Nanoparticles-A Thoracic Toxicology Perspective

A substantial literature demonstrates that the main ultrafine particles found in ambient urban air are combustion-derived nanoparticles (CDNP) which originate from a number of sources and pose a hazard to the lungs. For CDNP, three properties appear important-surface area, organics and metals. All of these can generate free radicals and so induce oxidative stress and inflammation. Inflammation is a process involved in the diseases exhibited by the individuals susceptible to the effects of PM-development and exacerbations of airways disease and cardiovascular disease. It is therefore possible to implicate CDNP in the common adverse effects of increased PM. The adverse effects of increases in PM on the cardiovascular system are well-documented in the epidemiological literature and, as argued above, these effects are likely to be driven by the combustion-derived NP. The epidemiological findings can be explained in a number of hypotheses regarding the action of NP:-1) Inflammation in the lungs caused by NP causes atheromatous plaque development and destabilization; 2) The inflammation in the lungs causes alteration in the clotting status or fibrinolytic balance favouring thrombogenesis; 3) The NP themselves or metals/organics released by the particles enter the circulation and have direct effects on the endothelium, plaques, the clotting system or the autonomic nervous system/ heart rhythm. Environmental nanoparticles are accidentally produced but they provide a toxicological model for a new class of purposely 'engineered' NP arising from the nanotechnology industry, whose effects are much less understood. Bridging our toxicological knowledge between the environmental nanoparticles and the new engineered nanoparticles is a considerable challenge

Characteristics and health implications of fine and coarse particulates at roadside, urban background and rural sites in UK

Recent studies have pointed to evidence that fine particles in the air could be significant contributors to respiratory and cardiovascular diseases and mortality. Epidemiologists looking at the health effects of particulate pollution need more information from various receptor locations to improve the understanding of this problem. Detailed information on temporal, spatial and size distributions of particulate pollution in urban areas also is important for air quality modellers as well as being an aid to decision and policy makers of local authorities. This paper presents a detailed analysis of temporal and seasonal variation of PM10 and PM2.5 levels at one urban roadside, one urban background and one rural monitoring location. Levels of PM10, PM2.5 and coarse fraction of particulates are compared. In addition, particulate levels are compared with NO2 and CO concentrations. The study concludes that PM10 and PM2.5 are closely related at urban locations. Diurnal variation in PM2.5/PM10 ratio shows the influence of vehicular emission and movement on size distribution. This ratio is higher in winter than in summer indicating a build-up or longer residence time of finer particulates or washout due to wet weather in winter. In the second part of this study, a disease burden analysis is carried out based on the dose-response relationships recommended by the UK Committee on the Medical Effects of Air Pollution. The disease burden analysis indicates that if Marylebone Road levels of PM10 were prevalent all over London, it will result in around 2.5% increase in death rates due to all causes. Whereas, if Bloomsbury levels were prevalent in London, which is more likely to occur as this is more representative of the urban background environment to which people in London are likely to be exposed, the corresponding increase would be around 1.7%. Considering this, in London, at Bloomsbury levels 973 deaths and 1515 Respiratory Hospital Admissions (RHA) are attributable to PM10 while 2140 RHA are attributable to NO2. After deducting the disease burden due to background levels at Rochester, PM10 emission caused by anthropogenic activities in London equate to 273 additional deaths and 410 additional RHA while NO2 account for additional 1205 incidences of RHA

Prevalence of childhood asthma in Istanbul, Turkey

In order to determine the asthma prevalence in 6-12-year-old schoolchildren in Istanbul, we issued 2350 questionnaires, according to ISAAC criteria, in six randomly selected city primary schools to be completed at home by parents. A total of 2232 of the questionnaires were completed, an overall response rate of 94.9%, and 2216 questionnaires were taken into consideration. The prevalence of asthma was found to be 9.8% and wheezing 15.1%. To investigate the effect of socioeconomic status on the prevalence of asthma, we evaluated the heating system at home, the place of residence, the educational levels of the mother and father, the number of people living in the house, the sharing of bedrooms, and the annual family income. In conclusion, the prevalence of childhood asthma was not affected by any of these factors. Atopic family history, food allergy, eczema, and frequent otitis media and sinusitis attacks were evaluated and found to be significant in asthma prevalence