231x231px|thumb|Some common air-borne spores
Aerobiology (from Greek ἀήρ, aēr, "air"; βίος, bios, "life"; and -λογία, -logia) is a branch of biology that studies the passive transport of organic particles, such as bacteria, fungal spores, very small insects, pollen grains and viruses.
Aerobiologists have traditionally been involved in the measurement and reporting of airborne pollen and fungal spores as a service to those with allergies.
Overview
The first mention of "aerobiology" was made by Fred Campbell Meier in the 1930s.
Aerosolization is the process of a small and light particles becoming suspended in moving air. Now bioaerosols, these pollen and fungal spores can be transported across an ocean, or even travel around the globe. Due to the high quantities of microbes and the ease of dispersion, Martinus Beijerinck once said "Everything is everywhere, the environment selects". This means that aeroplankton are everywhere and have been everywhere, and it solely depends on environmental factors to determine which remain. Aeroplankton are found in significant quantities even in the Atmospheric boundary layer (ABL). The effects on climate and cloud chemistry of these atmospheric populations is still under review.
NASA and other research agencies are studying how long these bioaerosols can remain afloat and how they can survive in such extreme climates. The conditions of the upper atmosphere are similar to the climate on Mars' surface, and the microbes found are helping redefine the conditions which can support life.
Dispersal of particles
The process of dispersal of aerobiological particles has 3 steps: removal from source, dispersion through air, and deposition to rest. The particle geometry and environment affect all three phases, however once it is aerosolized, its fate depends on the laws of physics governing the motion of the air.
Removal from Source
thumb|A [[puffball mushroom ejecting its spores.]]
Pollen and spores can be blown from their surface or shaken loose. Generally the wind speed required for release is higher than average wind speed. Spores can also be removed from the air from impact; the inertia of the particles will cause them to hit surfaces along their path, instead of flowing around them like air. It is typically triggered in humans by pollen and other bioaerosols. Between 10% and 30% of people in Western countries are affected. Symptoms are usually worse during pollination periods, when there is significantly more pollen aerosolized in the air.
Up to date data on pollen levels is critical for humans that have allergies. A current limitation is that many spore traps require scientists to identify and count individual pollen grains under magnification.
Effects of climate change
thumb|215x215px|Map of precipitation change at +2 °C of global warming
Scientists have predicted that the meteorological results of climate change will weaken pollen and spore dispersal barriers, and lead to less biological uniqueness in different regions. However, more studies are needed to see long term effects of climate change.