road_id      unique road segment ID
the_geom     road segment linestring
osm_id       OSM road ID
osm_code     OSM code
osm_fclass   OSM fclass / road-type
osm_name     OSM road name
osm_ref      OSM road ref
osm_oneway   OSM road metadata
osm_maxspeed OSM road metadata
osm_layer    OSM road metadata
osm_bridge   OSM road metadata
osm_tunnel   OSM road metadata
NO2points    number of measurements on this road segment
NO2drives    number of drive passes on this road segment
NO2_ppb      NO2 concentration (median of drive pass mean) in parts per billion
NOpoints     number of measurements on this road segment
NOdrives     number of drive passes on this road segment
NO_ppb       NO concentration (median of drive pass mean) in parts per billion
CO2points    number of measurements on this road segment
CO2drives    number of drive passes on this road segment
CO2_ppm      CO2 concentration (median of drive pass mean) in parts per million
COpoints     number of measurements on this road segment
COdrives     number of drive passes on this road segment
CO_ppm       CO concentration (median of drive pass mean) in parts per million
O3points     number of measurements on this road segment
O3drives     number of drive passes on this road segment
O3_ppb       O3 concentration (median of drive pass mean) in parts per billion
PM25points   number of measurements on this road segment
PM25drives   number of drive passes on this road segment
PM25_ugm3    PM2.5 concentration (median of drive pass mean) in µg/m3