_id	road_id      unique road segment ID
1	the_geom     road segment linestring
2	osm_id       OSM road ID
3	osm_code     OSM code
4	osm_fclass   OSM fclass / road-type
5	osm_name     OSM road name
6	osm_ref      OSM road ref
7	osm_oneway   OSM road metadata
8	osm_maxspeed OSM road metadata
9	osm_layer    OSM road metadata
10	osm_bridge   OSM road metadata
11	osm_tunnel   OSM road metadata
12	NO2points    number of measurements on this road segment
13	NO2drives    number of drive passes on this road segment
14	NO2_ugm3     NO2 concentration (median of drive pass mean) in µg/m3
15	NOpoints     number of measurements on this road segment
16	NOdrives     number of drive passes on this road segment
17	NO_ugm3      NO concentration (median of drive pass mean) in µg/m3
18	CO2points    number of measurements on this road segment
19	CO2drives    number of drive passes on this road segment
20	CO2_mgm3     CO2 concentration (median of drive pass mean) in mg/m3
21	COpoints     number of measurements on this road segment
22	COdrives     number of drive passes on this road segment
23	CO_mgm3      CO concentration (median of drive pass mean) in mg/m3
24	O3points     number of measurements on this road segment
25	O3drives     number of drive passes on this road segment
26	O3_ugm3      O3 concentration (median of drive pass mean) in µg/m3
27	PM25points   number of measurements on this road segment
28	PM25drives   number of drive passes on this road segment
29	PM25_ugm3    PM2.5 concentration (median of drive pass mean) in µg/m3