Volatile Organic Compound Analysis by Sorbent Tube-Thermal Desorption-Gas Chromatography: A Review

Volatile organic compounds (VOCs) play an important role in the generation of ground level ozone and secondary organic aerosol. Most tropical countries such as Malaysia, Singapore, Indonesia, Brunei experience high ozone pollution. Beside ozone, oxides of nitrogen (NOx) from vehicular emissions also play an important role in photochemical pollution. NOx, particularly nitric oxide (NO), helps to ‘clean up’ ozone concentrations close to traffic in the ambient air of urban areas. Thus, knowledge of the chemistry of ozone-VOCs-NOx and finding the sources of VOCs are crucial to proceed with an appropriate mitigation strategy. Thus, the detection of ozone precursors and related VOCs is thoroughly discussed. This review finds that the inertness, hydrophobicity, and the effect of the artefact materials are very significant factors to be explored in the selection of the sorbent materials. In the SEA region, relative humidity is relatively high and exceeds 90% during the northeast monsoon. Thus, the hydrophobic properties of the sampling material need careful consideration. Further to the effect of relative humidity (RH), the artefact effect of the material itself is a challenge to be optimized and multi-sorbent material in a single tube could be a viable choice to minimize the effect of the unwanted signal in the spectrum.

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Winter Ozone Pollution in Utah’s Uinta Basin is Attenuating

Atmosphere ◽

10.3390/atmos12010004 ◽

2020 ◽

Vol 12 (1) ◽

pp. 4

Author(s):

Marc L. Mansfield ◽

Seth N. Lyman

Keyword(s):

Ground Level ◽

Ambient Air ◽

Quality Standard ◽

Ozone Pollution ◽

Uinta Basin ◽

Concentration Data ◽

Previous Decade ◽

High Concentrations ◽

Ambient Air Quality Standard ◽

Ozone Precursor

High concentrations of ground-level ozone have been observed during wintertime in the Uinta Basin of western Utah, USA, beginning in 2010. We analyze existing ozone and ozone precursor concentration data from 38 sites over 11 winter seasons and conclude that there has been a statistically significant (p < 0.02) decline in ozone concentration over the previous decade. Daily exceedances of the National Ambient Air Quality Standard for ozone (70 ppb) have been trending downward at the rate of nearly four per year. Ozone and NOx concentrations have been trending downward at the rates of about 3 and 0.3 ppb per year, respectively. Concentrations of organics in 2018 were at about 30% of their values in 2012 or 2013. Several markers, annual ozone exceedance counts and median ozone and NOx concentrations, were at their largest values in the period 2010 to 2013 and have never recovered since then. We attribute the decline to (1) weakening global demand for oil and natural gas and (2) more stringent pollution regulations and controls, both of which have occurred over the previous decade. We also see evidence of ozone titration when snow cover is absent.

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Influence of the ambient humidity on the concentration of natural deposition-mode ice-nucleating particles

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-927-2016 ◽

2016 ◽

Vol 16 (2) ◽

pp. 927-932 ◽

Cited By ~ 3

Author(s):

M. L. López ◽

E. E. Ávila

Keyword(s):

Relative Humidity ◽

Linear Trend ◽

Ground Level ◽

Ambient Air ◽

Air Masses ◽

Ambient Relative Humidity ◽

Thermodynamic Conditions ◽

Rainy Days ◽

Deposition Mode

Abstract. This study reports measurements of deposition-mode ice-nucleating particle (INP) concentrations at ground level during the period July–December 2014 in Córdoba, Argentina. Ambient air was sampled into a cloud chamber where the INP concentration was measured at a temperature of −25 °C and a 15 % supersaturation over ice. Measurements were performed on days with different thermodynamic conditions, including rainy days. The effect of the relative humidity at ground level (RHamb) on the INP concentration was analyzed. The number of INPs activated varied from 1 L−1 at RHamb of 25 % to 30 L−1 at RHamb of 90 %. In general, a linear trend between the INP concentration and the RHamb was found, suggesting that this variability must be related to the effectiveness of the aerosols acting as INPs. From the backward trajectories analysis, it was found that the link between INP concentration and RHamb is independent of the origin of the air masses. The role of biological INPs and nucleation occurring in pores and cavities was discussed as a possible mechanism to explain the increase of the INP concentration during high ambient relative humidity events. This work provides valuable measurements of deposition-mode INP concentrations from the Southern Hemisphere where INP data are sparse so far.

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The influence of localized emittants on the concentration of volatile organic compounds in the ambient air measured close to ground level

Environmental Toxicology and Water Quality ◽

10.1002/(sici)1098-2256(1997)12:1<31::aid-tox5>3.0.co;2-9 ◽

1997 ◽

Vol 12 (1) ◽

pp. 31-37 ◽

Cited By ~ 4

Author(s):

Olf Herbarth ◽

Martina Rehwagen ◽

Olf Herbarth ◽

Alicia E. Ronco

Keyword(s):

Volatile Organic Compounds ◽

Organic Compounds ◽

Ground Level ◽

Ambient Air ◽

Volatile Organic

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Evaluation of regional simulation of surface ozone over Southeast Asia using ground-based observation at two existing Global Atmospheric Watch stations

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/880/1/012006 ◽

2021 ◽

Vol 880 (1) ◽

pp. 012006

Author(s):

Didin Agustian Permadi ◽

Nguyen Thi Kim Oanh

Keyword(s):

Air Quality ◽

Urban Areas ◽

Emission Inventory ◽

Surface Ozone ◽

Wrf Model ◽

Ambient Air ◽

Quality Standard ◽

Ozone Pollution ◽

Ozone Precursors ◽

Remote Sites

Abstract High level of ground level ozone concentrations was found in most of Southeast Asian (SEA) large cities and often exceeded the national ambient air quality standard. Ozone and PM10 are among of the critical air quality parameters that cause the unhealthy air quality index. Effort to mitigate ozone pollution is greatly complicated due to the photochemistry processes therefore photochemical smog modelling has been widely used. Surface ozone simulation in SEA was done using CHIMERE and weather research forecast (WRF) model. Emission inventory of ozone precursors was done for three countries in the domain, i.e. Indonesia, Thailand and Cambodia. Modelling performance evaluation for meteorological parameters and ozone at the SEA big cities was done in another study. This paper focused on the model evaluation conducted at the two remote sites represented by 2 (two) global atmospheric watch (GAW) remote stations of Bukit Kototabang (BKT) and Danum Valley (DNV). Evaluation result showed an overestimation of observed ozone in BKT while a contradictive result was seen in DNV station which was due to the ozone chemistry and inaccurate estimation of emissions (both anthropogenic and biogenic emission). The evaluation conducted at the remote sites was not even better than that conducted previously at the urban areas. Statistically, only mean normalized gross error and unpaired peak accuracy values that satisfy the criteria for surface ozone modelling suggesting major improvement required for ozone precursors emission inventory data.

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Contribution of atmospheric processes affecting the dynamics of air pollution in South-Western Europe during a typical summertime photochemical episode

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-849-2009 ◽

2009 ◽

Vol 9 (3) ◽

pp. 849-864 ◽

Cited By ~ 47

Author(s):

M. Gonçalves ◽

P. Jiménez-Guerrero ◽

J. M. Baldasano

Keyword(s):

Urban Areas ◽

Western Europe ◽

Diffusion Processes ◽

Process Analysis ◽

Ground Level ◽

Quantitative Information ◽

Vertical Diffusion ◽

Photochemical Pollution ◽

Atmospheric Processes ◽

High Solar Radiation

Abstract. The southern Mediterranean region frequently experiences critical levels of photochemical pollutants during summertime. In order to account for the contribution of different atmospheric processes during this type of episodes, the WRF-ARW/HERMES/CMAQ modelling system was applied with high resolution (1 km2, 33 sigma vertical layers, 1 h) to assess the different dynamics in a coastal environment and an inland-continental zone: the North-Eastern and Central Iberian Peninsula (NEIP and CIP, respectively). The former is characterized by a very complex terrain, while the latter behaves as a flat area, which clearly affects the pattern of local flows. A representative type of photochemical pollution episode (occurring over 78% of summer days) which occurred during 17–18 June, 2004 is selected as the study period. The CMAQ Integrated Process Rate provides the hourly contributions of atmospheric processes to net O3, NOx and NMVOCs concentrations. The O3 photochemical formation occurs mainly in downwind areas from the main NOx emission sources during midday. At surface level it accounts for 50 to 75 μg m−3 h−1. The urban areas and main roads, as main sources of NOx emissions, act as O3 sinks, quenching up to −200 μg m−3 per hour during the traffic circulation peaks. The O3 concentration gradient generated, larger during daytime, increases the contribution of diffusion processes to ground-level O3 (up to 200 μg m−3 h−1 fluxes, mainly from upper vertical layers). The maximum positive contributions of gas-phase chemistry to O3 occur in the coastal domain at high levels (around 500 to 1500 m a.g.l.), while in the continental domain they take place in the whole atmospheric column under the PBL. The transport of ozone precursors by advective flows determines the location of the maximum O3 surface concentrations. The O3 chemical formation involves the oxidation of less NMVOCs in the NEIP than in the CIP domains, due to differences in chemical sensitivity between these areas. The dry deposition is an important sink in the lowest layer of the model, together with vertical diffusion flows. Finally, the contributions from cloud processes, wet deposition and heterogeneous chemistry are negligible during the whole episode, characterized by a high solar radiation and neither precipitation nor cloudiness. This process analysis provides new quantitative information about the origin of the peaks of O3 and its precursors, aiding the design of abatement strategies in South-Western Europe.

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Study on the Pollution Characteristics and Sources of Ozone in Typical Loess Plateau City

Atmosphere ◽

10.3390/atmos11060555 ◽

2020 ◽

Vol 11 (6) ◽

pp. 555

Author(s):

Bin Li ◽

Zhuangzhi Zhou ◽

Zhigang Xue ◽

Peng Wei ◽

Yanjun Ren ◽

...

Keyword(s):

Nitric Oxide ◽

Loess Plateau ◽

Ground Level ◽

Photochemical Reactions ◽

Oxides Of Nitrogen ◽

Ozone Pollution ◽

Pollution Characteristics ◽

Nitric Oxide Concentration ◽

Standard Value ◽

High Level

Ground-level ozone is a secondary pollutant produced by photochemical reactions and it adversely affects plant and human health. Taiyuan City, a typical city on the loess plateau, is suffering from severe ozone pollution. We utilized the data from eight national environmental monitoring sites of Taiyuan, including concentrations of O3 and nitric oxide, and meteorological factors, such as air temperature and wind, to study the pollution characteristics and sources of ozone (O3) in Taiyuan in 2018. Results show that during 2018, the maximum value and 90th percentile of the maximum 8-h running average of O3 concentration were 257 μg/m3 and 192 μg/m3, respectively. There were 72 days where the O3 concentration exceeded the standard in 2018, which were mainly during April to August. The O3 concentration increased from March, reached a high level in April through August, and decreased significantly from September. The O3 concentrations displayed a typical “single peak” diurnal variation, which was high during the day with peak at around 13:00–15:00 and low at night. From April to August, the O3 concentrations at Jinyuan was the highest, followed by Xiaodian and Taoyuan, and the O3 concentrations at Shanglan and Nanzhai were the lowest. When the O3 concentration exceeded the standard value, Jinyuan contributed the most to the O3 pollution of Taiyuan, followed by Taoyuan and Xiaodian. High temperature and pressure, south and southwest winds can lead to an increase in O3 concentration. The O3 pollution in the Taiyuan urban area is caused by local generation, and the transportation of polluted air masses containing oxides of nitrogen (NOx) and volatile organic compounds (VOCs) emitted by industries, such as the coking and steel plants in counties of Jinzhong City in southern Taiyuan, and Qingxu County, and some counties in Lyuliang City to the southwest. In addition, the mountain winds and low nitric oxide concentration are the main reasons for the increase of O3 concentration, often observed in Shanglan at night.

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COVID-19 lockdowns highlight a risk of increasing ozone pollution in European urban areas

10.5194/acp-2020-1171 ◽

2020 ◽

Author(s):

Stuart K. Grange ◽

James D. Lee ◽

Will S. Drysdale ◽

Alastair C. Lewis ◽

Christoph Hueglin ◽

...

Keyword(s):

Urban Areas ◽

Ambient Air ◽

Pollution Monitoring ◽

Ambient Air Pollution ◽

Atmospheric Composition ◽

Mitigation Measures ◽

Ozone Pollution ◽

Urban Background ◽

Air Pollution Monitoring ◽

Business As Usual

Abstract. In March 2020, non-pharmaceutical interventions in the form of lockdowns were applied across Europe to urgently reduce the transmission of SARS-CoV-2, the virus which causes the COVID-19 disease. The near-complete shutdown of the European economy had widespread impacts on atmospheric composition, particularly for nitrogen dioxide (NO2) and ozone (O3). To investigate these changes, we analyze data from 246 ambient air pollution monitoring sites in 102 urban areas and 34 countries in Europe between February and July, 2020. Counterfactual, business as usual air quality time series are created using machine learning models to account for natural weather variability. Across Europe, we estimate that NO2 concentrations were 34 and 32 % lower than expected for traffic and urban-background locations while O3 was 30 and 21 % higher (in the same environments) at the point of maximum restriction on mobility. The European urban NO2 experienced in the 2020 lockdown was equivalent to that which might be anticipated in 2028 based on average trends since 2010. Despite NO2 concentrations decreasing by approximately a third, total oxidant (Ox) changed little, suggesting that the reductions of NO2 were substituted by increases in O3. The lockdown period demonstrated that the expected future reductions in NO2 in European urban areas are likely to lead to a widespread increase in urban O3 pollution unless additional mitigation measures are introduced.

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In situ measurements of isoprene and monoterpenes within a South-East Asian tropical rainforest

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-1189-2011 ◽

2011 ◽

Vol 11 (1) ◽

pp. 1189-1218 ◽

Cited By ~ 5

Author(s):

C. E. Jones ◽

J. R. Hopkins ◽

A. C. Lewis

Keyword(s):

Tropical Rainforest ◽

Ground Level ◽

Ambient Air ◽

Tropical Rainforests ◽

Light Conditions ◽

Mixing Ratios ◽

Volatile Organic ◽

Malaysian Borneo ◽

Good Agreement

Abstract. Biogenic volatile organic compounds (BVOCs) emitted from tropical rainforests comprise a substantial fraction of global atmospheric VOC emissions, however there are only relatively limited measurements of these species in tropical rainforest regions. We present observations of isoprene, α-pinene, camphene, Δ-3-carene, γ-terpinene and limonene, and oxygenated VOCs (OVOCs) of biogenic origin such as methacrolein, in ambient air above a~tropical rainforest in Malaysian Borneo. Daytime composition was dominated by isoprene, with an average mixing ratio of the order of ~1 ppb. γ-terpinene, limonene and camphene were the most abundant monoterpenes, with average daytime mixing ratios of 102, 71 and 66 ppt, respectively, and with an average monoterpene to isoprene ratio of 0.3 during sunlight hours, compared to 2.0 at night. Limonene and camphene abundances were seen to be related to both temperature and light conditions. In contrast, γ-terpinene emission occurred into the late afternoon/evening, under relatively low temperature and light conditions. We observe good agreement between surface and aircraft measurements of boundary layer isoprene and methacrolein above the natural rainforest, suggesting that the ground-level observations are broadly representative of isoprene emissions from this region.

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