26 cities in China

O3and PM2.5were introduced into the newly revised air quality standard system in February 2012, representing a milestone in the history of air pollution control, and China's urban air quality will be evaluated using six factors(SO2, NO2, O3, CO, PM2.5and PM10) from the beginning of 2013. To achieve the new air quality standard, it is extremely important to have a primary understanding of the current pollution status in various cities. The spatial and temporal variations of the air pollutants were investigated in 26 pilot cities in China from August 2011 to February 2012, just before the new standard was executed. Hourly averaged SO2, NO2and PM10were observed in 26 cities, and the pollutants O3, CO and PM2.5were measured in 15 of the 26 cities. The concentrations of SO2and CO were much higher in the cities in north China than those in the south. As for O3and NO2, however, there was no significant diference between northern and southern cities. Fine particles were found to account for a large proportion of airborne particles, with the ratio of PM2.5to PM10ranging from 55% to 77%. The concentrations of PM2.5(57.5 μg/m3) and PM10(91.2 μg/m3) were much higher than the values(PM2.5: 11.2 μg/m3; PM10 : 35.6 μg/m3) recommended by the World Health Organization. The attainment of the new urban air quality standard in the investigated cities is decreased by 20% in comparison with the older standard without considering O3, CO and PM2.5, suggesting a great challenge in urban air quality improvement, and more eforts will to be taken to control air pollution in China.