The contribution of cooking appliances and residential traffic proximity to aerosol personal exposure

Purpose Indoor and outdoor factors affect personal exposure to air pollutants. Type of cooking appliance (i.e. gas, electricity), and residential location related to traffic are such factors. This research aims to investigate the effect of cooking with gas and electric appliances, as an indoor source of aerosols, and residential traffic as outdoor sources, on personal exposures to particulate matter with an aerodynamic diameter lower than 2.5 μm (PM2.5), black carbon (BC), and ultrafine particles (UFP). Methods Forty subjects were sampled for four consecutive days measuring personal exposures to three aerosol pollutants, namely PM2.5, BC, and UFP, which were measured using personal sensors. Subjects were equally distributed into four categories according to the use of gas or electric stoves for cooking, and to residential traffic (i.e. houses located near or away from busy roads). Results/conclusion Cooking was identified as an indoor activity affecting exposure to aerosols, with mean concentrations during cooking ranging 24.7–50.0 μg/m3 (PM2.5), 1.8–4.9 μg/m3 (BC), and 1.4 × 104 –4.1 × 104 particles/cm3 (UFP). This study also suggest that traffic is a dominant source of exposure to BC, since people living near busy roads are exposed to higher BC concentrations than those living further away from traffic. In contrast, the contribution of indoor sources to personal exposure to PM2.5 and UFP seems to be greater than from outdoor traffic sources. This is probably related to a combination of the type of building construction and a varying range of activities conducted indoors. It is recommended to ensure a good ventilation during cooking to minimize exposure to cooking aerosols

Morphological and Chemical Characterisation of Indoor Quasi-Ultrafine Particles

Particles in the nanoscale range have intrinsic physicochemical characteristics that define their interaction with the human body and ultimately their toxicity. Whilst research has focused on engineered nanomaterials or ambient ultrafine particles, little is known about the morphology, size and elemental composition of particles in the nanoscale range collected in indoor environments, where humans spend the longest time. This study aims to characterise the physicochemical properties of quasi-ultrafine particles (qUFP), with an aerodynamic diameter <250 nm, collected with a Sioutas impactor from 5 indoor environments (3 homes and 2 offices). Morphology, size and elemental composition of individual particles were imaged using a Transmission Electron Microscope coupled with X-ray energy dispersive spectroscopy. Most of the single particles and their aggregates were of irregular shapes, and some fibrous rods, elongated rods, spheres and hexagons were also observed. ImageJ software was used to analyse the surface area, roundness and circularity of the particles, as well as individual particle diameter for the spherical particles. For the non-spherical shaped particle, the particles were manually measured to characterise the maximum Feret diameter. Particle main dimensions (i.e. diameter for spheroids and maximum Feret diameter for irregular particles) ranged from 35 ± 59 nm to 103 ± 160 nm. Shapes for non-spherical particles were assigned by visual description. Si, Fe and S were found in nanoparticles from all indoor locations. Other abundant constituents were K, Cr, Na, Ca, Cl found in 60–80% of locations. Minor constituents of indoor nanoparticles were Cu, Sn, Ti, Mo, Al, P, Be, F, Zn, Rb, Pb, Mn and Co. Sources were related to indoor emissions, e.g. printers, stainless-steel tools, electronics, cooking, house chores, particle re-suspension, aerosol and cleaning products as well as to penetration of outdoor nanoparticles from vehicular emissions, soil and secondary aerosols. Detailed investigation of the physicochemical properties of these particles can help understand their associated hazard and their fate in the human body

The structure of a minimal nn-chart with two crossings II: Neighbourhoods of Γ1∪Γn−1\Gamma_1\cup\Gamma_{n-1}

Given a 2-crossing minimal chart $\Gamma$, a minimal chart with two crossings, set $\alpha=\min\{~i~|~$there exists an edge of label $i$ containing a white vertex$\}$, and $\beta=\max\{~i~|~$there exists an edge of label $i$ containing a white vertex$\}$. In this paper we study the structure of a neighbourhood of $\Gamma_\alpha\cup\Gamma_\beta$, and propose a normal form for 2-crossing minimal $n$-charts, here $\Gamma_\alpha$ and $\Gamma_\beta$ mean the union of all the edges of label $\alpha$ and $\beta$ respectively.Comment: 57 pages, 36 figure

Evaluation of air quality at the Birmingham New Street Railway Station

Air pollution from diesel emissions is becoming an increased international concern, and whilst attention has been primarily focused on the automotive industry, concerns have also been raised about emissions from diesel rail vehicles. This paper reports an extensive series of measurements made at the Birmingham New Street station, a major rail interchange in the Midlands of England, with a mix of diesel and electric train movements, which is of particular concern because of the enclosed nature of the platforms. This study was undertaken in collaboration with Network Rail to better understand the environment in and around the station over a longer period to provide a more detailed analysis of the complex environment at the station. The station environment has been considered in terms of the European Union (EU) and Department of Environment, Food and Rural Affairs (DEFRA) limits as part of the monitoring methodology, but it should be noted that these limits do not apply in this environment as the Management of Health and Safety at Work Regulation 1999 and the Control of Substances Hazardous to Health Regulations 2002 are applicable. The monitoring campaign consisted of diffusion tube measurements to measure nitrogen dioxide at a large number of different locations throughout and around the station. These were followed by detailed measurements of oxides of nitrogen, particulate matter, carbon dioxide and black carbon (a diesel tracer) at a smaller number of sites at the platform level. The results are analysed to give concentrations over a wide variety of time scales, and long- and short-term averages. The effects of ambient wind conditions and individual train movements are also considered. Recommendations are made for possible remedial measures and for future work to more fully understand the physical mechanisms involved. </jats:p

Air quality in enclosed railway stations

In 2012, the World Health Organization's International Agency for Research on Cancer (IARC) reclassified diesel engine exhaust and related ambient air pollution to be carcinogenic and associated with increased mortality from lung cancer. This could have critical consequences for both public and occupational health in enclosed railway stations where ventilation is often inadequate. Recent policies encouraging a shift to public transport, along with increasing passenger and train numbers, have led to a variety of co-benefits, including improved health and well-being from increased walking and cycling. This paper considers the unintended consequences of a reduction of air quality in crowded enclosed railway stations and concludes with a number of possible interventions to ensure that public health is not affected, especially by air pollution from stationary diesel trains. Pollution from electric trains can also lead to poor air quality due to the production of metal-rich ultrafine particles from brake linings, friction between wheel and rail, and from overhead pantographs. Current occupational health standards are not suitable for enclosed railway stations and need to be reconsidered in the light of the IARC findings. More measurements of the levels of particulates and nitrogen dioxide in enclosed railway stations need to be undertaken and published. </jats:p

A review of chemical and physical characterisation of atmospheric metallic nanoparticles

AbstractKnowledge of the human health impacts associated with airborne nanoparticle exposure has led to considerable research activity aimed at better characterising these particles and understanding which particle properties are most important in the context of effects on health. Knowledge of the sources, chemical composition, physical structure and ambient concentrations of nanoparticles has improved significantly as a result. Given the known toxicity of many metals and the contribution of nanoparticles to their oxidative potential, the metallic content of the nanoparticulate burden is likely to be an important factor to consider when attempting to assess the impact of nanoparticle exposure on health. This review therefore seeks to draw together the existing knowledge of metallic nanoparticles in the atmosphere and discuss future research priorities in the field. The article opens by outlining the reasons behind the current research interest in the field, and moves on to discuss sources of nanoparticles to the atmosphere. The next section reviews ambient concentrations, covering spatial and temporal variation, mass and number size distributions, air sampling and measurement techniques. Further sections discuss the chemical and physical composition of particles. The review concludes by summing up the current state of research in the area and considering where future research should be focused