The role of volatile organic compounds in the polluted urban atmosphere of Bristol, UK

Abstract

Abstract. The results of a field campaign carried out from early spring through to the late summer of 2000, in Bristol, England, are presented. Continuous measurements of over 40 hydrocarbons have been made at an urban background site, located at Bristol University, for approximately nine months using a GC-FID system and for a selection of halocarbons for approximately one month using a GC-ECD system. In this paper we present the time-series of the nine halocarbons and selected hydrocarbons. Daytime and night-time hydroxyl radical concentrations have been estimated based on the diurnal variations of a selection of the measured hydrocarbons. The average summer daytime concentration of OH was found to be 2.5×106 molecules cm−3 and the night-time concentration to be in the range 104 to 105 molecules cm−3. In addition, the role played by certain VOCs in the formation of ozone is assessed using the POCP (Photochemical Ozone Creation Potential) concept.

Night‐time NO3 and OH radical concentrations in the United Kingdom inferred from hydrocarbon measurements

“…The alkenes chosen were a compromise between availability of data for analysis and reactivity of the alkenes. Rivett et al (2003) have shown that the method works best when the most reactive alkenes are chosen; however, in order to have consistency throughout the time period examined, we were mindful of choosing a set [OH] and k disp by using the alkane decay alone, three calculations were made using n-butane and n-pentane, n-butane and n-hexane, n-butane and n-heptane, respectively. As the reactivity of alkanes follows the order n-heptane > nhexane > n-pentane > n-butane, the estimation was more accurate for n-heptane than for the corresponding smaller alkanes.…”

“…The hydrocarbon decay method developed by Rivett et al (2003) has been used to analyse urban hydrocarbon data from four contrasting sites in the United Kingdom. Remarkably consistent results emerge from the analysis using alkenes, revealing NO 3 levels in the range 0.01-10 ppt and OH levels in the range 1 × 10 4 -1 × 10 6 molecule cm −3 , with an average of about 2 × 10 5 molecule cm −3 .…”

“…At night-time, observed alkene levels in the urban environment undergo a steady decay due to dispersion (physical removal) and chemical reactions with OH, NO 3 and O 3 (Rivett et al, 2003). The rate of decay can be written as (Rivett et al, 2003).…”

“…Hydrocarbon data are taken from the National Environmental Technology Centre NETCEN (NETCEC, Night-time NO 3 and OH radical concentrations from hydrocarbon measurements 141 Culham, Oxfordshire) data archive and analysed using the decay method outlined by Rivett et al (2003).…”

Analysis of Benzene Exposure Levels on Commuters Traveling within the Metropolitan Area of Costa Rica

“…In past years, the exposure levels of commuters to volatile organic compounds (VOCs) inside public transport modes have been reported in several urban locations in Europe, Asia and megacities such as Mexico City [1]- [4]. These studies have raised interest and serious concern about the impact of organic compounds emitted by automotive traffic on human health and air quality, which is now recognized as a major environmental problem in urban areas [5]- [7]. The available information indicates that commuting can cause elevated personal exposure to toxic VOCs, including compounds known as carcinogenic such as benzene, which is closely linked to the induction of leukemia [8] [9].…”