Our knowledge of the concentrations of bioaerosols in residential micro-environments in low income countries is scanty. The present investigation was conducted to assess the culturable concentration and size distribution of bacteria, gram negative bacteria and fungi in two rural and an urban site in Pakistan. The highest indoor culturable bacteria concentration was found at Rural Site II (14,650 CFU/m³) while the outdoor maximum occurred at the urban site (16,416 CFU/m³). With reference to fungi, both indoor and outdoor concentrations were considerably higher at Rural Site I than the other sites. The size distribution of culturable bacteria at all sites showed greater variability than that of culturable fungi. At all sites more than the half (55–93%) of the culturable bacterial and fungal counts were observed in the respirable fraction (<4.7 μm) and so had the potential to penetrate into lower respiratory system.

Levoglucosan was present in all samples and its concentrations showed a pronounced annual cycle with maximum levels in the cold season. The annual percentage of ratios of levoglucosan to OC ranged from 0.04 to 9.75% evidencing a major contribution of biomass burning to the aerosol OC during the winter. In the urban-background site, OC was strongly correlated with EC in winter, suggesting that the major fraction of OC was generated as primary particles along with EC. A background levoglucosan component showed that biomass burning was continuously taking place in all the investigated sites. The biomass burning contribution to the Tuscany aerosol was made up of a background component and an additional component during winter probably due to wood burning for domestic heating.

This work presents a diagnostic methodology in support to source apportionment studies to identify remote and local pollution sources. It is based on the temporal analysis of both PM size distributions and PM size fraction correlation along with natural radioactivity measurements as index of Planetary Boundary Layer dynamic. A correlation drop is indicative of changing aerosol sources. When this observation is coupled with decreasing level of natural radioactivity and increasing aerosol concentration, be it coarse or fine, it is indicative of the inflow of remote polluted air masses. The methodology defines in which size range operates the contribution of remote pollution sources. It was applied to two PM10 pollution episodes: the first involved the advection of coarse PM, the second entailed the inflow of two air masses, one transporting coarse dust and the other fine PM. Dust models and backward trajectories analysis confirmed such results, indicating the air mass provenience.

In recent years the pollution of indoor air with ultrafine particles has been an object of intensive research. Several studies have concurred in demonstrating that outdoor air makes only a limited contribution to polluting indoor air with ultrafine particles, provided significant sources in the immediate neighborhood are absent. Nowadays, electrical devices operated in homes and offices are identified as particle emission sources. A comparison of the emission rates can be made by calculating the total number of particles released with respect to the operating time. The identified particles are condensed semi-volatile organic compounds with a low percentage of non-volatile inorganic components. To characterize the indoor exposure to airborne particles, an algorithm has been developed which permits a realistic calculation of the particle intake and deposition in the human respiratory tract from measured size and time resolved particle number concentrations following the model of the International Commission on Radiological Protection.

Polycyclic aromatic hydrocarbon (PAH) extracts of fine particles (PM₂.₅) collected from combustion of seven wood species and briquettes were tested for mutagenic activities using Ames test with Salmonella typhimurium TA98 and TA100. The woods were Pinus pinaster (maritime pine), Eucalyptus globulus (eucalypt), Quercus suber (cork oak), Acacia longifolia (golden wattle), Quercus faginea (Portuguese oak), Olea europea (olive), and Quercus ilex rotundifolia (Holm oak). Burning experiments were done using woodstove and fireplace, hot start and cold start conditions. A mutagenic response was recorded for all species except golden wattle, maritime pine, and briquettes. The mutagenic extracts were not correlated with high emission factors of carcinogenic PAHs. These extracts were obtained both from two burning appliances and start-up conditions. However, fireplace seemed to favour the occurrence of mutagenic emissions. The negative result recorded for golden wattle was interesting, in an ecological point of view, since after confirmation, this invasive species, can be recommended for domestic use.

After the accident in Fukushima reactors, a daily monitoring programme was initiated in two laboratories in Belgrade, one at the Vinčа Institute for Nuclear Sciences and the other at Institute for Occupational Health Karajovic. Samples of aerosol and fallout, as well as the random samples of food and water, were collected and analysed, using gross alpha/beta and gamma spectrometry, in order to establish the presence of traces of isotopes indicating Fukushima fallout. Gamma spectrometry measurement of these samples showed clear evidence of fission products ¹³¹I, ¹³⁴Cs and ¹³⁷Cs wtihin 2 weeks after the accident. The activity diminished with time due to dispersion in air and, in case of ¹³¹I, short half-life.

To elucidate the influence of airborne materials on the ecosystem of Japan’s Yakushima Island, we determined the elemental compositions and Sr and Nd isotope ratios in streamwater, soils, vegetation, and rocks. Streamwater had high Na and Cl contents, low Ca and HCO₃ contents, and Na/Cl and Mg/Cl ratios close to those of seawater, but it had low pH (5.4 to 7.1), a higher Ca/Cl ratio than seawater, and distinct ⁸⁷Sr/⁸⁶Sr ratios that depended on the bedrock type. The proportions of rain-derived cations in streamwater, estimated by assuming that Cl was derived from sea salt aerosols, averaged 81 % for Na, 83 % for Mg, 36 % for K, 32 % for Ca, and 33 % for Sr. The Sr value was comparable to the 28 % estimated by comparing Sr isotope ratios between rain and granite bedrock. The soils are depleted in Ca, Na, P, and Sr compared with the parent materials. At Yotsuse in the northwestern side, plants and the soil pool have ⁸⁷Sr/⁸⁶Sr ratios similar to that of rainwater with a high sea salt component. In contrast, the Sr and Nd isotope ratios of soil minerals in the A and B horizons approach those of silicate minerals in northern China’s loess soils. The soil Ca and P depletion results largely from chemical weathering of plagioclase and of small amounts of apatite and calcite in granitic rocks. This suggests that Yakushima’s ecosystem is affected by large amounts of acidic precipitation with a high sea salt component, which leaches Ca and its proxy (Sr) from bedrock into streams, and by Asian dust-derived apatite, which is an important source of P in base cation-depleted soils.

Perchlorate (ClO 4 − ), a thyroid hormone disruptor, is both naturally occurring and a man-made contaminant increasingly found in a variety of terrestrial environments. The environmental presence of ClO 4 − is considered to be the result of atmospheric formation and deposition processes. The ultimate processes, particularly heterogeneous-based reactions, leading to natural ClO 4 − formation are not well understood. Oxidation of chlorine species by an energetic source such as lightning is considered to be one of the potential heterogeneous sources of natural ClO 4 − . Currently, there is very little information available on lightning-induced ClO 4 − . We designed a laboratory electrical discharge reactor capable of evaluating ClO 4 − formation by the oxidation of “dry” sodium chloride (NaCl) aerosols (relative humidity (RH) <70%) in electrical discharge plasma at voltages and energies up to 24 kV and 21 kJ, respectively. Similar to other non-electrochemical ClO 4 − production processes, the amount of ClO 4 − produced (0.5–4.8 μg) was 3 orders of magnitude lower than the input Cl− (7.1–60.1 mg). The amount of ClO 4 − generated increased with peak voltage (V) and theoretical maximum discharge energy with ΔClO 4 − /ΔV = 0.28 × 10−3 μg V−1 (R 2 = 0.94) and ΔClO 4 − /ΔE = 0.44 × 10−3 μg J−1 (R 2 = 0.83). The total ClO 4 − generated decreased with an increase in relative humidity from 2.8 ± 0.1 μg (RH ∼46%) to 0.9 ± 0.1 μg (RH ∼62%) indicating that the presence of moisture inhibits the formation of ClO 4 − . Additional modifications to the reactor support the hypothesis of ClO 4 − formation due to the action of plasma on Cl− aerosols as opposed to direct oxidation on the surface of the electrodes. Finally, the contribution of lightning-induced ClO 4 − in North America is calculated to have a wide range from 0.006 × 105 to 5 × 105 kg/year and is within the range of the measured ClO 4 − depositional flux in precipitation samples obtained across the USA (0.09 × 105–1.2 × 105 kg/y).

BACKGROUND: PM10 aerosol samples were simultaneously collected at two urban and one urban background sites in Fuzhou city during two sampling campaigns in summer and winter. PM10 mass concentrations and chemical compositions were determined. METHODS: Water-soluble inorganic ions (Cl−, NO 3 − , SO 4 2− , NH 4 + , K+, Na+, Ca2+, and Mg2+), carbonaceous species (elemental carbon and organic carbon), and elements (Al, Si, Mg, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, and Pb) were detected using ion chromatography, thermal/optical reflectance, and proton-induced X-ray emission methods, respectively. RESULTS: PM10 mass concentrations, as well as most of the chemical components, were significantly increased from urban background to urban sites, which were due to enhanced anthropogenic activities in urban areas. Elements, carbonaceous species, and most of the ions were more uniformly distributed at different types of sites in winter, whereas secondary ion SO 4 2− , NO 3 − , and NH 4 + showed more evident urban-background contrast in this season. The chemical mass closure indicated that mineral dust, organic matters, and sulfate were the most abundant components in PM10. The sum of individually measured components accounted for 86.9–97.7% of the total measured PM10 concentration, and the discrepancy was larger in urban area than in urban background area. CONCLUSION: According to the principal component analysis–multivariate linear regression model, mineral dust, secondary inorganic ions, sea salt, and motor vehicle were mainly responsible for the PM10 particles in Fuzhou atmosphere, and contributed 19.9%, 53.3%, 21.3%, and 5.5% of PM10, respectively.

BACKGROUND: Continuous monitoring of air quality is implemented by government institutions at fixed ambient sites. However, the correlation between fixed site measurements and exposure of individual persons to air contaminants is likely to be weak. MATERIALS AND METHODS: We measured particulate matter both outdoors and indoors by following the spatial movement of individuals. Sixteen test persons took part and carried a measurement backpack for a 24-h period. The backpack was comprised of a Grimm Aerosol Spectrometer model 1.109, a GPS device, and a video camera for tracking of human behavior. The spectrometer provided information about particle numbers and mass in 32-size classes with a high temporal resolution of 6 s. RESULTS: The personal exposure of individuals during 24 h could significantly exceed the outdoor particulate matter (PM)₁₀ concentrations measured at the fixed sites. The average 24-h exposure of all test persons for PM₁₀ varied from 27 to 322 μg m⁻³. Environmental tobacco smoke and cooking emissions were among the main indoor sources for PM. The amount of particulate matter a test person was exposed to was highly dependent on the spatial behavior and the surrounding microenvironment conditions. DISCUSSION: Large-scale experiments including personal measurements might help to improve modeling approaches to approximate the actual exposure on a statistically sound basis.