Williams, K R; Ciupek, K; Tompkins, J T; Brown, A S; Allerton, J J; Butterfield, D M; Kean, M N; Robins, C C; Schmeer, J L; Singh, G K; Tipler, J M; Tomson, M; Walker, D J W; Priestman, M D S; Tremper, A H; Ek, D E B; Green, D C (2025) Airborne Particle Concentrations, Particle Numbers and Black Carbon in the United Kingdom - Annual Report 2024. NPL Report. ENV 61

Tompkins, J T; Allerton, J J; Williams, K R; Butterfield, D M; Brown, A S (2025) Particle size comparison between TSI 3936 scanning mobility particle sizer and TSI 3938W50-CEN scanning mobility particle sizer conducted at NPL and London Marylebone Road monitoring sites. NPL Report. ENV 62

Williams, K R; Braysher, E C; Brown, A S; Brown, R J C; Butterfield, D M; Cheong, J H L; Robins, C C; Showman, Y A (2025) The UK Heavy Metals Monitoring Network: Annual Report 2024. NPL Report. ENV 60

Braysher, E C; Brown, R J C; Brown, A S (2025) Investigation of internal standard use for short‑term drift correction in ICP-MS/MS. Accreditation and Quality Assurance, 30. pp. 221-231.

Braysher, E C; Cheong, J H L; Butterfield, D M; Brown, A S; Brown, R J C (2025) Lead Isotope Ratio Measurements for Source Identification Using Samples from the UK Heavy Metals Air Quality Monitoring Network. Atmosphere, 16 (3). 283

Williams, K R; Braysher, E C; Cheong, J H L; Robins, C C; Kantilal, V; Butterfield, D M; Lilley, A; Bradshaw, C; Brown, A S; Brown, R J C (2024) Annual Report for 2023 on the UK Heavy Metals Monitoring Network. NPL Report. ENV 55

Braysher, E C; Brown, A S; Brown, R J C; Molden, N (2024) Traceable determination of metal composition of tyres using tandem ICP-MS and benchmarking of emissions inventories. Environmental Science: Processes & Impact, 26 (2). pp. 298-304.

Brown, A S; Barker, S J; Brown, R J C; Wyche, K P; Butterfield, D M (2024) A robust regression analysis method to determine the significance of trends concentrations of heavy metals in UK ambient air and improve network design and emissions inventories. Environmental Monitoring and Assessment, 196. 101

Williams, K R; Braysher, E C; Cheong, J H L; Robins, C C; Kantilal, V; Butterfield, D M; Lilley, A; Bradshaw, C; Brown, A S; Brown, R J C (2023) Annual Report for 2022 on the UK Heavy Metals Monitoring Network. NPL Report. ENV 51

O'Loughlin, D P; Haugen, M J; Day, J; Brown, A S; Braysher, E C; Molden, N; Willis, A E; MacFarlane, M; Boies, A M (2023) Multi-element analysis of tyre rubber for metal tracers. Environment International, 178. 108047

Littlefair, J E; Allerton, J J; Brown, A S; Butterfield, D M; Robins, C; Economou, C K; Garrett, N R; Clare, E L (2023) Air-quality networks collect environmental DNA with the potential to measure biodiversity at continental scales. Current Biology, 33 (11). pp. R426-R428.

Goddard, S L; Williams, K R; Brown, R J C; Butterfield, D M; Robins, C; Lilley, A; Bradshaw, C; Sweeney, B; Brown, A S; Sims, A (2023) Annual Report for 2020 on the UK Heavy Metals Monitoring Network. NPL Report. ENV 48

Williams, K R; Goddard, S L; Braysher, E C; Brown, R J C; Butterfield, D M; Robins, C; Lilley, A; Bradshaw, C; Sweeney, B; Brown, A S (2023) Annual report for 2021 on the UK Heavy Metals Monitoring Network. NPL Report. ENV 49

Leni, Z; Ess, M N; Keller, A; Allen, J D; Hellen, H; Saarnio, K; Williams, K R; Brown, A S; Salathe, M; Baumlin, N; Vasilatou, K; Geiser, M (2022) Role of secondary organic matter on soot particle toxicity in reconstituted human bronchial epithelia exposed at the air-liquid interface. Environmental Science & Technology, 56 (23). pp. 17007-17017.

Brown, R J C; Goddard, S L; Williams, K R; Robins, C; Butterfield, D M; Brown, A S (2022) Falling nickel concentrations in ambient air in South Wales – 50 years of progress. Environmental Science: Processes & Impacts, 24 (10). pp. 1821-1829.

Potts, D A; Ferranti, E J S; Timmis, R; Brown, A S; Vande Hey, J D (2021) Satellite data applications for site-specific air quality regulation in the UK: Pilot study and prospects. Atmosphere, 12 (12). 1659

Brewer, P J; Downey, M L; Atkins, E; Brown, R J C; Brown, A S; Zalewska, E T; van der Veen, A M H; Smeulders, D E; McCallum, J B; Satumba, R T; Kim, Y D; Kang, N; Bae, H K; Woo, J C; Konopelko, L A; Popova, T A; Meshkov, A V; Efremova, O V; Kustikov, Y (2018) International comparison CCQM-K119 liquefied petroleum gas. Metrologia, 55 (1A). 08004 ISSN 0026-1394

van der Veen, A M H; van der Hout, J W; Ziel, P R; Oudwater, R J; Fioravante, A L; Augusto, C R; Brum, M C; Uehara, S; Akima, D; Bae, H K; Kang, N; Woo, J-C; Liaskos, C E; Rhoderick, G C; Jozela, M; Tshilongo, J; Ntsasa, N G; Botha, A; Brewer, P J; Brown, A S; Bartlett, S; Downey, M L; Konopelko, L A; Kolobova, A V; Pankov, A A; Orshanskaya, A A; Efremova, O V (2017) International comparison CCQM-K111—propane in nitrogen. Metrologia, 54 (1A). 08009 ISSN 0026-1394

Bacquart, T; van der Veen, A M H*; Bartlett, S; Ent, H*; van Wijk, J I T*; Minarro, M D; Hill-Pearce, R E; Brewer, P J; Brown, R J C; Brown, A S; Murugan, A (2017) Euramet 1220: International comparability on hydrogen purity analysis. NPL Report. ENV 16

Haloua, F*; Foulon, E*; El-Harti, E*; Sarge, S M*; Rauch, J*; Neagu, M*; Brown, A S; Tuma, D* (2016) Comparison of traceable methods for determining the calorific value of non-conventional fuel gases. Int. J. Therm. Sci., 100. pp. 438-447.

Lee, S*; Heo, G S*; Kim, Y*; Oh, S*; Han, Q*; Wu, H*; Konopelko, L A*; Kustikov, Y A*; Kolobova, A V*; Efremova, O V*; Pankratov, V V*; Pavlov, M V*; Culleton, L P; Brown, A S; Brookes, C; Li, J R*; Ziel, P R*; van der Veen, A M H* (2016) International key comparison CCQM-K94 (10 µmol/mol dimethyl sulfide in nitrogen). Metrologia, 53 (1A). 08002.

Gieseking, B*; Brown, A S (2016) Novel algorithm for calculating the methane number of liquefied natural gas with defined uncertainty. Fuel, 185. pp. 932-940.

Arrhenius, K*; Brown, A S; van der Veen, A M H* (2016) Suitability of different containers for the sampling and storage of biogas and biomethane for the determination of the trace-level impurities - a review. Anal. Chim. Acta, 902. pp. 22-32.

Goddard, S L; Brown, R J C; Butterfield, D M; McGhee, E A; Robins, C; Brown, A S; Beccaceci, S; Lilley, A; Bradshaw, C; Brennan, S (2015) Annual report for 2014 on the UK Heavy Metals Monitoring Network. NPL Report. ENV 2

Goddard, S L; Brown, R J C; Butterfield, D M; McGhee, E; Robins, C; Brown, A S; Beccaceci, S; Whiteside, K J; Bradshaw, C; Brennan, S (2015) Annual report for 2013 on the UK Heavy Metals Network. NPL Report. ENV 1

Hepburn, C A*; Vale, P*; Brown, A S; Simms, N J*; McAdam, E J* (2015) Development of on-line FTIR spectroscopy for siloxane detection in biogas to enhance carbon contactor management. Talanta, 141. pp. 128-136.

Brown, A S; Murugan, A; Brown, R J C (2015) Measurement of `total halogenated compounds' in hydrogen: is the ISO 14687 specification achievable? Accred. Qual. Assur., 20 (3). pp. 223-227.

Murugan, A; Brown, A S (2015) Review of purity analysis methods for performing quality assurance of fuel cell hydrogen. Int. J. Hydrog. Energy, 40 (11). pp. 4219-4233.

Brown, A S; van der Veen, A M H*; Arrhenius, K*; Murugan, A; Culleton, L; Ziel, P R*; Li, J* (2015) Sampling of gaseous sulfur-containing compounds at low concentrations with a review of best-practice methods for biogas and natural gas applications. TRAC Trends Anal. Chem., 64. pp. 42-52.

Brown, R J C; Goddard, S L; Butterfield, D M; Brown, A S; Robins, C; Mustoe, C L; McGhee, E A (2015) Ten years of mercury measurement at urban and industrial air quality monitoring stations in the UK. Atmos. Environ., 109. pp. 1-8.

Ferracci, V; Brown, A S; Harris, P M; Brown, R J C (2015) An investigation of the matrix sensitivity of refinery gas analysis using gas chromatography with flame ionisation detection. J. Chromatography A, 1383. pp. 14-150.

Downey, M L; Murugan, A; Bartlett, S; Brown, A S (2015) A novel method for measuring trace amounts of total sulphur-containing compounds in hydrogen. J. Chromatography A, 1375. pp. 140-145.

Sarantaridis, D; Goddard, S L; Hussain, D; Whiteside, K J; Hughey, P; Brown, A S; Brown, R J C; Brennan, S (2014) Annual Report for 2012 on the UK PAH monitoring and analysis network. NPL Report. AS 84

Murugan, A; Brown, A S (2014) Advancing the analysis of impurities in hydrogen by use of a novel tracer enrichment method. Anal. Methods, 6 (15). pp. 5472-5482.

Brown, A S; van der Veen, A M H*; Arrhenius, K*; Downey, M L; Kuhnemuth, D*; Li, J R*; Ent, H*; Culleton, L P* (2014) Traceable reference gas mixtures for sulfur-free natural gas odorants. Anal. Chem., 86 (13). pp. 6695-6702.

Ferracci, V; Brown, A S; Harris, P M; Brown, R J C (2013) An investigation of the matrix sensitivity of refinery gas analysis using gas chromatography with flame ionisation detection. NPL Report. AS 82

Brown, A S; Milton, M J T; Brookes, C; Vargha, G M; Downey, M L; Uehara, S*; Rodrigues Augusto, C*; de Lima Fioravante, A*; Goncalves Sobrinho, D*; Dias, F*; Woo, J C*; Kim, B M*; Kim, J S*; Mace, T*; Tothne Fuko, J*; Qiao, H*; Guenther, F*; Rhoderick, J*; Gameson, L*; Botha, A*; Tshilongo, J*; Ntsasa, N G*; Val'kova, M*; Durisova, Z*; Kustikov, Y*; Konopelko, L*; Fatina, O*; Wessel, R* (2013) CCQM-K93: Preparative comparison of ethanol in nitrogen. Final report. NPL Report. AS 80

Brown, A S; Downey, M L; Milton, M J T; van der Veen, A M H*; Zalewska, E T*; Li, J* (2013) EURAMET.QM-S6 / 1195: Bilateral comparison of liquefied hydrocarbon mixtures in constant pressure (piston) cylinders. NPL Report. AS 76

Culleton, L P; Brown, A S; Murugan, A; van der Veen, A*; Van Osselen, D*; Ziel, P*; Li, J*; Tuma, D*; Schulz, G*; Näther, S*; Arrhenius, K*; Kühnemuth, D*; Beránek, J*; Fuko, J*; Val'ková, M* (2013) Results of an international comparison on the analysis of real non-conventional energy gases. NPL Report. AS 77

Brown, R J C; Brown, A S (2013) Assessment of the effect of degradation by atmospheric gaseous oxidants on measured annual average benzo[a]pyrene mass concentrations. Chemosphere, 90 (2). pp. 417-422.

Brown, A S; Downey, M L; Milton, M J T; van der Veen, A M H*; Zalewska, E T*; Li, J R* (2013) Final report on EURAMET.QM-S6/1195: bilateral comparison of liquefied hydrocarbon mixtures in constant pressure (piston) cylinders. Metrologia, 50 (1A). 08015.

Brown, A S; Brown, R J C; Coleman, P J*; Conolly, C*; Sweetman, A J*; Jones, K C*; Butterfield, D M; Sarantaridis, D; Donovan, B J*; Roberts, I* (2013) Twenty years of measurement of polycyclic aromatic hydrocarbons (PAHs) in UK ambient air by nationwide air quality networks. Environ. Sci. - Process. Impacts, 15 (6). pp. 1199-1215.

Brown, R J C; Brown, A S; Kim, H* (2013) A temperature-based approach to predicting lost data from highly seasonal pollutant data sets. Environ. Sci. - Process. Impacts, 15 (6). pp. 1256-1263.

Brown, A S; Sarantaridis, D; Butterfield, D M; Brown, R J C; Whiteside, K J; Hughey, P; Goddard, S L; Hussain, D; Williams, M (2012) Annual Report for 2011 on the UK PAH Monitoring and Analysis Network. NPL Report. AS 71

Brown, R J C; Brown, A S (2012) The effect of degradation by gaseous oxidants on measured benzo[a]pyrene concentrations. NPL Report. AS 72

Brown, R J C; Butterfield, D M; Goddard, S L; Mustoe, C L; Robins, C; Brown, A S; Beccaceci, S; Whiteside, K J; Williams, M (2012) Annual report for 2011 on the UK Heavy Metals Monitoring Network. NPL Report. AS 69

Brown, R J C; Burdon, M K*; Brown, A S; Kim, K H* (2012) Assessment of pumped mercury vapour adsorption tubes as passive samplers using a micro-exposure chamber. J. Enviorn. Monit., 14 (9). pp. 2456-2463.

Brown, A S; Brown, R J C (2012) Correlations in polycyclic aromatic hydrocarbon (PAH) concentrations in UK ambient air and implications for source apportionment. J. Enviorn. Monit., 14 (8). pp. 2072-2082.

Brown, R J C; Kumar, Y; Brown, A S; Dexter, M A*; Corns, W T* (2012) Field comparison of manual and semi-automatic methods for the measurement of total gaseous mercury in ambient air and assessment of equivalence. J. Enviorn. Monit., 14 (2). pp. 657-665.

Brown, R J C; Brown, A S (2012) Principal component analysis as an outlier detection tool for polycyclic aromatic hydrocarbon concentrations in ambient air. Water Air Soil Pollut., 223 (7). pp. 3807-3816.

Brown, A S; Butterfield, D M; Brown, R J C; Hughey, P; Whiteside, K; Goddard, S L; Williams, M (2011) Annual Report for 2010 on the UK PAH Monitoring and Analysis Network. NPL Report. AS 62

Brown, A S; Vargha, G M; Downey, M L; Hart, N J*; Ferrier, G F*; Hall, K I* (2011) Methods for the analysis of trace-level impurities in hydrogen for fuel cell applications. NPL Report. AS 64

Brown, R J C; Butterfield, D M; Goddard, S L; Muhunthan, D; Robins, C; Brown, A S; Beccaceci, S; Williams, M (2011) Report to the Department of Environment, Food and Rural Affairs, the Welsh Government, the Department of the Environment in Northern Ireland, and the Scottish Government, by the National Physical Laboratory: Annual report for 2010 on the UK Heavy Metals Monitoring Network. NPL Report. AS 61

Milton, M J T; Vargha, G M; Brown, A S (2011) Gravimetric methods for the preparation of standard gas mixtures. Metrologia, 48 (5). pp. R1-R9.

Brown, R J C; Goddard, S L; Blakley, K C; Brown, A S (2011) Improvements to standard methodologies for the analytical determination of metals in stationary source emissions samples. J. Air Waste Manage. Assoc., 61. pp. 764-770.

Brown, R J C; Kumar, Y*; Brown, A S; Kim, K-H* (2011) Memory effects on adsorption tubes for mercury vapour measurement in ambient air: elucidation, quantification and strategies for mitigation of analytical bias. Environ. Sci. Technol., 45 (11). pp. 7812-7818.

Brown, R J C; Keates, A C*; Brown, A S (2011) Optimised determinations of water in ethanol by encoded photometric near-infrared spectroscopy: a special case of sequential standard addition calibration. Anal. Chim. Acta, 690 (1). pp. 47-52.

Brown, A S; Jones, D N; Milton, M J T; Downey, M L; Vargha, G M; van der Veen, A M H*; Ent, H*; Arrhenius, K*; Tuma, D* (2011) Towards a European infrastructure for the characterisation of energy gases. In: 2nd IMEKO TC11 International Symposium Metrological Infrastructure, 15-17 June 2011, Cavtat, Dubrovnik Riviera, Croatia.

Brown, R J C; Butterfield, D M; Goddard, S L; Muhunthan, D; Brown, A S; Beccaceci, S; Williams, M (2010) Annual Report for 2009 on the UK Heavy Metals Monitoring Network. NPL Report. AS 49

Dumarey, R*; Brown, R J C; Corns, W T*; Brown, A S; Stockwell, P B* (2010) Elemental mercury vapour in air: the origins of the 'Dumarey equation' describing the saturated mass concentration. Accred. Qual. Assur., 15 (7). pp. 409-414.

Brown, R J C; Wang, J; Brown, A S (2010) Temperature propagation through a mercury vapour calibration source and assessment of possible analytical biases caused by measurement of temperature variations. Measurement, 43 (9). pp. 1291-1298.

Brown, R J C; Goddard, S L; Brown, A S (2010) Using principal component analysis to detect outliers in ambient air monitoring studies. Int. J. Env. Anal. Chem., 90 (10). pp. 761-772.

Brown, A S; Brown, R J C; Dexter, M A*; Corns, W T*; Stockwell, P B* (2010) A novel automatic method for the measurement of mercury vapour in ambient air, and comparison of uncertainty with established semi-automatic and manual methods. Anal. Methods, 2 (7). pp. 954-966.

Brown, A S (2009) GravCalc2 (version 2.3.0) User Guide. NPL Report. AS 42

Brown, R J C; Butterfield, D M; Goddard, S L; Muhunthan, D; Brown, A S; Williams, M (2009) Annual Report for 2008 on the UK Heavy Metals Monitoring Network. NPL Report. AS 34

Corns, W T*; Stockwell, P B*; Brown, R J C; Brown, A S (2009) Determination of total mercury in ambient air using amalgamation with atomic fluorescence spectrometry. Int. Enviorn. Technol., 19 (5). pp. 26-27.

Brown, A S; Milton, M J T; Vargha, G M; Mounce, R*; Cowper, C J*; Stokes, A M V*; Benton, A J*; Lander, D F*; Ridge, A*; Laughton, A P* (2009) Measurement of the hydrocarbon dew point of real and synthetic natural gas mixtures by direct and indirect methods. Energy Fuels, 23 (3). pp. 1640-1650.

Milton, M J T; Harris, P M; Brown, A S; Cowper, C J* (2009) Normalisation of measured natural gas composition data measured by gas chromatography. Meas. Sci. Technol., 20 (2). 025101

Brown, R J C; Jarvis, K E*; Disch, B A*; Goddard, S L; Brown, A S (2009) Spatial inhomogeneity of metals in particulate matter on ambient air filters determined by LA-ICP-MS and comparison with acid digestion ICP-MS. J. Enviorn. Monit., 11 (11). pp. 2022-2029.

Brown, R J C; Brown, A S; Woods, P T; Brown, R S (2008) Ambient monitoring of benzo-a-pyrene (B[a]P) emissions at two oil refineries. Technical Report.

Brown, R J C; Brown, A S; Corns, W T*; Stockwell, P B* (2008) Accurate calibration of mercury vapour indicators for occupational exposure measurements using a dynamic mercury vapour generator. Instrum. Sci. Technol., 36 (6). pp. 611-622.

Brown, R J C; Brown, A S (2008) Accurate calibration of mercury vapour measurements. Analyst, 133 (11). pp. 1611-1618.

Brown, A S; Brown, R J C; Corns, W T*; Stockwell, P B* (2008) Establishing SI traceability for measurements of mercury vapour. Analyst, 133 (7). pp. 946-953.

Brown, R J C; Hood, D*; Brown, A S (2008) On the optimum sampling time for the measurement of pollutants in ambient atmospheres. Journal of Automated Methods and Management in Chemistry. Article ID: 814715

Brown, R J C; Yardley, R E; Muhunthan, D; Butterfield, D M; Williams, M; Woods, P T; Brown, A S; Goddard, S L (2008) Twenty-five years of nationwide ambient metals measurement in the United Kingdom: concentration levels and trends. Environ. Monit. Assess., 142 (1-3). pp. 127-140.

Brown, R J C; Goddard, S L; Brown, A S; Yardley, R E (2008) The effect of isotopic composition on the uncertainty of routine metal mass concentration measurements in ambient air. J. Auto. Methods Manage. Chem.. 504092

Brown, R J C; Brown, A S; Yardley, R E; Corns, W T*, Stockwell (2008) A practical uncertainty budget for ambient mercury vapour measurement. Atmos. Environ., 42 (10). pp. 2504-2517.

Brown, A S; Brown, R J C (2008) A study of the critical uncertainty contributions in the analysis of PCBs in ambient air. Journal of Automated Methods and Management in Chemistry, 2008. 179498

Brown, R J C; Brown, A S; Woods, P T; Brown, R S (2007) Monitoring benzo-a-pyrene (B[a]P) emissions at two oil refineries. NPL Report. AS 1

Brown, A S; Brown, R J C; Robinson, R A (2007) A novel calibration procedure for trace analytical measurements: application to the analysis of polybrominated diphenyl ethers by GC-MS. Analyst, 132 (9). pp. 922-928.

Brown, R J C; Harrision, N J; Brown, A S; Yardley, R E; Velummylum, D (2006) Report to the Department of Environment, Food and Rural Affairs by the National Physical Laboratory: annual report for 2004 on the UK Heavy Metals Network. NPL Report. DQL-AS 024

Brown, R J C; Yardley, R E; Brown, A S; Edwards, P R; Rivier, C*; Yardin, C* (2006) Analytical methodologies with very low blank levels: implications for practical and empirical evaluations of the limit of detection. Analytical Letters, 39 (6). pp. 1229-1241.

Milton, M J T; Harris, P M; Smith, I M; Brown, A S; Goody, B A (2006) Implementation of a generalized least-squares method for determining calibration curves from data with general uncertainty structures. Metrologia, 43. S291-S298

Brown, A S (2006) Standards in odorant emissions analysis. Local Authority Waste and Management (June). pp. 18-19.

Brown, A S; Yardley, R E; Quincey, P G; Butterfield, D M (2006) Studies of the effect of humidity and other factors on some different filter materials used for gavimetric measurements of ambient particulate matter. Atmos. Environ., 40. pp. 4670-4678.

Milton, M J T; Guenther, F*; Miller, W R*; Brown, A S (2006) Validation of the gravimetric values and uncertainties of independently prepared primary standard gas mixtures. Metrologia, 43. L7-L10

Brown, A S; Yardley, R E; Quincey, P G; Butterfield, D M (2005) Ambient air particulate matter: quantifying errors in gravimetric measurements. NPL Report. DQL-AS 015

Brown, R J C; Milton, M J T; Yardley, R E; Brown, A S; Rivier, C*; Yardin, C* (2005) Analytical methodologies with very low blank levels: implications for practical and empirical evaluations of the limit of detection. NPL Report. DQL-AS 014

Brown, A S; Milton, M J T; Cowper, C J*; Squire, G D*; Bremser, W*; Branch, R W* (2004) Analysis of natural gas by gas chromatography reduction of correlated uncertainties by normalisation. Journal of Chromatography A, 1040 (2). pp. 215-225.

Milton, M J T; Vargha, G; Brown, A S (2004) From normalisation to harmonisation: new methods for reducing the variability in GC analysis of natural gas. In: 3rd International Gas Analysis Symposium, 6-8 October 2004, Amsterdam, Neatherlands.

Brown, R J C; Yardley, R E; Brown, A S; Milton, M J T (2004) Sample matrix and critical interference effects on the recovery and accuracy of concentration measurements of arsenic in ambient particulate samples using Inductive Coupled Plasma Mass Spectrometry (ICP-MS). Journal of Analytical Atomic Spectroscopy, 19. pp. 703-705.

Brown, R J C; Yardley, R E; Brown, A S; Milton, M J T (2003) Inter-laboratory study of the measurement of Ni, As, Cd and Pb contents of ambient air. NPL Report. COAM 20