Airborne Mites

November 24, 2005

Aerosol particles influence atmospheric chemistry, climate, and human health
They are tiny and very finely dispersed and play important roles for our climate and health. We are talking about aerosol particles, airborne droplets and solid particles on the micro- or nanometer scale. These stem from a variety of natural and anthropogenic sources: the incomplete combustion of fossil fuels, forest fires, volcanic eruptions, dispersion of dust and sea salt, in addition to biological materials such as pieces of plants, microorganisms, or pollen.

The most noticeable examples of aerosols are clouds, which consist of water droplets or ice crystals with diameters on the order of 10 µm and are formed by condensation of water vapor onto smaller particles.

“Concentration, composition, and size distribution of atmospheric aerosol particles are highly variable at different locations and times,” explains Ulrich Pöschl of the Max Planck Institute of Chemistry in Mainz in a review article in Angewandte Chemie. “The precise determination of their chemical composition is a demanding analytical challenge. Aside from several main components, there are hundreds of trace constituents and numerous chemical reactions to take into account.”

It is undisputed that aerosols have a strong influence on climate and health. The interactions and relationships are so complex, however, that it is unclear to which extent different effects and feedback loops have a strengthening or calming influence. For example, an intensification of photosynthesis and biomass production caused by the increase in atmospheric CO2 content and global warming can lead to an increase in biogenic aerosol particles. These act as nuclei for the condensation of clouds, and an increase in clouds has a cooling effect (negative feedback). On the other hand, higher temperatures can be stressful for plants, causing photosynthesis and aerosol formation to decrease. This may lead to a reduction of cloud cover and increase global warming (positive feedback).

“Very little is known about the relations between air quality and allergies,” says Pöschl. The most prominent group of airborne allergens are proteins, which constitute up to about 5 % of urban air particulate matter. In air polluted by nitrogen oxides and ozone (summer smog), proteins such as the birch pollen allergen are easily nitrated, and chemically modified proteins can strengthen physiological immune reactions. Thus the inhalation of nitrated protein aerosols appears likely to promote allergies. “If such relations are not sufficiently explored,” says Pöschl, “there is a danger that new environmental protection laws and technologies have undesirable side effects and cause more harm than good. For example, some exhaust systems for diesel vehicles remove soot particles but release more nitrogen oxides.”

Source: Angewandte Chemie

Explore further: Ocean life triggers ice formation in clouds

Related Stories

Ocean life triggers ice formation in clouds

September 9, 2015

Researchers have shown for the first time that phytoplankton (plant life) in remote ocean regions can contribute to rare airborne particles that trigger ice formation in clouds. Results published this week (Wednesday 9 September) ...

Combustion's mysterious "QOOH" radicals exposed

August 11, 2015

Researchers can now discriminate between the previously unidentified hydroperoxyalkyl radicals found in the early stages of the combustion process from similar compounds, thanks to data from the Advanced Light Source at Lawrence ...

In Africa, more smoke leads to less rain, NASA shows

August 7, 2015

A new NASA study shows that agricultural fires in North Africa reduce the region's rainfall during the dry season, in a longstanding example of humans unintentionally modifying weather and regional climate. The study is the ...

Recommended for you

The dark side of Nobel prizewinning research

October 4, 2015

Think of the Nobel prizes and you think of groundbreaking research bettering mankind, but the awards have also honoured some quite unhumanitarian inventions such as chemical weapons, DDT and lobotomies.

Internet giants race to faster mobile news apps

October 4, 2015

US tech giants are turning to the news in their competition for mobile users, developing new, faster ways to deliver content, but the benefits for struggling media outlets remain unclear.

Trade in invasive plants is blossoming

October 3, 2015

Every day, hundreds of different plant species—many of them listed as invasive—are traded online worldwide on auction platforms. This exacerbates the problem of uncontrollable biological invasions.

Fusion reactors 'economically viable' say experts

October 2, 2015

Fusion reactors could become an economically viable means of generating electricity within a few decades, and policy makers should start planning to build them as a replacement for conventional nuclear power stations, according ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.