Cairo Atmosphere Research Articles

Impact of air pollutants on some building materials in Cairo atmosphere

Impact of air pollutants on some building materials in Cairo atmosphere

Radioactive contamination of the atmosphere of Cairo, Egypt, from the Fukushima Dai-ichi nuclear plant accident

Radioactive contamination in air dust particles of Cairo atmosphere from the Fukushima accident was detected by the gamma-ray spectroscopy technique. Analysis of the spectra obtained by using an High-Purity Germanium detector showed that there were some traces of 131I and 134, 137Cs. Estimate and study of concentration of those radionuclides were done over a period of about 5 months after the accident. Comparison with corresponding results in different countries all over the world has been performed.

Weekday/weekend differences in ambient aerosol level and chemical characteristics of water-soluble components in the city centre

Weekday and weekend ambient aerosol samples were collected from the city centre of Cairo, namely “Ramsis” during the summer season of the year 2006, and have been analyzed for water-soluble ionic species. The average concentrations of the total suspended particulate matter (TSP) and their water-soluble components were higher during weekdays than on weekends, indicating that the decreased traffic density on weekends leads to a decrease in the levels of the TSP and their water-soluble ionic species. The average concentrations of the TSP were 454 μg m −3 on weekdays and 298 μg m −3 on weekends. The weekday/weekend concentration ratios were 1.52 for TSP, 1.27 for SO 4 2−, 1.64 for Cl −, 1.54 for NO 3 −, 1.17 for NH 4 +, 1.67 for Ca 2+, 1.83 for Na +, 1.75 for K + and 1.73 for Mg 2+. City centre of Cairo has high levels of the TSP and their water-soluble ionic species compared with many polluted cities in the world. Among all of the measured water-soluble components, SO 4 2− was the most abundant species followed by Ca 2+ on weekdays and weekends. The average mass ratios of NO 3 −/SO 4 2− in the TSP were 0.41 on weekdays and 0.34 on weekends, suggesting that the stationary source emissions were more predominant. The NH 4 +/SO 4 2− molar ratios and its relation with the concentrations of TSP and Ca 2+ during the weekdays and weekends indicate that the chemical form of sulfate and ammonium in aerosol particles varies with TSP and Ca 2+ levels. At high TSP and Ca 2+ levels, and NH 4 +/SO 4 2− molar ratios less than one, SO 4 2− in aerosol particles may be present as CaSO 4 and (NH 4) 2SO 4·CaSO 4·2H 2O, whereas it is expected to be present as (NH 4) 2SO 4, (NH 4) 2SO 4·CaSO 4·2H 2O and CaSO 4 at low levels of TSP and Ca 2+, and NH 4 +/SO 4 2− molar ratios between 1 and 2. The mean pH values of the TSP were 7.65 on weekdays and 6.97 on weekends, indicating that aerosol particles brought a large amount of crustal species, and might alleviate the tendency of acidification. The relationships between the concentrations of acidic components (NO 3 − and SO 4 2−) and basic components (NH 4 +, Ca 2+ and Mg 2+) on weekdays and weekends indicate that the acidity of aerosol particles is neutralized. Ca 2+ and NH 4 + are the most dominant neutralization substances in Cairo atmosphere.

Sensitivity of ultraviolet solar radiation to anthropogenic air pollutants and weather conditions

The main objective of this study is to shed light on the influence of air pollutants on the ultraviolet (UV) radiation reaching the earth surface. A short discussion of the role played by weather conditions in determining the levels of the UV radiation is also given. The atmosphere of Cairo was chosen for the polluted case. On the other hand, Aswan and El-Kharga were chosen for the clarity of the atmosphere. To ensure that the fraction of the seasonal variability induced by the variation of the solar zenith angle (SZA) is removed from the UV time series, all data were separated into subsets of data corresponding to the selected SZA. According to the results obtained, the annual value of the UV radiation tends to decrease as the year pass. This is partly because air pollutants, can reduce the increased levels of UV radiation by 39.6% (relative to background value), and explains why the expected UV increases have not been observed.

Source Profiles for Nonmethane Organic Compounds in the Atmosphere of Cairo, Egypt

ABSTRACT Profiles of the sources of nonmethane organic compounds (NMOCs) were developed for emissions from vehicles, petroleum fuels (gasoline, liquefied petroleum gas [LPG], and natural gas), a petroleum refinery, a smelter, and a cast iron factory in Cairo, Egypt. More than 100 hydrocarbons and oxygenated hydrocarbons were tentatively identified and quantified. Gasoline-vapor and whole-gasoline profiles could be distinguished from the other profiles by high concentrations of the C5 and C6 saturated hydrocarbons. The vehicle emission profile was similar to the whole-gasoline profile, with the exception of the unsaturated and aromatic hydrocarbons, which were present at higher concentrations in the vehicle emission profile. High levels of the C2-C4 saturated hydrocarbons, particularly n-butane, were characteristic features of the petroleum refinery emissions. The smelter and cast iron factory emissions were similar to the refinery emissions; however, the levels of benzene and toluene were greater in the former two sources. The LPG and natural gas emissions contained high concentrations of n-butane and ethane, respectively. The NMOC source profiles for Cairo were distinctly different from profiles for U.S. sources, indicating that NMOC source profiles are sensitive to the particular composition of petroleum fuels that are used in a location.

AirborneAlternariaSpores: Potential Allergic Sensitizers in Saudi Arabia

In order to investigate the role of airborne Alternaria spp. in the sensitization of individuals having respiratory allergy symptoms, particularly bronchial asthma, an aerobiologic and clinical (diagnostic) study was conducted at several centers in Saudi Arabia. Airborne Alternaria spores were studied at four different centers in Riyadh, Jeddah and Al-Khobar, including three years at one site. Skin prick tests (SPT) were conducted on a total of 616 allergic individuals attending allergy clinics at six different hospitals in Abha, Qassim, Gizan, Jeddah, Hofuf and Makkah regions. Alternaria spores constituted between 1.9%-9.6% of the total fungal air spora, and the maximum concentration exceeded 5x10 2 spores per m3 of air in Jeddah, followed by 4.9x102 spores per m3 in Al-Khobar. Mean weekly and monthly concentration of Alternaria fluctuated, reaching up to 150 spores per m 3 and 60 spores per m 3, respectively. Quantitative regional variations were also recorded. IgE-mediated SPT reactivities conducted on allergic patients resulted in an overall 21.6% positive reactions, showing mild, moderate and strong wheal and erythema. The findings reveal that Alternaria spores are prevalent as a major component in the outdoor environment of the Kingdom, with peaks in April and October. The overall 21.6% positive SPT reactions indicate the sensitization level or cross-reactive sensitivity to Alternaria allergens. The study suggests that airborne Alternaria can be a potential allergic sensitizer in susceptible individuals and can be a risk factor in sensitized individuals with symptoms of bronchial asthma and allergic rhinitis in the Kingdom of Saudi Arabia.

Silicon, aluminium, iron, copper and zinc levels in desert soil-related dust deposits in Cairo

Silicon, aluminium, iron, copper and zinc were measured in dust deposits in one of the residential areas close to desert and semi-desert regions in Cairo. The five metals were also determined in samples taken from the desert soil. All analyses were undertaken in the different size portions of the collected samples. It could be shown that Si, Al and Fe have a major contribution either in dust deposits or in desert soil, whereas Cu and Zn have a minor contribution. Besides, the five metals exhibit a consistent increase in their concentrations with decreasing particle size. Through the use of calculated enrichment factors, it could be suggested that the dust originating from desert and semi-desert areas has a strong role in polluting the Cairo atmosphere with Si, Al, Fe and Cu and to a lesser degree with Zn. However, it was found that the Si Al ratio in dustfall is less than that in desert soil. This could be attributed to the contribution of the alluvial soil of the Nile to dust deposition over the city.

Airborne Spores of Opportunistic Fungi in the Atmosphere of Cairo, Egypt

Abstract The prevalence of yeast spores in the atmosphere of Cairo as determined by the Andersen air sampler, was investigated at four sites over a period of one year. The average total count showed seasonal periodicity. The maximum count was recorded in autumn and the minimum in summer. Eighteen species of yeasts belonging to 9 genera were recovered and identified. The opportunistic genera of yeasts represented by seven genera showed high percentage of the total count. The most prevalent genera Cryptococcus, Candida and Rhodotorula constituting, 26.6%, 19.9% and 17.9% respectively. Other genera of low count were Kluyveromyces (7.4%). Debaryomyces (4.3%) and Trichosporon (3.2%).

Prevalence of Opportunistic Thermophilic Actinomycetes in the Atmosphere of Cairo, Egypt

Abstract Thermophilic Actinomycetes were isolated by means of Andersen Sampler from four sampling sites. The total count recorded was relatively low. Four different opportunistic species were isolated in this study, Saccharomonospora viridis (syn. Thermomonospora viridis) 17%, Thermoactinomyces vulgaris (syn. T. candidus) 16.2%, Micropolyspora faeni 6.7% and Thermoactinomyces sacchari 5.2%.

Airborne spores of opportunistic fungi in the atmosphere of cairo, egypt

Abstract The prevalence of airborne mould spores at four sites in Cairo was determined using an Andersen air sampler over a period of one year. The average total count varied seasonally and maxima were recorded in winter at all sampling sites. One hundred and fifteen species of moulds belonging to forty‐two genera were isolated. Cladosporium was isolated more frequently (39.6%) than Aspergillus (27.2%), Penicillium (14.1%), Cumularia (4%), Neurospora (3.2%) and Alternaria (2.5%). Opportunistic moulds of clinical significance represented 22 genera and constituted 75 to 100% of the total mould count.

Spatial and seasonal variation of lead in Cairo atmosphere

Spatial and seasonal variation of lead concentrations were investigated in the Cairo atmosphere. It was found that the annual mean lead concentrations in the central and densely populated parts of Cairo exceeded the 2μm −3 recommended limit. In sharp contrast to data for European cities, summer lead concentrations were higher than those detected during winter. Calculated settling velocities of lead particles show that in the central urban district lead particles can stay suspended for long periods, and so are available for inhalation, as compared with particles found in the atmosphere of other parts of the city.

Particulate matter in the Cairo atmosphere. 1. Dustfall and its chemical constituents

Dustfall, sampled in different parts of Cairo, has been analysed for selected constituents in soluble and insoluble fractions. We show that the rate of total particulate deposition over Cairo increased from 27 g/m 2 · 30 days during 1962 to 57 g/m 2 · 30 days in 1983; the highest rates of deposition were recorded during winter and spring months, while the maximum concentrations of soluble compounds were found during the summer season. The high concentrations of ammonium and sulphates detected in dustfall over Cairo during summer indicates that atmospheric chemical reactions play an important role in this increase of soluble compounds concentration. The rate of deposition in different districts and the chemical composition indicate that particulate matter in Cairo atmosphere is influenced by urban activities and winds loaded with dust from the industrial areas north and south of the city. Furthermore, i.r. spectroscopic analysis show absorption bands at about 2950, 2920, 2820, 2720, 1720, 1465, 1385, 1300 and 1100 cm −1 which are characteristic bands for aliphatic hydrocarbons, aldehydes, and ketones. The presence of these compounds and the high concentration of tarry matter confirm the role of combustion processes in polluting the atmosphere of Cairo.

Water vapor in polluted Cairo atmosphere

Hourly measurements for each of the five solar bands selected by the filters of the Volz multichannel sunphotometer together with ambient air temperature and relative humidity are carried out. Figures and tables are given to show variation of precipitable water, relative, humidity, vapor pressure, ambient air temperature, and turbidity. An empirical relation is obtained to show the variation of vapor pressure at ground surface with precipitable water layer through the atmosphere of Cairo.

Effect of pollutant aerosols on spectral atmospheric transmissivity in Cairo

Spectral atmospheric transmissivity has been greatly affected by air pollutants in Cairo atmosphere. This has been studied by measuring the energy of solar radiation, selecting four bands at different wave-lenghts. Three selected bands are in the visible (blue 440 nm., green 500 nm., and red 640 nm.), while the fourth band is in the infrared region (880 nm.). The Cairo atmosphere was found to be greatly polluted by fine particulates, which were held in suspension for a longer time than coarse pollutants. The transmissivity of the spectral radiation showed a clear wavelength dependence comparable to particulate sizes found in different concentrations. The transmissivity was found to be highest for the infrared band, followed by the red and then the green bands, and the lowest was for the blue band.

Characteristics of storm deposited dust at Cairo

Samples of deposited dust during stormy weather conditions passing Cairo have been analysed chemically and microscopically. Carbonate, clay and quartz content of both deposited dust and soil samples taken from three localities around the city identified the contribution of the surrounding deserts, Mokattam hills and Nile Valley in polluting the Cairo atmosphere with wind-blown soils during storms. Disregarding dust particles having diameters > 60 μm, the size distribution of all samples fitted a lognormal distribution. Further, the number median diameters were found to be between 2.8 and 8.5 μm. Highly significant correlation between mean wind speed prevailing during storms and median diameters of dust particles reveals the role of strong winds for carrying comparatively large sized dust particles.

Smoke concentration in the greater Cairo atmosphere

A study of smoke content of the atmosphere over the Greater Cairo area was conducted during the 12 months from June 1977 to May 1978. Smoke samples were taken continuously over two-hour periods at two sites, one in Shubra El-Kheima industrial sector on the northern boundary of the study area and the other in a purely residential district about 15 km south-south-west of the first site. A comparison was made between the averaged concentrations at both sites. It was found that the industrial area was considerably higher in smoke contamination and that industrial activity is the principal source of smoke in the Cairo atmosphere. Daily and yearly cycles of smoke concentration were also studied and discussed in terms of man-made source activities and meteorological conditions. Concentrations were found to be much higher in the cold months. The daily cycle rhythm was the same at the two sites, having two well developed maxima in the morning and late evening and a pronounced minimum in the mid-afternoon. Daily maxima were almost of the same order of magnitude in each site. The morning maximum seemed to be formed by fumigation just after sunrise in the industrial sector and appeared two hours later in the downwind residential district. No significant difference was found between smoke concentrations during weekdays and weekends.