Laura Duque

In vitro exposure of acer negundo pollen to atmospheric levels of SO2 and NO2: effects on allergenicity and germination

In the last years, a rising trend of pollen allergies in urban areas has been attributed to atmospheric pollution. In this work, we investigated the effects of SO(2) and NO(2) on the protein content, allergenicity, and germination rate of Acer negundo pollen. A novel environmental chamber was assembled to exposure pollen samples with SO(2) or NO(2) at two different levels: just below and two times the atmospheric hour-limit value acceptable for human health protection in Europe. Results showed that protein content was lower in SO(2)-exposed pollen samples and slightly higher in NO(2)-exposed pollen compared to the control sample. No different polypeptide profiles were revealed by SDS-PAGE between exposed and nonexposed pollen, but the immunodetection assays indicated higher IgE recognition by all sera of sensitized patients to Acer negundo pollen extracts in all exposed samples in comparison to the nonexposed samples. A decrease in the germination rate of exposed in contrast to nonexposed pollen was verified, which was more pronounced for NO(2)-exposed samples. Our results indicated that in urban areas, concentrations of SO(2) and NO(2) below the limits established for human protection can indirectly aggravate pollen allergy on predisposed individuals and affect plant reproduction.

A cost-efficiency and health benefit approach to improve urban air quality.

When ambient air quality standards established in the EU Directive 2008/50/EC are exceeded, Member States are obliged to develop and implement Air Quality Plans (AQP) to improve air quality and health. Notwithstanding the achievements in emission reductions and air quality improvement, additional efforts need to be undertaken to improve air quality in a sustainable way - i.e. through a cost-efficiency approach. This work was developed in the scope of the recently concluded MAPLIA project Moving from Air Pollution to Local Integrated Assessment, and focuses on the definition and assessment of emission abatement measures and their associated costs, air quality and health impacts and benefits by means of air quality modelling tools, health impact functions and cost-efficiency analysis. The MAPLIA system was applied to the Grande Porto urban area (Portugal), addressing PM10 and NOx as the most important pollutants in the region. Four different measures to reduce PM10 and NOx emissions were defined and characterized in terms of emissions and implementation costs, and combined into 15 emission scenarios, simulated by the TAPM air quality modelling tool. Air pollutant concentration fields were then used to estimate health benefits in terms of avoided costs (external costs), using dose-response health impact functions. Results revealed that, among the 15 scenarios analysed, the scenario including all 4 measures lead to a total net benefit of 0.3M€·y(-1). The largest net benefit is obtained for the scenario considering the conversion of 50% of open fire places into heat recovery wood stoves. Although the implementation costs of this measure are high, the benefits outweigh the costs. Research outcomes confirm that the MAPLIA system is useful for policy decision support on air quality improvement strategies, and could be applied to other urban areas where AQP need to be implemented and monitored.

Changes in the IgE-reacting protein profiles of Acer negundo, Platanus x acerifolia and Quercus robur pollen in response to ozone treatment

This study aims to investigate the effects of O3 in protein content and immunoglobulin E (IgE)-binding profiles of Acer negundo, Platanus x acerifolia and Quercus robur pollen. Pollen was exposed to O3 in an environmental chamber, at half, equal and four times the limit value for the human health protection in Europe. Pollen total soluble protein was determined with Coomassie Protein Assay Reagent, and the antigenic and allergenic properties were investigated by SDS-PAGE and immunological techniques using patients’ sera. O3 exposure affected total soluble protein content and some protein species within the SDS-PAGE protein profiles. Most of the sera revealed increased IgE reactivity to proteins of A. negundo and Q. robur pollen exposed to the pollutant compared with the non-exposed one, while the opposite was observed in P. x acerifolia pollen. So, the modifications seem to be species dependent, but do not necessarily imply that increase allergenicity would occur in atopic individuals.

Ozone effects on soluble protein content of Acer negundo, Quercus robur and Platanus spp. pollen

In this study, the effect of three different ozone (O3) levels on soluble protein content of Acer negundo, Quercus robur and Platanus spp. pollen was investigated. Pollen was directly collected from each plant and exposed to O3 values below, equal and four times the limit for human health protection in an environmental chamber system. With this chamber, it was possible to control and reproduce the O3 levels between different experiments. Total protein content was determined colorimetrically with Coomassie protein assay reagent (Pierce) by the Bradford method. Results showed that O3 has significant effects on pollen causing a decrease in soluble proteins that seem to be dependent on species and gas concentration. Also, the existence of reproducibility in the effects of O3, within the same concentration, on the protein content of pollen was verified.

Contribution of EPMA to airborne pollen analysis

As a component of aerosol, pollen is found in suspension with other mineralogical and anthropogenic particles that can adhere to the pollen wall. The aim of this study was to determine possible alterations that pollen grains suffer under different meteorological conditions in the coastal city of Porto, Portugal. For this study, 2 airborne pollen types were taken into account: Poaceae and Alnus spp sampled in July 2010 and February 2011, respectively. Quantitative analysis and X-ray map analysis were performed with a field emission electron probe microanalyzer (EPMA) equipped with 5 WDS spectrometers. Samples were mounted over adhesive carbon tape and carbon coated. Control pollen showed mainly the presence of C, O, N, P, K, Mg, S, Cl and Ca in different quantities, depending on the considered species. Airborne pollen consistently revealed a higher content of Mg and Cl than control pollen, while Si, Ca, K and P contents varied differently according to the samples. Our results show that during their flight, pollen grains acquire an external coating, become heavier and change significantly their composition.

Characterisation of particulate matter on airborne pollen grains.

A characterization of the physical-chemical composition of the atmospheric PM adsorbed to airborne pollen was performed. Airborne pollen was sampled using a Hirst-type volumetric spore sampler and observed using a Field Emission Electron Probe Microanalyser for PM analysis. A secondary electron image was taken of each pollen grain and EDS spectra were obtained for individually adsorbed particles. All images were analysed and the size parameters of the particles adsorbed to pollen was determined. The measured particles equivalent diameter varied between 0.1 and 25.8xa0μm, mostly in the fine fraction. The dominant particulates identified were Si-rich, Organic-rich, SO-rich, Metals & Oxides and Cl-rich. Significant daily differences were observed in the physical-chemical characteristics of particles adsorbed to the airborne pollen wall. These differences were correlated with weather parameters and atmospheric PM concentration. Airborne pollen has the ability to adsorb fine particles that may enhance its allergenicity.

Air Quality Modelling to Support Decision-Making: Scenario and Optimization Approaches

In this work a multi-objective approach to define air quality policies is proposed based on the RIAT+ (Regional Integrated Assessment Modelling Tool) system. The solutions of the decision problem represent cost-effective policies at the sectorial level. The methodology is being applied to the Porto urban area, one of the most polluted areas in Portugal, and optimal control policies up to 2020 will be selected.

Airborne Platanus Pollen Analysis by EPMA

Particles of anthropogenic and biological origin, minerals and gaseous elements are the major constituents of the aerosol. Pollen is a biological component of the aerosol, found in suspension with other pollutants. In recent years, research has been conducted on the crossed effects between non-biological and biological pollutants on allergy worsening in susceptible individuals or on the development of symptoms in non-symptomatic ones. Platanus spp pollen is abundantly present in the atmosphere of Porto in early spring and is known to promote allergic respiratory symptoms. The aim of this study was to characterize possible alterations of the main elements present on the Platanus spp. pollen wall under different atmospheric conditions in the coastal city of Porto, Portugal, using EPMA.