The urban site (39◦5803300 N 116◦2204100 E) is located in the tower section of the IAP, Chinese Academy of Sciences, where the 325m meteorological tower is located.

The site, between the fourth and third north ring roads of Beijing (Fig. 1), is in a residential area. Typical of central Beijing, there are various roads nearby.

To the south, north and west ends there are roads about 150 m away. On site, there are two to three floor buildings to the south, and the east and west ends of the tower are surrounded by small trees and grass.

There is a canal right to the north of the site. Further to the west is a park covered mainly by conifer pine trees (Yuan Dynasty Wall Heritage Park).

Table 1. Atmospheric Measurements for AIRPOLL

Technique   Parameters Operator, PI Reference
Tower (Gradient)        
Sensors NO, NO2, O3, CO, CO2, total VOCs, size segregated aerosol Cambridge, Kalberer Mead et al. 2013
PTR-ToF-MS Gradients of Speciated VOCs  GIGCAS (Wang) Shaw et al., 2015
Urban (ground)        
HR-TOF-AMS PM1 nonrefractory aerosol (PMF/ME-2)  IAP, Sun Huang et al. 2010
ACSM PM1 nonrefractory aerosol (long term; ME-2)  IAP, Sun Sun et al. 2012
SP2 BC attributed to traffic and solid fuel sources  Tsinghua, He Liu et al., 2014b
FIGAERO-CIMS Molecular identification of particle and gas phase species (oxygenated/nitrogenated)  Manchester, Allan Lopez-Hilfiker et al., 2014
SMPS/APS Size distributed aerosol number  Tsinghua, He Harrison et al., 2011
SPAMS Single particle composition – ART2A clustering  Peking, Zheng Bi et al., 2011
Xact Online PM elemental composition Peking, Zheng   
Aethalometer Equivalent BC (7 wavelength) IAP, Li   
GC×GC-FID Speciated VOCs; 15 OVOC (C2-C7); total C8-C13 aliphatics, C4 aromatics, monoterpenes  Hamilton, York Dunmore et al., 2015
OPR Oxidant Formation Birmingham, Bloss  Cazorla et al., 2010
Online OC/EC Sunset OCEC Carbon Aerosol Analyzer Peking, Zheng    
GC-FID Speciated VOCs (C2 – C9), lightweight OVOCs Hamilton, York Hopkins et al.,2011
PM samplers, incl. streaker sampler PM samples for chemical analysis (WP2) Peking, Zheng; Birmingham, Shi Yin et al., 2015 
Tower (flux)      
Chemiluminescence/PL converter NO and NO2 flux York, Lee Lee et al., 2015  
PTR-ToF-MS (high resolution; high frequency Flux of speciated VOCs, including the anthropogenic and biogenic tracer VOCs GIGCAS, Wang; Lancaster, Hewitt Park et al., 2013; Shaw et al., 2015

Table 2. Atmospheric Measurements for AIRPRO

Species Technique Institution   PIs/collaborators
Meteorological tower  325 m, 18 layers, w/s, dir, T andRH for 15 layers, turbulence/sonicprobes at 47 m, 140 m and 260 m  IAP  Fu, Sun, Wang
Key pollutants       
NOx, SO2 , O3 , CO Thermo instruments ICCAS Tong 
NOx, SO2 , O3 , CO, CO2 Thermo instruments Peking Wu 
Radicals and properties       
OH, HO2 , RO2 , OH reactivity FAGE (2) Leeds & Peking Heard, Whalley & Lu 
NO3 /N2O5 (also NO2 ) CRDs (3 instruments) CAS AIOFM Xie 
NO3 /N2O5 , (also NO2 , HONO andaerosol extinction) BBCEAS UCamb Jones, Ouyang 
Chemical p(O3 ) OPR (Ozone Production) UoB Bloss 
Organic gases       
C1- C8 NMHC, C1-C4 OVOC hourly Dual Channel GCFID  NCAS/York Lewis 
C8-C15 VOCs and OVOCs hourly GCxGCFID  York Lewis 
Selected VOCs (10.1Hz)  PTRMS  ICCAS Tong 
HCHO Fibre laser Leeds Heard, Ingham 
ROOH, RCOOH, peracids, HX, XO TOFCIMS  UMAN Percival 
Gas aerosol VOC GCMS  IAP Fu, Sun, Wang 
Stable C/H/N isotopes GC/irMS (MAT253) IAP Fu, Sun, Wang 
Oxidised nitrogen       
HONO LOPAP (multiple) ICCAS & UoB Tong, Bloss 
N2O5, HCN, HNO3 , ON, ClNO2 , PAN,PPN, MPAN QuadCIMS UMAN Percival
Isoprene Nitrates, C1-C5 alkyl nitrates GCMS UEA Reeves/Mills
Photolysis frequencies Spectral radiometer NCAS/Leeds Heard, Whalley 
j(O1 D), j(NO2 ) Filter radiometer Leeds & Peking Heard, Whalley & Wu 
Shortwave, longwave radiation Radiation sensors Reading Grimmond 
Aerosol radiative properties Prede Sky Radiometer IAP Shi, Dai 
Remote sensing       
Tropospheric VCDs and verticalprofiles including SO2, NO2, HCHO,HONO, etc). MAXDOAS(9 instruments aroundBeijing) CAS / AIOFM Xie 
Aerosol profiles, extinction LIDAR (9 = around Beijing) CAS / AIOFM Xie 
Aerosol backscatter Ceilometer Reading Grimmond 
NO2 , HCHO, AOD CitySCAN Max DOAS  Leicester Leigh, Monks 
VCDs of SO2 , NO2 , HCHO; Emission ofSO2 , NO2 , HCHO Mobile DOAS CAS / AIOFM Xie 
Scintillometry Kipp & Zonen MK2 Reading Grimmond 
Aerosol backscatter turbulence Doppler lidar NCAS/Reading Barlow
In situ PM       
PM2.5 (1 min) and PM10 TEOM, Thermo1400a Peking Wu 
Particle chemical composition (12-24h) High vol (PM2.5, PM10) Thermo Peking and IAP Fu & Wu 
Particle chemical composition (12-24h 4-Channelair sampler, Thermo Peking Wu 
Size resolved aerosol 9stagesampler (4 sets) IAP Fu, Sun, Wang 
Particle size dist. (12-24h) MOUDI Peking Wu 
Single particle (1-5min) Single particle sampler (2 sets) Peking and IAP Wu & Fu, Sun, Wang 
PM watersoluble ionic cmpds  GAC, TH Peking Wu 
EC/OC (1h) EC/OC analyzer, Custom made Peking Wu 
Carbonyls in fogwater MicroOVOCs/ PILS York Pang, Lewis 
Particle number size dist. 3-700nm SMPS/nano,SMPSCPC/UCPC Peking Wu 
Particle number size dist. 0.5-10 μm APS, TSI Peking Wu 
Particle mass size distributions Cambustion CPMA UMAN Allan, Coe 
CCN number conc (5 min) CCNc 200 Peking  Wu
Number concentration (MCPC) Brechtel IAP Sun, Wang, Fu
Black Carbon AE31, MAAP5012, AE33 Peking & IAP Hu & Sun, Wang, Wu 
Single particle BC SP2, DMT Peking  Wu
Particle scattering (5 min) Nephelometer 9003 Peking Wu 
Particle extinction and scattering CAPS PMssa IAP Sun, Wang, Wu 
Particle extinction CAPS PMext IAP Sun, Wang, Fu 
Particle scatt. and abs. (1 Hz) PAX,DMT Peking Hu 
Particle hygroscopicity HTDMA Peking Hu, Tong 
Online bioaerosol WIBS4A  IAP Fu, Sun, Wang 
Online aerosol composition  HRToFAMS(x2) IAP & Peking Fu, Sun, Wang & Hu
Aerosol N2O5 , HCN, HNO3 , organicnitrates, ROOH, RCOOH, peracids, ClNO2 , HX, XO (110min)  FIGAERO-TOF-CIMS  UMAN Percival, Allan, Coe, McFiggans