蔡志良,孫 在,陳秋方,楊文俊

(中國計(jì)量學(xué)院 計(jì)量測試工程學(xué)院,浙江 杭州 310018)

廚房油煙超細(xì)顆粒排放特征

蔡志良,孫 在,陳秋方,楊文俊

(中國計(jì)量學(xué)院 計(jì)量測試工程學(xué)院,浙江 杭州 310018)

利用快速遷移率粒徑譜儀(fast mobility particle sizer, FMPS3091)對(duì)燒菜時(shí)產(chǎn)生的超細(xì)油煙顆粒進(jìn)行測量.結(jié)果表明,在食用油加熱階段產(chǎn)生的顆粒物數(shù)量濃度成對(duì)數(shù)單峰分布,峰值在60～70 nm之間.放入菜后測量得到顆粒物數(shù)濃度成對(duì)數(shù)雙峰分布,其中青菜產(chǎn)生的顆粒物濃度最高,并且其平均粒徑和幾何標(biāo)準(zhǔn)差最大,分別為83.84 nm和2.62 nm;魚丸產(chǎn)生的顆粒物中位徑和幾何平均粒徑最大,分別為80.6 nm和57.98 nm,汽車尾氣的各個(gè)參數(shù)普遍比較小.通過對(duì)炒、煎和炸三種炒菜方式的測量,得出炸產(chǎn)生的顆粒物濃度最高,炒次之,煎最低,在炒菜過程中翻滾對(duì)顆粒物的產(chǎn)生影響最大.

廚房油煙;超細(xì)顆粒;數(shù)量濃度;炒菜方式

近年來,霧霾天氣愈來愈頻繁,涉及的面積也愈來愈廣泛,由此引發(fā)了廣大市民的關(guān)注.霧霾天氣是指主要包括霧和霾兩種的天氣現(xiàn)象,在夜間及清晨空氣濕度大時(shí)空氣中水珠或冰晶在天空形成霧,到了白天氣溫上升,各種固體粒子融入空氣中形成霾[1].而有關(guān)報(bào)道指出大氣中細(xì)微顆粒的來源中,機(jī)動(dòng)車尾氣是造成霧霾天氣的主要原因之一[2-4],而餐飲業(yè)的油煙占的比重達(dá)11%[5].目前國內(nèi)對(duì)油煙顆粒的研究較少,譚德生等[6]研究表明廚房產(chǎn)生的油煙顆粒中,可吸入顆粒的粒徑主要分布在1 μm以下,數(shù)量濃度峰值集中在0.063～0.109 μm之間.周亞美等[7]研究表明油煙產(chǎn)生的顆粒大小以小于10 μm為主.Wallace等[8]對(duì)家庭油煙研究表明燒飯產(chǎn)生的顆粒80%都在18～100 nm之間;Buonanno等[9]對(duì)廚房油煙排放的研究表明燃燒脂肪較多的葷菜產(chǎn)生的顆粒其直徑峰值在40～50 nm之間,而燃燒脂肪較少的蔬菜時(shí)產(chǎn)生的顆粒其直徑峰值在30 nm左右.可見,廚房油煙顆粒直徑都較小,如今油煙大多采取外排的方式以減少室內(nèi)細(xì)微顆粒的數(shù)量,不可避免的對(duì)外界空氣造成污染.國外眾多研究[10-13]都表明空氣中顆粒的濃度和人體心肺疾病有密切關(guān)系,其危害遠(yuǎn)比粗顆粒要大[14-16].

今通過模擬廚房做菜實(shí)驗(yàn),得出烹飪產(chǎn)生油煙超細(xì)微粒數(shù)濃度及粒徑分布特征,并且與汽車尾氣超細(xì)顆粒物進(jìn)行對(duì)比分析,為研究廚房油煙排放對(duì)灰霾天氣的形成的貢獻(xiàn)提供基礎(chǔ)數(shù)據(jù).

1 材料與方法

1.1 儀器

本實(shí)驗(yàn)采用的儀器是FMPS3091,該儀器由美國TSI公司生產(chǎn).FMPS3091基于EAA原理[17],以10 L/min流速工作,總共有32個(gè)分辨率通道,檢測5.6 nm至560 nm粒徑范圍.

1.2 實(shí)驗(yàn)方法

本實(shí)驗(yàn)?zāi)M廚房烹飪,分為三種炒菜方式,五種菜進(jìn)行,如表1.在煎和炸的方式中使用的油量要比炒菜放的多,特別是炸的方式中,因?yàn)檎ㄊ且巡送耆氲接椭?實(shí)驗(yàn)在一個(gè)寬敞的房間中進(jìn)行,測量儀器的進(jìn)氣口放在離鍋沿水平距離20 cm,垂直距離40 cm處.炒菜采用電磁爐,加熱溫度在160 ℃.

表1 烹飪方式

2 測試結(jié)果分析

2.1 燃油中產(chǎn)生的顆粒物粒徑分布

在燒菜前,首先會(huì)將油預(yù)熱一段時(shí)間,在此次實(shí)驗(yàn)中將油預(yù)熱30 s.如圖1為油煙顆粒在前30 s的平均粒徑分布.由圖可知其成單峰分布,峰值在60～70 nm之間.并且其大部分顆粒都集中在30～110 nm之間,如果能夠過濾掉這部分的顆粒,就能有效的減少油煙顆粒的危害.

圖1 油煙粒徑譜分布Figure 1 Lampblack particle size distribution

2.2 炒菜過程中不同狀態(tài)時(shí)的粒徑分布

炒菜主要分為放油、放菜和翻滾等幾個(gè)步驟,譚德生等[3]研究表明在放菜和翻炒時(shí)會(huì)產(chǎn)生大量油煙.在炒青菜、土豆和豬肉時(shí),顆粒物濃度分布成多峰分布.由圖2可知這三個(gè)步驟對(duì)顆粒物濃度影響的關(guān)系是:翻滾>放菜>放油.而在翻滾和放菜時(shí),青菜對(duì)顆粒物濃度的影響較大,土豆和豬肉影響較小,原因是青菜所占的面積較大.

圖2 炒菜時(shí)不同步驟的粒徑分布Figure 2 Particle size distribution of different cooking step

2.3 入菜后油煙顆粒數(shù)濃度分布

如圖3為放入菜后一分鐘內(nèi)產(chǎn)生的不同粒徑的顆粒物濃度的平均值.由圖我們可以看出其濃度成雙峰分布,第一個(gè)峰值在5 nm左右,第二個(gè)峰值在60～100 nm之間.

晞月橫了青櫻一眼，不欲多言。青櫻亦懶得和她爭辯，先扶住了富察氏，等著眼明手快的小太監(jiān)抬了軟轎來，一齊擁著富察氏進(jìn)了偏殿。

圖3 做不同菜時(shí)顆粒的粒徑分布Figure 3 Particle size distribution of different cooking

圖3中(a)、(b)、(c)三幅圖為炒菜時(shí)在一分鐘內(nèi)產(chǎn)生的顆粒物平均濃度.炒青菜時(shí)產(chǎn)生的顆粒物最多,原因可能有兩個(gè),一是青菜的密度小,表面積較大;二是青菜中含有的水分最多,水能促使油煙顆粒的產(chǎn)生.炒豬肉時(shí)產(chǎn)生的顆粒物較多,原因可能是其脂肪的含量較多.而含淀粉且密度較大的土豆產(chǎn)生的顆粒物最少.

d圖和e圖分別表示煎和炸兩種不同的做菜方式,由圖可以明顯看出油量多的炸魚丸比煎豆腐產(chǎn)生的顆粒物要多.它們的數(shù)濃度分布和炒的方式一樣成雙峰分布,峰值也相近.在煎的方式中放的油是10 g,比炒的方式多一倍,然而產(chǎn)生的顆粒物數(shù)濃度反而更小,說明在一定量的油內(nèi),翻滾產(chǎn)生油煙顆粒的貢獻(xiàn)比油量更大.

2.4 參數(shù)分析

顆粒物的性質(zhì)與其粒徑息息相關(guān)[18],表2反映了在燒這幾種菜時(shí)產(chǎn)生顆粒物粒徑的幾個(gè)參數(shù),中位徑是表示一個(gè)直徑,其中有一半顆粒物的直徑比它小,另一半比它大,由表2可知炸魚丸的中位徑最大.這幾種菜的平均粒徑的關(guān)系是:青菜>魚丸>豬肉>土豆>豆腐,說明水分多的食物產(chǎn)生的顆粒物的粒徑較大.它們的幾何標(biāo)準(zhǔn)差之間的關(guān)系是:青菜>土豆>豬肉>豆腐>魚丸.幾何標(biāo)準(zhǔn)差表示產(chǎn)生的顆粒物的離散程度,可見做青菜時(shí)產(chǎn)生顆粒的離散度最大.

表2 油煙顆粒的粒徑參數(shù)

3 汽車尾氣的對(duì)比

為了更加形象的說明油煙顆粒對(duì)環(huán)境的影響,增加了汽車尾氣實(shí)驗(yàn)做對(duì)比.機(jī)動(dòng)車尾氣實(shí)驗(yàn)通過在離排氣管口40 cm處采樣測量其顆粒物濃度,汽車為奧迪,其參數(shù)如表3所示.汽車為怠速狀態(tài),轉(zhuǎn)速為2 000 r/min.圖4為測得的汽車尾氣顆粒粒徑分布圖,由圖可知其成單峰分布,峰值在70 nm處,并且其兩端的顆粒較少.

表3 汽車參數(shù)

圖4 汽車尾氣顆粒的粒徑分布Figure 4 Particle size distribution of automotive exhaust

表4為汽車尾氣顆粒的參數(shù)值,從表中可以看出汽車尾氣顆粒的中位徑、平均粒徑、數(shù)濃度最大粒徑和幾何標(biāo)準(zhǔn)差都比炒菜實(shí)驗(yàn)中的平均值要小.

4 結(jié) 語

2)在放入菜后,其分布成雙峰分布,第一個(gè)峰值在接近5 nm處,第二個(gè)峰值在60～100 nm之間.各種菜產(chǎn)生顆粒物濃度的關(guān)系為:魚丸>青菜

表4 汽車尾氣顆粒的粒徑參數(shù)

>豬肉>土豆>豆腐.菜的表面積、水分和脂肪可能會(huì)有助于顆粒物的產(chǎn)生.在三種炒菜方式中,炸產(chǎn)生的顆粒物最多,炒次之,煎最少.

3)在炒表面積最大的青菜時(shí),其數(shù)濃度排放因子、平均粒徑和幾何標(biāo)準(zhǔn)差是最大的,中位徑最大的是用油最多的炸魚丸.

4)在與汽車尾氣顆粒的對(duì)比中,油煙顆粒的中位徑、平均粒徑、數(shù)濃度最大粒徑和幾何標(biāo)準(zhǔn)差的平均值都要大.

5)炒菜期間產(chǎn)生大量的超細(xì)油煙顆粒,測得的納米級(jí)顆粒濃度高達(dá)五次方,這些直接排放到空氣的超細(xì)微粒通過進(jìn)一步的凝并、吸濕以及大氣光化學(xué)作用形成典型的亞微米級(jí)灰霾粒子.

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The emission characteristics of ultrafine particles produced by cooking

CAI Zhiliang, SUN Zai, CHEN Qiufang, YANG Wenjun

(College of Metrology and Measurement Engineering, China Jiliang University, Hangzhou 310018, China)

The ultrafine particles (UFPs) produced during cooking were measured with the fast mobility particle sizer (FMPS). The results showed that the concentration of UFPs was logarithmic unimodel distribution in the edible oil heating stage, with the peak between 60 and 70 nm. The concentration of UFPs became logarithmic bi-modal distribution after putting in the dish. The mean particle diameter and its mean and geometric standard deviation of UFPs produced by cooking vegetable were 83.84 nm and 2.62 nm, respectively. The parameters of automobile exhaust was smaller than others. The median and geometric mean of UFPs produced in cooking fish ball were 80.6 nm and 57.98 nm, respectively. By an analysis of several cooking ways such as sauting, decocting and frying, we found that frying produced the highest UFPs, while decocting produced the least. Rolling has the most important effect on UFP production during sauting.

kitchen lampblack; ultrafine particle; number concentration; way of cooking

1004-1540(2015)01-0075-05

10.3969/j.issn.1004-1540.2015.01.014

2014-07-22 《中國計(jì)量學(xué)院學(xué)報(bào)》網(wǎng)址：zgjl.cbpt.cnki.net

國家自然科學(xué)基金資助項(xiàng)目(No.10972209)，國家自然科學(xué)基金重點(diǎn)項(xiàng)目(No.11132008)，浙江省自然科學(xué)基金資助項(xiàng)目(No.Y6090607).

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