The USEPA has proposed to regulate PM(coarse) (particulate matter 2.5 to 10 microm in diameter). Exceedance of the proposed National Ambient Air Quality Standard (NAAQS) for PM(coarse) is expected within the Columbia Plateau of the Pacific Northwest United States based on the high frequency of dust storms and the large contribution of crustal material to fugitive dust in the region. The objecti...

OBJECTIVE It has been proposed that the redox activity of particles may represent a major determinant of their toxicity. We measured the in vitro ability of ambient fine particles [particulate matter with aerodynamic diameters<or=2.5 microm (PM2.5)] to form hydroxyl radicals (.OH) in an oxidant environment, as well as to deplete physiologic antioxidants (ascorbic acid, glutathione) in the natur...

Oxidative scrubbing is used to remove H2S from gas streams. A key problem in regeneration of the absorbent is the removal of fine particles of sulphur from the suspension of the scrubbing liquid. Dispersions of ultra-fine bubbles have been called "colloidal gas aphrons" or aphrons for short. These dispersions have interesting properties and it was found that they have particular advantages in t...

Among human activities, motor vehicles play the most important role in air pollution. Air pollution has negative impacts on people and on the environment. In this paper the effect of oxygen-enriched air (20.8%, 21.8%, 22.8%, 23.8% and 24.8%) and different bioethanol-gasoline blends (zero, 5%, 10%, 15%, 20% and 25%) in different engine speeds (1000 rpm, 2000 rpm and 3000 rpm) on the amount o...

BACKGROUND Ultrafine particles (<100 nm) are ubiquitous present in the air and may contribute to adverse cardiovascular effects. Exposure to air pollutants can alter miRNA expression, which can affect downstream signaling pathways. miRNAs are present both in the intracellular and extracellular environment. In adults, miR-222 and miR-146a were identified as associated with particulate matter exp...

Air pollution by particulate matter (PM) is one of the main threats to human health, particularly in large cities where levels are continually exceeded. According their source emission, geography, and local meteorology, pollutant particles vary size composition. These conditioned aerodynamic diameter thus classified as coarse (2.5–10 μm), fine (0.1–2.5 ultrafine (<0.1 degree toxicity becomes gr...

The hypothesis of hormesis - that substances that harm health at high exposures can reduce risks below background at low exposures, e.g., if they activate defenses without overwhelming them - becomes important for practical policy making if it holds for regulated substances. Recently, the U.S. EPA concluded that reductions in ambient concentrations of fine particulate matter (PM2.5) in air caus...