Applications of redundancy analysis for the detection of chemical response patterns to air pollution in lichen

The lichens Ramalina celastri (Spreng.) Krog & Swinsc., Punctelia microsticta (Müll. Arg.) Krog and Canomaculina pilosa (Stizenb.) Elix & Hale were transplanted simultaneously to 17 urban-industrial sites in a northwestern area of Córdoba city, Argentina. The transplantation sites were set according to different environmental conditions: traffic, industries, tree cover, building height, topographic level, position in the block and distances from the river and from the power plant. Three months later, chlorophyll a, chlorophyll b, phaeophytin a, soluble proteins, hydroperoxy conjugated dienes, malondialdehyde concentration and sulfur accumulation were determined, and a pollution index was calculated for each sampling site. Redundancy analysis was applied to detect the variation pattern of the lichen variables that can be 'best' explained by the environmental variables considered. The present study provides information about both the specific pattern response of each species to atmospheric pollution, and environmental conditions that determine it. As regards pollutants emission sources R. celastri showed a chemical response associated mainly with pollutant released by the power plant and traffic. P. microsticta and C. pilosa responded mainly to industrial sources. Regarding environmental conditions that affect the spreading of air pollutants and their incidence on the bioindicator, the topographic level and tree cover surrounding the sampling site were found to be important for R. celastri, tree cover surrounding the sampling site and the building height affected P. microsticta, while building height did so for C. pilosa.

Degradation of VOCs by phototcatalytic oxidation reactor using TiO2 pellets

Volatile Organic Compounds (VOCs) are air pollutants that come from burning fossil fuels and industrial emissions. They have potentially adverse health effects being carcinogenic and highly persistent in the environment. The use of photocatalytic oxidation to remove VOCs has the potential to be applied in indoor air quality improvement and industrial emission control. A fixed bed photocatalytic reactor was designed and built. UV black light lamps were installed in the reactor to provide a source of UV radiation. A non-film titania media as pellets were placed on the three fixed beds within the reactor. Toluene and acetone were used as indicators of VOCs during the experiment. With a flow rate of 12.75l/min, the oxidation efficiencies were obtained at four different concentrations of acetone laden gas streams ranging from 40ppm to 250ppm. It was found that the lower the acetone concentration of the untreated inlet gas, the higher the oxidation efficiency. The oxidation efficiency was in the range of 40–70% for various concentrations of untreated gases. Two concentrations of toluene laden gas stream were also tested using the same reactor. The oxidation efficiencies were found as 50% for 120ppm toluene gas and 45% for 300ppm toluene gas. It was found that the times required for toluene to reach oxidization equilibrium have been halved than for acetone gas stream. Other parameters such as flow rate and UV intensity were also altered to see their effects on the oxidation efficiency. A full spectrum scan was carried out using a Bio-rad Infrared spectrometer. It was found that the main components of the treated gas stream from the outlet of the reactor were CO2 and water along with small amount of untreated acetone. The suspected intermediates of aliphatic hydrocarbons and CO were found in very minimal amounts or undetectable. The research experiments supported that the TiO2 pellets can work effectively in a fixed bed photocatalytic reactor and achieve significant oxidation efficiencies for degradation of toluene and acetone as indicators of VOCs.

Atmospheric quality and distribution of heavy metals in Argentina employing Tillandsia capillaris as a biomonitor.

The atmospheric quality and distribution of heavy metals were evaluated throughout a wide region of Argentina. In addition, the biomonitor performance of Tillandsia capillaris Ruiz & Pav. f. capillaris was studied in relation to the accumulation of heavy metals and to its physiologic response to air pollutants. A sampling area of 50,000 km2 was selected in the central region of the Argentine Republic. This area was subdivided into grids of 25 x 25 km. Pools of T. capillaris, where present, were collected at each intersection point. From each pool three sub-samples were analyzed independently. Furthermore, five replicates were collected at 20% of the points in order to analyze the variability within the site. The content of Co, Cu, Fe, Ni, Mn, Pb and Zn was determined by Atomic Absorption Spectrometry. Chemical-physiological parameters were also determined to detect symptoms of foliar damage. Chlorophylls, phaeophytins, hydroperoxy conjugated dienes, malondialdehyde and sulfur were quantified in T. capillaris. Some of these parameters were used to calculate a foliar damage index. Data sets were evaluated by one-way ANOVA, correlation analysis, principal component analysis and mapping. Geographical distribution patterns were obtained for the different metals reflecting the contribution of natural and anthropogenic emission sources. According to our results it can be inferred that Fe, Mn and Co probably originated in the soil. For Pb, the highest values were found in the mountainous area, which can be attributed to the presence of Pb in the granitic rocks. Ni showed mainly an anthropogenic origin, with higher values found in places next to industrial centers. For Zn the highest values were in areas of agricultural development. The same was observed for Cu, whose presence could be related to the employment of pesticides. The foliar damage index distribution map showed that the central and southeastern zones were the ones where the major damage in the bioindicator was found. The central zone coincides with the city of Córdoba whereas the southeastern area is strictly agricultural, so the high values found there could be related to the use of pesticides.

Outdoor fungi and child asthma health service attendances

Asthma is a significant global public health issue. Severe asthma exacerbations can be triggered by environmental factors and require medical care from health services. Although it is known that fungal exposure may lead to allergic sensitization, little is understood about its impact on asthma exacerbations. This review aims to examine whether outdoor fungi play a significant role in child asthma exacerbations. Systematic search of seven electronic databases and hand searching for peer-reviewed studies published in English, up to 31 August 2013. Inclusion criteria were study population aged <18 yr, diagnosis of asthma, attended a health service; outdoor fungi exposure was reported. Quality and risk of bias assessments were conducted. Due to significant heterogeneity, meta-analysis was not conducted. Of the 1896 articles found, 15 were eligible. Findings were not consistent, possibly due to methodological variations in exposure classifications, statistical methods and inclusion of confounders. Cross-sectional studies found no or weak associations. All but one time series studies indicated an association that varied between fungal species. Increasing evidence indicates that asthmatic children are susceptible to asthma exacerbations when exposed to outdoor fungal spores. There is limited understanding of the contributions of different fungal species. Research is needed to investigate interactions of outdoor fungi with pollen, air pollutants and respiratory viruses.

Associations between outdoor fungal spores and childhood and adolescent asthma hospitalisations.

BACKGROUND: Childhood asthma is a significant public health problem and severe exacerbations can result in diminished quality of life and hospitalisation. OBJECTIVE: To examine the contribution of outdoor fungi to childhood and adolescent asthma hospitalisations. METHODS: The Melbourne Air Pollen Children and Adolescent (MAPCAH) study is a case-crossover study of 644 children and adolescents (aged 2-17 years) hospitalised for asthma. MAPCAH collected individual data on human rhinovirus (HRV) infection and sensitisation to Alternaria and Cladosporium; and daily counts of ambient concentrations of fungal spores, pollen and air pollutants. Conditional logistic regression models were used to assess associations with increases in spore counts while controlling for potential confounding and testing interactions. RESULTS: Exposure to Alternaria (aOR=1.07, 95%CI 1.03-1.11), Leptosphaeria (aOR=1.05, 95%CI 1.02-1.07), Coprinus (aOR=1.04, 95%CI 1.01-1.07), Drechslera (aOR=1.03, 95%CI1.00-1.05) and total spores (aOR=1.05, 95%CI 1.01-1.09) were significantly associated with child asthma hospitalisations independent of HRV infection. There were significant lagged effects up to 3-days with Alternaria, Leptosphaeria, Cladosporium, Sporormiella, Coprinus, and Drechslera. Some of these associations were significantly greater in participants with Cladosporium sensitisation. CONCLUSION: Exposures to several outdoor fungal spore taxa, including some not reported in previous research, are associated with the risk of child and adolescent asthma hospitalisation, particularly in individuals sensitised to Cladosporium. We need further studies to examine cross-reactivity causing asthma exacerbations. Identifying sensitisation to multiple fungal allergens in asthmatic children could support the design and implementation of more effective strategies to prevent asthma exacerbations.

High-resolution monitoring of atmospheric pollutants using a system of low-cost sensors

Increased levels of particulate matter (PM) in the atmosphere have contributed to an increase in mortality and morbidity in communities and are the main contributing factor for respiratory health problems in the population. Currently, PM concentrations are sparsely monitored; for instance, a region of over 2200 square kilometers surrounding Melbourne in Victoria, Australia, is monitored using ten sensor stations. This paper proposes to improve the estimation of PM concentration by complementing the existing high-precision but expensive PM devices with low-cost lower precision PM sensor nodes. Our evaluation reveals that local PM estimation accuracies improve with higher densities of low-precision sensor nodes. Our analysis examines the impact of the precision of the lost-cost sensors on the overall estimation accuracy.