analysis SEM-EDS air particles

Journal of the Air Pollution Control Association, 1983

PubMed, 1999

The aim of this paper is to give an overview of the research in the area of air pollution, carried out exclusively at the Institute for Medical Research and Occupational Health and performed by the scientists of the Institute. For the past fifty years, air quality has been studied at work, in the ambient air of urban and industrial areas, and in various indoor environments without occupational exposure. Methods for sampling and measuring air pollutants have been introduced or developed and verified. The behaviour and the fate of air pollutants in the environment have also been investigated. Since the primary goal of the studies was to assess the extent of human exposure to air pollutants, the data were used to calculate the risk for various population groups. A dynamic model of exposure for various population groups relied on calculations of collected data, taking into account time spent in various microenvironments. This text describes the cooperation of the Institute with other institutions and agencies on the national and international level and outlines the current and prospective activities.

Air Quality Monitoring, Assessment and Management, 2011

Aerosol is constituted by a mixture of gases and suspended particles (liquid and solid). However, the particulate phase is commonly referred to as aerosol. Aerosols have been considered to play a significant role in atmospheric chemistry physical processes, meteorology and climate change, justifying in all cases the impact on humans. Their study will add to the knowledge regarding their transport and atmospheric processes, their spatial and temporal behavior and their impact on materials, visibility, climate and human health. In this sense, the particle phase of an aerosol, called airborne particles, is of relevance to www.intechopen.com Air Quality Monitoring, Assessment and Management 346 public health due to their proven morbidity and mortality effects on humans (Pope & Dockery, 2006). The magnitude of these effects generally depends upon their seasonal behavior, sources, chemical composition, number, mass, surface area and size, which increases the human health risk when the particles are inhaled because particle size is inversely proportional to the deep deposition area in the respiratory system (Sugita et al., 2004). An essential step is to measure these variables which may all be important physicalchemical properties that influence particle toxicology (Sen et al., 2007). The risk to human health is related with a long period of exposure to environmental pollutants, which increases in children and elderly persons. Human exposure to particles for both a short-and a long-term has been associated with measures of genetic damage (Lewtas, 2007). Airborne particles can be generated through grinding activities, soil resuspension due to wind or other natural processes as soil erosion, or they can be a product of the incomplete combustion of fossil and non-fossil materials as well as a result of chemical reactions and condensation onto preexistent particles (Solomon et al., 2001). Their chemical composition is a complex mixture that depends upon several factors as emission sources, geographic and climatic conditions, atmospheric reactivity, and the like. The main process of aerosol production in nature and the most important mass-transfer via gas-phase and particle-phase is by condensation, through a supersaturated vapor initiated by the presence of small particles (heterogeneous or homogeneous nucleation) or ions that serve as sites for particle formation (Hinds, 1999). Micrometer-sized particles are strongly attached to any surface they contact through the London-van der Waals forces-, which is one of the most important adhesive forces to form aggregates (Hinds, 1999). Particle size, density and shape are some of the physical properties that influence pulmonary deposition, ground deposition rate, aging during atmospheric transport and residence time in the air. These properties help identify emission sources and /or the atmospheric formation process. Size, which ranges from 10 nm to 100 µm and is commonly analyzed by lognormal distributions, is one of the most important physical properties of the particles. It is measured in terms of the aerodynamic diameter defined as the equivalent spherical particle diameter that has a density of 1 g cm-3 with the same settling velocity as the target particle, and it is used for characterizing filtration, respiratory deposition and the performance of many types of air cleaners and air particle samplers. 3. Organic aerosol 3.1 Impact on climate and air quality Aerosol particles influence the Earth's radiative and hydrological balance (Ramanathan et al., 2001). Knowledge of their contribution to radiative forcing is still uncertain (IPCC, 2007). Soot particles, which are aggregated carbonaceous spherules of tens of nanometers in size, and which have graphitic structures, are emitted from incomplete combustion of fossil fuel, biofuel, and biomass carbon together with organic matter. Soot particles contribute to the warming effect in the atmosphere through absorption of sunlight (Bong & Bergstrom, 2006). Black carbon is found throughout the atmosphere, and it is thought to be the most important component to aerosol absorption of solar radiation although attention has recently turned to "brown" organic carbon (Sun et al., 2007) as a source of significant absorption, particularly in the near-UV. The scattering and absorption of incoming solar radiation is also affected by the organic aerosol component (Jacobson et al., 2000). Organics can alter the hygroscopicity www.intechopen.com Organic Compounds in Airborne Particles and their Genotoxic Effects in Mexico City 347 of the particles (Thomas et al., 1999), and this changes the radiative forcing that involves cloud condensation and nuclei formation; such forcing may have opposite signs depending on the type of particulate carbon (NRC, 1996). Emissions of organic species have the potential to influence aerosol-cold cloud interactions and climate (Cziczo et al., 2004). The hygroscopicity of atmospheric aerosols has a considerable effect on particle size and therefore on visibility (Vasconcelos et al., 1994). Dissolved and surface-active organic compounds in droplets and aerosols affect the albedo of clouds and rain development (Facchini et al., 1999). Size distributions as well as the optical and hydrophilic properties of organic particles are also uncertain due to the lack of data (Liousse et al., 2005), in part owing to the complexity of the organic content which may involve several hundreds of compounds of a different chemical class and which have different biological effects. Although biological particles such as spores, bacteria, algae, pollen, vegetation and insect debris, animal cell fragments, and the like (Winiwater et al., 2009) can be considered as part of the particle organic fraction, their discussion goes beyond this chapter.

Environmental Research, 2018

Particle matter (PM) and its associated compounds are a serious problem for urban air quality and a threat to human health. In the present study, we assessed the intraurban variation of PM, and characterized the human health risk associated to the inhalation of particles measured on PM filters, considering different land use areas in the urban area of Cordoba city (Argentina) and different age groups. To assess the intraurban variation of PM, a biomonitoring network of T. capillaris was established in 15 sampling sites with different land use and the bioaccumulation of Co, Cu, Fe, Mn, Ni, Pb and Zn was quantified. After that, particles were collected by instrumental monitors placed at the most representative sampling sites of each land use category and an inhalation risk was calculated. A remarkable intraurban difference in the heavy metals content measured in the biomonitors was observed, in relation with the sampling site land use. The higher content was detected at industrial areas as well as in sites with intense vehicular traffic. Mean PM 10 levels exceeded the standard suggested by the U.S. EPA in all land use areas, except for the downtown. Hazard Index values were below EPA's safe limit in all land use areas and in the different age groups. In contrast, the carcinogenic risk analysis showed that all urban areas exceeded the acceptable limit (1 × 10 −6), while the industrial sampling sites and the elder group presented a carcinogenic risk higher that the unacceptable limit. These findings validate the use of T. capillaris to assess intraurban air quality and also show there is an important intraurban variation in human health risk associated to different land use.

Aerosol and Air Quality Research, 2019

Air toxics, also well-known as hazardous air pollutants (HAPs), have significant health effects on human health and are of great concern. This paper studied a number of hazardous air pollutants in an industrial and metropolitan complex area in order to determine their ambient abundance and potential health impacts. The target pollutants in this study are benzene, formaldehyde, 1,3-butadiene, arsenic, 2,3,7,8-TCDD, and diesel particulate matter (DPM). A cancer risk assessment was conducted to determine the health effects of exposure to the six HAPs by using the AERMOD model. Results indicated that the emission of benzene, formaldehyde, 1,3-butadiene, arsenic and DPM was 184.5; 227.3; 68.0; 238, and 316 ton year-1 , respectively, and the emission of 2,3,7,8-TCDD was 4,994 mg-TEQ year-1. Benzene (86%), formaldehyde (69%), and 1,3-butadiene (77%) were mainly emitted from on-road mobile sources. Arsenic (70%) and 2,3,7,8-TCDD (about 100%) were mainly emitted from stationary sources and DPM was emitted from diesel engines, port operations and ocean-going vessels. Spatial air toxic distribution indicated that the highest concentration of DMP, benzene, formaldehyde, and 1.3-butadiene occurred on the highway and in the downtown district due to their high traffic volume. DPM occupied more than 80% of total cancer risk in the region, followed by 1,3-butadiene, benzene, formaldehyde, arsenic, and 2,3,7,8-TCDD. In the industrial and residential complex area, about 99% of the cancer risk stemmed from on-road vehicles and port operations due to hazardous air pollutant emissions, especially DPM. The control scenario was made huge efforts to reduce the emission, however the results indicated only reduced the overall cancer risk assessment by 10%-15%. Policy makers have to think carefully about whether implementing the kind of emissions regulations simulated in this control scenario will need to be enhanced with additional measures to further reduce the risk of air pollution for human health.

Encyclopedia of Sustainability Science and Technology, 2012

Aerosol A suspension of particulate matter composed of solid and/or liquid material in a gas. Carbon Dioxide (CO 2) CO 2 is a part of the atmosphere (>405 ppm), and indoor concentrations in excess of ambient are mainly generated by people, about a kilogram per day depending on metabolism. The indoor exposure limit is commonly taken as 1000 ppm, a level at which the negative health effects of CO 2 are not yet significant. CO 2 is a useful Freja Hasager and Joachim Dithmer Bjerregaard contributed equally.