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Tang D.,Columbia University | Li T.Y.,Chongqing Medical University | Chow J.C.,Desert Research Institute | Kulkarni S.U.,Columbia University | And 6 more authors.
Environmental Pollution | Year: 2014

In Tongliang, China, a coal-fired power plant was the major pollution source until its shutdown in 2004. We enrolled two cohorts of nonsmoking women and their newborns before and after the shutdown to examine the relationship between prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) and fetal and child growth and development. PAHs were used to measure exposure to air pollution generated by the power plant. Using PAH-DNA adduct levels as biomarkers for the biologically effective dose of PAH exposure, we examined whether PAH-DNA adduct levels were associated with birth outcome, growth rate, and neurodevelopment. Head circumference was greater in children of the second cohort, compared with the first (p = 0.001), consistent with significantly reduced levels of cord blood PAH-DNA adducts in cohort II (p < 0.001) and reduced levels of ambient PAHs (p = 0.01). © 2013 Elsevier Ltd. All rights reserved. Source

Ho K.F.,Chinese University of Hong Kong | Ho K.F.,CAS Institute of Earth Environment | Ho S.S.H.,CAS Institute of Earth Environment | Ho S.S.H.,Desert Research Institute | And 4 more authors.
Aerosol and Air Quality Research | Year: 2013

Vehicular exhaust emissions are one of major sources of anthropogenic volatile organic compounds (VOCs) in urban areas of Pearl River Delta Region (PRDR). Six types of vehicle emission (VE)-dominated samples were collected at representative locations in Hong Kong in the winter of 2003. A total of 111 VOC species were quantified in the samples collected. n-Butane (31%) was the most abundant species in liquefied petroleum gas (LPG)-fueled VE-dominated samples, followed by propane (26%) and i-butane (25%). Toluene was the most abundant species in gasoline-fueled VE-dominated samples (16%), comprising about half of the quantified aromatic content. While ethene and ethyne have the greatest abundance in all diesel-fueled VE-dominated VOCs profiles (except at Tuen Mun Bus Depot). VOCs were also quantified at three roadside locations in Hong Kong. And ethene was the most abundant VOCs at roadside locations which accounted for 9.5 to 29% of the total quantified VOCs, except at Hong Kong Polytechnic University roadside monitoring station (PUX). Moreover, several VOCs were clearly in abundances in the roadside samples, namely toluene, ethyne, propane, i-butane, n-butane and i-pentane. Generally, strong and fair correlations were determined from the marker species of fuel vapor (i.e., LPG, gasoline, and diesel), which show significant fuel evaporation from vehicles in roadside environment of Hong Kong. Maximum incremental reactivity (MIR) was also calculated to evaluate the contributions of individual VOCs to ozone (O3) formation potential. The largest contributors to O3 production at Mong Kok roadside station (MKX) and Lok Ma Chau roadside station (LMX) were toluene (17 and 15% of the measured VOC reactivity, respectively), ethene (14 and 17% of the measured VOC reactivity, respectively), and propene (7 and 8% of the measured VOC reactivity, respectively), indicating the important roles of alkenes and aromatics in the ambient O3 formation. © Taiwan Association for Aerosol Research. Source

Ho S.S.H.,CAS Institute of Earth Environment | Ho S.S.H.,Desert Research Institute | Ho K.F.,CAS Institute of Earth Environment | Ho K.F.,Hong Kong Polytechnic University | And 7 more authors.
Journal of the Air and Waste Management Association | Year: 2012

Vehicular emission (VE) is one of the important anthropogenic sources for airborne carbonyls in urban area. Six types of VE-dominated samples were collected at representative locations in Hong Kong where polluted by a particular fueled type of vehicles, including (i) a gas refilling taxis station (liquefied petroleum gas [LPG] emission); (ii) a light-duty passenger car park (gasoline emission); (iii) a minibus station (diesel emission); (iv) a single-deck-bus depot (diesel emission); (v) a double-deck-bus depot (diesel emission); and (vi) a whole-food market entrance for light- and heavy-duty vehicles (diesel emission). A total of 15 carbonyls in the samples were quantified. Formaldehyde was the most abundant carbonyl among the VE-dominated samples, and its contribution to the total quantified amount on a molar basis ranged from 54.8% to 60.8%. Acetaldehyde and acetone were the next two abundant carbonyls. The carbonyls were quantified at three roadside locations in Hong Kong. The highest concentrations of formaldehyde and acetaldehyde, 22.7 ± 8.4 and 6.0 ± 2.8 μg/m3, respectively, were determined in the samples collected at a main transportation gate for goods between Hong Kong and Mainland China. The total quantified carbonyl concentration, 37.9 ± 9.3 μg/m3, was the highest at an entrance of a cross-harbor tunnel in downtown area. The theoretical carbonyls compositions of the three roadside locations were estimated according to the VE-dominated sample profiles and the statistics on vehicle numbers and types during the sampling period. The measured compositions of formaldehyde were much higher than the theoretical compositions in summer, demonstrating that photochemical reactions significantly contributed to the formaldehyde production in the roadsides. © 2012 Copyright 2012 A&WMA. Source

Huang Y.,Hong Kong Polytechnic University | Hang Ho S.S.,CAS Institute of Earth Environment | Hang Ho S.S.,Desert Research Institute | Ho K.F.,CAS Institute of Earth Environment | And 3 more authors.
Analytical Methods | Year: 2012

Biogenic volatile organic compounds (BVOCs) in household cleaning products play key roles in indoor air quality (IAQ) because they are precursors for secondary pollutants formation. An accurate and rapid analytical technique for their measurement is of importance. This paper describes an optimization of a method for solid-phase microextraction (SPME) coupled with gas chromatography/mass spectrometry (GC-MS) for the determination of BVOCs. SPME fibers coated with Carboxen-PDMS are used to collect 12 individual BVOCs under standard conditions with a short exposure time of 5 min. Parameters influencing the extraction processes including sampling time, temperature and relative humidity are also investigated. All of the targeted BVOCs are shown to have limits of detection (LODs) in mixing ratios ranging from 0.31-0.50 ppbv, which are two magnitudes better than the LODs reported. The method precisions are between 1.1% and 6.7%. Comparison studies were carried out on a set of four floor cleaner extracts using the SPME method and traditional liquid injection method. Good agreement of the targeted BVOCs by the two methods was demonstrated. Our results indicated that SPME can serve as a simple and rapid sample collection approach to quantify BVOCs accurately and precisely in the indoor environment. © 2012 The Royal Society of Chemistry. Source

Ho S.S.H.,CAS Institute of Earth Environment | Ho S.S.H.,Desert Research Institute | Ho S.S.H.,Hong Kong Premium Services and Research Laboratory | Ip H.S.S.,Hong Kong Premium Services and Research Laboratory | And 6 more authors.
Journal of the Air and Waste Management Association | Year: 2013

A pilot hazardous airborne carbonyls study was carried out in Hong Kong and the Mainland of China. Workplace air samples in 14 factories of various types of manufacturing and industrial operations were collected and analyzed for a panel of 21 carbonyl compounds. The factories can be classified into five general categories, including food processing, electroplating, textile dyeing, chemical manufacturer, and petroleum refinery. Formaldehyde was invariably the most abundant carbonyl compound among all the workplace air samples, accounting for 22.0-44.0% of the total measured amount of carbonyls on a molar basis. Acetone was also found to be an abundant carbonyl in workplace settings; among the selected industrial sectors, chemical manufacturers' workplaces had the highest percentage (an average of 42.6%) of acetone in the total amount of carbonyls measured in air. Benzaldehyde accounted for an average of 20.5% of the total amount of detected carbonyls in electroplating factories, but its contribution was minor in other industrial workplaces. Long-chain aliphatic carbonyls (C6-C10) accounted for a large portion (37.2%) of the total carbonyls in food-processing factories. Glyoxal and methylglyoxal existed at variable levels in the selected workplaces, ranging from 0.2% to 5.5%. The mixing ratio of formaldehyde ranged from 8.6 to 101.2 ppbv in the sampled workplaces. The observed amount of formaldehyde in two paint and wax manufacturers and food-processing factories exceeded the World Health Organization (WHO) air quality guideline of 81.8 ppbv. Carcinogenic risks of chronic exposure to formaldehyde and acetaldehyde by the workers were evaluated. The lifetime cancer hazard risks associated with formaldehyde exposure to male and female workers ranged from 2.01 × 10-5 to 2.37 × 10-4 and 2.68 × 10-5 to 3.16 × 10-4, respectively. Such elevated risk values suggest that the negative health impact of formaldehyde exposure represents a valid concern, and proper actions should be taken to protect workers from such risks. Many carbonyl species (e.g., formaldehyde, acetaldehyde, and acrolein) are air toxins and they pose public health risks. The scope of this investigation covers 21 types of carbonyls based on samples collected from 14 different workplaces. Findings of the study will not only provide a comprehensive assessment of indoor air quality with regard to workers' healthy and safety, but also establish a theoretical foundation for future formulation of intervention strategies to reduce occupational carbonyl exposures. No similar study has been carried out either in Hong Kong or the Mainland of China. © 2013 Copyright 2013 A&WMA. Source

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