Table A1a Roadside Monitoring Sites

Site ID	Site Name	Town, City, District	Data Provider	Measurement Method	Grid Reference		Road Name	Concentration (ppb)
					E	N
2	Marylebone Road	London	National Network Site	Automatic	528100	182000	Marylebone Road	5.5
4	Regent Street	Cambridge	Cambridge City Council	Automatic BTX	545400	258000	Regent Street	1.6
15	S13 Drinks Cabin	Neath Port Talbot	Neath Port Talbot CC	Diffusion Tubes	266980	198163	Woodfield Street	3.3*
16	S14 General Store	Neath Port Talbot	Neath Port Talbot CC	Diffusion Tubes	266906	197833	Woodfield Street	2.7*
17	AUN	Southampton	National Network Site	Automatic	444000	113000		1.8
19	A3024	Southampton	Portsmouth City Council	Diffusion Tubes	443600	113300	A3024	1.4
20	A35	Southampton	Portsmouth City Council	Diffusion Tubes	438500	113400	A35	2.8
24	Colston Ave.	Bristol	Bristol City Council	Diffusion Tubes	358600	573100	Colston Ave.	3.7
25	Newfoundland Way	Bristol	Bristol City Council	Diffusion Tubes	359800	573800	Newfoundland Way	5.2
26	Whiteladies Road	Bristol	Bristol City Council	Diffusion Tubes	357500	574600	Whiteladies Road	5.0
27	Bath Road	Bristol	Bristol City Council	Diffusion Tubes	359700	572300	Bath Road	7.1
28	Old Market Street	Bristol	Bristol City Council	Diffusion Tubes	359800	573200	Old Market Street	5.1
29	J4 M56	Manchester	Manchester City Council	Diffusion Tubes	381670	387500	M56	1.3
30	Newton Street	Manchester	Manchester City Council	Diffusion Tubes	384560	398270	Newton Street	2.0
32	Town Hall	Oxford	Oxford City Council	Diffusion Tubes	451000	208000	St Aldates	3.0
33		Henley	OXCIS	Diffusion Tubes				1.3*
35	Watling Street	Bexley	LB of Bexley	Diffusion Tubes	550000	175000	A207	2.7
37	Harlesdon Police Station	Brent	LB of Brent	Diffusion Tubes	521200	184000	A407	2.4
38	High Road	Brent	LB of Brent	Diffusion Tubes	522800	184700	A407	3.2
39	Theobalds Road	Camden	LB of Camden	Diffusion Tubes	530700	181800	A5201	2.4
40	Russell Square	Camden	LB of Camden	Diffusion Tubes	530200	182000	A4200	2.1
41	Euston Road	Camden	LB of Camden	Diffusion Tubes	529800	182600	A501	3.9
44	Blackheath Hill	Greenwich	LB of Greenwich	Diffusion Tubes	538000	176700	A2	4.5
45	Banockburn Sch. Plumstead Rd	Greenwich	LB of Greenwich	Diffusion Tubes	544100	178900	A206	3.2
46	459 Westhorne Avenue	Greenwich	LB of Greenwich	Diffusion Tubes	541300	174500	A205	3.8
47	Greenwich Church Street	Greenwich	LB of Greenwich	Diffusion Tubes	538000	177700	A206	3.6
48	Hammersmith Broadway	Hammersmith	LB of Hammersmith	Diffusion Tubes	523400	178600	A315	3.6
51	Station Road	Harrow	LB of Harrow	Diffusion Tubes	515600	189000	A409	3.4
53	Pembridge Square	Kensington	LB of Kensington	Diffusion Tube	525200	180800	A4206	3.0
54	Eden Street	Kingston	LB of Kingston	Diffusion Tube	518300	169500	A307	2.4
55	Clarence Street	Kingston	LB of Kingston	Diffusion Tube	518300	169500	A307	3.3
56	Clarence Street	Kingston	LB of Kingston	Diffusion Tube	518300	169500	A307	2.6
59	Salisbury Sch, Romford Road	Newham	LB of Newham	Diffusion Tube	541900	185400	A118	2.7
63	York St, Twickenham	Richmond	LB of Richmond	Diffusion Tube	516200	173200	A305	3.3
65	Croydon Rd, Wallington	Sutton	LB of Sutton	Diffusion Tube	530100	164900	A232	2.2
71	St Dunstans Church Fleet Street	Corporation	Corporation of London	Diffusion Tube	531230	181150	A4	3.4
72	Crescent House Goswell Road	Corporation	Corporation of London	Diffusion Tube	532130	182040	A1?	2.2

* Supplied data were considered to be suffering from overestimation. The values presented here represent the modified data.