Those warmer temperatures can influence an airplane’s ability to fly because air molecules (分子) spread out more as the air warms. This produces less lift under a plane’s wings, so a plane must be lighter to take off in hot weather than on cooler days. It can even prove too ...
More perilous still are smaller particles measuring under 2.5 microns across, which can be breathed deep into the lungs and can be so tiny that they even cross over into the bloodstream. WHO says concentrations of PM10 should remain below 20 microgrammes per cubic metre, averaged out over the ...
Even so, at room temperature, a cubic meter weighs 1.18 kg. Although the mean free path between collisions is 60 nm, air molecules travel at an average speed of 500 m/s at room temperature so that each one experiences 8.3 × 109 collisions per second! It is the force with which the ...
Let's consider a cubic container (see figure below) with some air closed inside. According to the kinetic theory of gases, the molecules of the gas are in constant motion with a velocity that depends on the thermal energy. Particles collide with each other and with the walls of a ...
In addition to oxygen, nitrogen, and other gases, each breath contains small amounts of particulate matter, trace elements, as well as soluble and volatile molecules. As some of these have bioactive properties, is it possible that an alternate source of nutrients has been literally right under ...
The concentrations were 20, 50 and 150 micrograms per cubic meter. While the European Union limits PM2.5 emissions to 25 micrograms per cubic meter, cities commonly have more.After each breathing experience, the volunteers donated blood samples 24 hours later. ...
PM2.5 particulates are much more dangerous (they're less than 2.5 millionths of a meter or about 40 times thinner than a typical hair). In cities, most particulates come from traffic fumes. [11] Ozone: Also called trioxygen, this is a type of oxygen gas whose molecules are made from ...
Measuring the airborne particle level before and after installing the cascaded filter system we describe here, and obtaining actual counts of airborne dust particles per cubic meter of air, we found at least an order of magnitude reduction in the dust level in the building. When we compared befo...
Air pollution is a worldwide public health issue: in 2015, exposure to ambient particulate matter less than 2.5 μm in diameter (PM2.5) contributed to 4.2 million deaths and 103.1 million disability-adjusted life-years.1Air pollution is a complex mixture of gaseous molecules and suspended solid...
The resulting gas molecules are ionized by electron ionization at 70 eV, and the ions formed are detected by a time-of-flight mass spectrometer according to their mass-to-charge ratio (m/z). An L-ToF-AMS has similar working principles and operation as an HR-ToF-AMS, but with an ...