A variety of satellite based instruments provide SO2 and particle data for volcanoes worldwide, including Hawaii:
NASA
Site includes daily SO2 mass plus archived and time series data
NOAA
Latest OMI SO2 column (5 km) images by volcano, plus cloud and aerosol index images.
http://satepsanone.nesdis.noaa.gov/pub/OMI/OMISO2/index.html
NOAA
Used mostly for weather tracking, but also for volcanic gas emissions and lava flows. Images are acquired every 15 minutes.
http://www.ssd.noaa.gov/VAAC/kilauea/sloop-vis.html
NASA
Passes over Hawai’i twice a day, and can be useful for tracking plumes.
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=AERONET_Mauna_Loa
Consortium hosted by Belgian Institute for Space Aeronomy
Subscription service for image notification of volcanic gas and particle events from 5 instruments (OMI; Gome2; IASI; AIRS; Sciamachy)
Consortium consisting of Airbus Defence and Space, KNMI, SRON and TNO
The TROPOspheric Monitoring Instrument (TROPOMI) has UV, UVIS, NIR and SWIR on board the Copernicus Sentinel-5 Precursor satellite which will come online later in 2016.
NASA
Various types of space-based images for Kilauea.
http://earthobservatory.nasa.gov/Search/index.php?hq=&q=kilauea+plume&sa=search