Hydrocarbon source signatures in Houston, Texas: Influence of the petrochemical industry

Abstract

[1] Observations of C 1 -C 10 hydrocarbon mixing ratios measured by in situ instrumentation at the La Porte super site during the TexAQS 2000 field experiment are reported. The La Porte data were compared to a roadway vehicle exhaust signature obtained from canister samples collected in the Houston Washburn tunnel during the same summer to better understand the impact of petrochemical emissions of hydrocarbons at the site. It is shown that the abundance of ethene, propene, 1-butene, C 2 -C 4 alkanes, hexane, cyclohexane, methylcyclohexane, isopropylbenzene, and styrene at La Porte were systematically affected by petrochemical industry emissions. Coherent power law relationships between frequency distribution widths of hydrocarbon mixing ratios and their local lifetimes clearly identify two major source groups, roadway vehicle emissions and industrial emissions. Distributions of most aromatics and long chain alkanes were consistent with roadway vehicle emissions as the dominant source. Air mass reactivity was generally dominated by C 1 -C 3 aldehydes. Propene and ethene sometimes dominated air mass reactivity with HO loss frequencies often greater than 10 s À1 . Ozone mixing ratios near 200 ppbv were observed on two separate occasions, and these air masses appear to have been affected by industrial emissions of alkenes from the Houston Ship Channel. The La Porte data provide evidence of the importance of industrial emissions of ethene and propene on air mass reactivity and ozone formation in Houston.

Species profiles and normalized reactivity of volatile organic compounds from gasoline evaporation in China

“…In the present study, benzene ranged 0.71e1.37% in refueling vapors and averaged 0.44% in headspace vapors; the latter was comparable to that of 0.37% reported by Harley et al (2000) or 0.56% by Na et al (2004) in headspace vapors, but much lower than that of 4.49% previously reported in China by Liu et al (2008a). Table 2 presents ratios of paired VOCs that have been widely used to indicate relative contributions from different emission sources (Barletta et al, 2002(Barletta et al, ,2008Jobson et al, 2004;Chan et al, 2006;de Gouw et al, 2006;Karl et al, 2007;Simpson et al, 2011). Toluene to benzene (T/B) ratios ranged 2.0e5.8 in refueling vapors from the present study, and ranged 1.5e6.5 in headspace vapors from this study and previous works (Harley et al, 2000;Na et al, 2004;Liu et al, 2008a).…”

Multi-year (2004–2008) record of nonmethane hydrocarbons and halocarbons in New England: seasonal variations and regional sources

“…Moreover, the i-butane/nbutane slope (0.49-0.56, Fig. 7b) was within the range of reported emission ratios from several sources, including urban/vehicular exhaust (∼0.2-0.3), LPG (0.46), and natural gas (∼0.6 to >1) (B. Sive, unpublished data; Jobson et al, , 2004Goldan et al, 2000;Barletta et al, 2002;Choi and Ehrman, 2004;Velasco et al, 2007). Additionally, the slope of the correlation between i-pentane and n-pentane (range for each season each year=1.5-2.6) (Fig.…”

“…Additionally, the slope of the correlation between i-pentane and n-pentane (range for each season each year=1.5-2.6) (Fig. 7c) was within the range of reported emission ratios for vehicle exhaust and tunnel studies (∼2.2-3.8), liquid gasoline (1.5-3), and fuel evaporation (1.8-4.6) (Conner et al, 1995;Harley et al, 2001;Watson et al, 2001;Jobson et al, 2004;McCaughey et al, 2004;Lough et al, 2005;Velasco et al, 2007). Overall, these results suggest that a uniform mix of emissions from numerous alkane sources is observed at TF.…”

“…8b) was slightly higher, and the m+p-xylene/ethylbenzene (1.1-1.9, Fig. 8c) and oxylene/ethylbenzene (0.53-1.1, not shown) slopes were lower than industrial/urban, gasoline, fuel evaporation, and vehicle exhaust emission ratios (∼0.36-0.4, 2.2-4.6, and 1.2-1.8, respectively) (Conner et al, 1995;Kirchstetter et al, 1996;Sagebiel et al, 1996;Rogak et al, 1998;Monod et al, 2001;Watson et al, 2001;Choi and Ehrman, 2004;Jobson et al, 2004;Velasco et al, 2007). The differences between the emission and ambient C 8 aromatic ratios likely reflect the preferential loss of the xylenes during air mass transport because of their greater reactivity.…”

Ozone production in remote oceanic and industrial areas derived from ship based measurements of peroxy radicals during TexAQS 2006

“…Ryerson et al, 2003;Jobson et al, 2004;Kleinman et al, 2005) have highlighted the special chemical characteristics of the Houston/Galveston area: co-located large emissions of NO x and of highly reactive VOC (particularly light alkenes) combined with the unique meteorology described above result in some of the highest concentrations of urban ozone in the United States. Measurements of peroxy radicals in such photochemically active air masses provide a unique look into their chemistry and assists in understanding the factors that influence ozone production across the region.…”