Current listing of the air column monitor sensor board:

Wind Speed Hot wire sensor from Modern Device -- as air is blown through the arms, resistance is measured to determine wind speed http://shop.moderndevice.com/products/wind-sensor

Wind Direction A tilt-compensated compass requires that the entire unit turn in the direction that the wind is facing (hence tail/weather vein on balloon concept) LSM303 - http://www.sparkfun.com/products/10703

Barometer Measures pressure and temperature. Calculates altitude by manually setting the current sea pressure level at the location. BMP085 - https://www.adafruit.com/products/391

Temperature and Humidity DHT22 - https://www.adafruit.com/products/385

Optical Dust Sensor Sharp GP2Y1010AU0F - http://www.sparkfun.com/products/9689

VOC MiCS-5121 - http://www.e2v.com/e2v/assets/File/sensors_datasheets/metal_oxide/MICS-5121.pdf

O3 MiCS-2611 - http://www.e2v.com/e2v/assets/File/sensors_datasheets/Metal_Oxide/mics-2611.pdf

CO MiCS-5521 - http://www.e2v.com/e2v/assets/File/sensors_datasheets/metal_oxide/MICS-5521.pdf

NO2 MICS-2710 - http://www.e2v.com/e2v/assets/File/sensors_datasheets/metal_oxide/MICS-2710.pdf

XBee Series 2 Pro Wireless Radio Frequency (RF) transmitter. Up to 1-mile communication to a receiver, attached to a computer (or potentially another Arduino that is Ethernet connected) http://www.sparkfun.com/products/10419 with Antenna: http://www.sparkfun.com/products/145