kreg@epicen.UUCP (Kreg Martin) (01/23/86)
I'm a little confused about haze. My question is this: What, exactly, is haze, and why is it so common. I'm talking about the natural, non- pollution related haze that is often in the air. I'm not talking about fog or clouds, which I know are composed of water droplets that have condensed in air that has become super-saturated with water by the cooling of moist air. My guess would be that haze is composed of microscopic water particles, much smaller than those in fog. I can see that these could exist in air that is close to 100% relative humidity, but wouldn't they quickly evaporate if the air was any dryer? I'm sure that it is not this humid most of the time that I see haze in the air. Haze often persists on especially warm days, when surely the warming of the air drives the relative humidity down. Can anyone clear this mystery up for me? Kreg Martin ihnp4!pesnta!epicen!kreg
kort@hounx.UUCP (B.KORT) (01/25/86)
To learn more about Haze, look into the phenomena of the Great Smoky Mountains. Plant materials in the forest exude organic substances (e.g. the aromatic scents of a pine forest). Moisture nucleates on these substances. The result is haze. The rain forest actually *causes* rain. The nucleation of moisture generates clouds and rainfall increases over foliated areas. --Barry Kort
eugene@ames.UUCP (Eugene Miya) (01/26/86)
> I'm a little confused about haze. My question is this: What, exactly, > is haze, and why is it so common. I'm talking about the natural, non- > pollution related haze that is often in the air. I'm not talking about > fog or clouds, > My guess would be that haze is composed of microscopic water particles, > much smaller than those in fog. > Kreg Martin > ihnp4!pesnta!epicen!kreg On second reading this is more of a chemistry rather than a physics question (radiative transfer). I suggest sending mail to NCAR (greg woods or peter gross) and have them forward it to their people. Briefly: haze can include water, but the water can have such things as sulfuric and nitric acids, other heavier than air, non-colorless gases (air being around 30 g/cm^2), particulate matter (lead for instance) which serve as condensation nuclei. From the Rock of Ages Home for Retired Hackers: --eugene miya NASA Ames Research Center {hplabs,ihnp4,dual,hao,decwrl,allegra}!ames!aurora!eugene emiya@ames-nas.ARPA
cramer@kontron.UUCP (Clayton Cramer) (01/28/86)
> I'm a little confused about haze. My question is this: What, exactly, > is haze, and why is it so common. I'm talking about the natural, non- > pollution related haze that is often in the air. I'm not talking about > fog or clouds, which I know are composed of water droplets that have > condensed in air that has become super-saturated with water by the > cooling of moist air. > > My guess would be that haze is composed of microscopic water particles, > much smaller than those in fog. I can see that these could exist in air > that is close to 100% relative humidity, but wouldn't they quickly > evaporate if the air was any dryer? I'm sure that it is not this humid > most of the time that I see haze in the air. Haze often persists on > especially warm days, when surely the warming of the air drives the > relative humidity down. > > Can anyone clear this mystery up for me? > > Kreg Martin Part of what makes the Great Smoky Mountains in the East so hazy is the presence of xylenes, a class of hydrocarbons produced by trees and shrubs. One of the reasons that most of the densely populated sections of California now have vapor-recovery nozzles on the gas pumps to prevent hydrocarbon emissions. When the issue first came up, the Ventura County Air Quality Management District resisted the nozzles because 75% of the hydrocarbon emissions came from trees and shrubs. (This is the origin of the garbled statistic that Reagan used several years ago. You will also recall the Democrats ragged him unmercifully for it -- after all, they knew that NOTHING bad could come from Mother Nature).
franka@mmintl.UUCP (Frank Adams) (01/29/86)
In article <318@epicen.UUCP> kreg@epicen.UUCP (Kreg Martin) writes: >I'm a little confused about haze. My question is this: What, exactly, >is haze, and why is it so common. I believe haze is mostly small dust particles, not water vapor. If you think about how much dust settles in an unused room over the course of a year or so you will realize that there is a fair amount of dust in the air. Frank Adams ihpn4!philabs!pwa-b!mmintl!franka Multimate International 52 Oakland Ave North E. Hartford, CT 06108