Elsevier

Atmospheric Environment

Volume 38, Issue 38, December 2004, Pages 6557-6564
Atmospheric Environment

Measurement of emissions of fine particulate organic matter from Chinese cooking

https://doi.org/10.1016/j.atmosenv.2004.08.034Get rights and content

Abstract

Cooking emissions may contribute significantly to atmospheric organic particles in urban environment in China, and thus need to be examined first for its chemical compositions and characteristics. The particulate organic emissions of the two cooking styles of Chinese cuisine, that is, Hunan Cooking and Cantonese Cooking, were characterized in Shenzhen. More than half of the PM2.5 mass is due to organic compounds, and over 90 species of organic compounds were identified and quantified, accounting for 26.1% of bulk organic particle mass and 20.7% of PM2.5. Fatty acids, diacids and steroids were the major organic compounds emitted from both styles of cooking. Of the quantified organic mass, over 90% was fatty acids. The mass of organic species, and the molecular distribution of n-alkanes and PAHs indicated the dissimilarities between the two different cooking styles, but generally the major parts of the organic particulate emissions of the two restaurants were similar, showing less difference than between Chinese and American cooking.

Introduction

One of the major fine particle sources in urban areas is the release of particulate matter due to cooking food (Cass, 1998). Investigations of sources (Hildemann et al., 1991) and chemical mass balance calculations (Schauer et al., 1996) show that the emissions from meat charbroiling and frying account for about 20% of all fine particulate organic matter or approximately 7% of total fine particle mass released into the atmosphere in Los Angeles. Most of the particles emitted from meat charbroiling contain organic compounds (Kleeman et al., 1999; McDonald et al., 2003), and the emissions depend strongly on the cooking method and food ingredients (Rogge et al., 1991).

China has the maximum population, nearly 1.3 billion, in the world, and would consume numerous foods cooked by various means everyday. For example, there are over 30 thousand restaurants in Beijing (Beijing Statistics Bureau, 2000). The Chinese kitchen possesses the most delicate culinary skills in controlling the degree of cooking (heat, temperature or duration), and especially, some dishes require much oil or lard for cooking. In addition, a wide range of seasoning is applied (Ishige, 1992). Therefore, the emission from different styles of cooking operation might make a quite significant contribution to atmospheric particles in China, especially in urban environment.

The concentrations of carbonaceous species in particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5) are very high in Beijing and Shenzhen. Organic carbon (OC) and elemental carbon (EC) roughly constitute 25% and 7% (Beijing) (Zhang, 2001) and 30% and 10% (Shenzhen) (He, 2003), respectively, of PM2.5. Besides vehicle exhaust, cooking emissions may be another important source for fine particle mass concentration.

Research on the environmental impact of Chinese cooking mainly focused on fume produced by cooking oil, which have potential adverse health effects for the presence of certain compounds, such as PAHs, heterocyclic amines and unsaturated aldehydes. It has been suggested that exposure to cooking fume is associated with increased carcinogenic risk (Qu et al., 1992; Li et al., 1994, Li et al., 2003; Chiang et al., 1997; Chen and Chen, 2001; Wu et al., 2001).

In view of this, determining the emissions of fine particulate organic matter from Chinese cooking seems to be of importance. It may help in understanding the relationship between fine particles emitted from the cooking source and ambient fine particulate matter concentrations found in ambient air samples, as well as to investigate the pollution characteristics of airborne particles. Only a few measurements have been reported (Rogge et al., 1991; Nolte et al., 1999; Schauer et al., 1999; McDonald et al., 2003), which focus on emissions from meat charbroiling, a typical American style of cooking. In addition, the emissions from cooking vegetables with seed oils were investigated (Schauer et al., 2002), since the cooking using seed oils was deemed to be an important source of n-alkanoic acids and carbonyls. However, no source identification data for molecular tracer techniques (Schauer et al., 1996) are yet available for emission by cooking in China.

The purpose of this study is to examine the molecular composition of the organic particles produced from two different styles of Chinese restaurants. Major compounds emitted as fine particles have been identified and quantified by gas chromatography/mass spectrometry (GC/MS), and these compounds also have also been measured in urban atmospheric particle samples.

Section snippets

Sampling

Shenzhen is an immigrant city and there are various Chinese cooking styles, so it is a perfect place to determine emissions from Chinese cooking. Two Chinese commercial restaurants were selected in July 2001, to investigate Chinese cooking emissions. These two styles are quite popular in China, i.e., Hunan cooking and Cantonese cooking, two of eight famous Chinese cuisine styles. Hunan Style is famous for its spicy and sour taste. Cantonese Style is usually fried, stewed or braised. Both

Fine particle mass and chemical composition

Fine particle mass concentrations were different for both cooking styles with the average concentrations of 1406.3±293.4 μg m−3 and 672.0±295.8 μg m−3 in Hunan cooking and Cantonese cooking, respectively. The concentrations of particles in the cooking emissions were roughly two to three orders of magnitude higher than the mean ambient fine particle mass concentrations in Beijing and Shenzhen. The compositions of the fine particulate matter emitted from the two restaurants are shown in Table 1. As

Conclusion

GC/MS technique was applied to determine the organic chemical compositions of particles from two different types of Chinese restaurants. Over 90 organic compounds were identified and quantified, accounting for 26.1% of bulk organic particle mass and 20.7% of PM2.5. Alkanes, fatty acids, diacids, PAHs, steroids, nonanal and levoglucosan were identified as major individual organic compounds and quantified. Of the quantified organic mass, over 90% was fatty acids, followed by diacids and steroids.

Acknowledgements

This work was funded by the “863” project (2001AA641060) from Ministry of Science and Technology, P.R. China, the National Basic Research Program (2002CB211605) and the projects supported by National Natural Science Foundation of China (20177002, 20131160731, 30230310) and research funding from Shenzhen municipal government. The authors would like to appreciate Dr. J. Slanina, Professor of the Netherlands Wageningen University, Professor of Peking University, for his useful comments and

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