Lighting¹ a scented² candle at the end of a long day helps many of us unwind.

在漫长的一天结束时，点燃一支香薰蜡烛能帮助许多人放松。

But that flickering³ flame might not seem quite so relaxing once you know it is spreading pollution around your home.

可是，一旦你发现香薰蜡烛可能会给家里带来污染，那么这些闪烁的烛火可能就不会让人那么放松了。

Candles release carbon and metal particles which could raise the risk of heart and lung problems, a study has warned.

一项研究提醒，蜡烛释放的碳和金属颗粒会增加患心肺疾病的风险。

The scented candle market is worth £90million in Britain and they have become a favourite gift, used to freshen living rooms or add a gentle glow to bathtimes.

在英国，香薰蜡烛的市场价值约为9000万英镑（约合人民币8亿元），香薰已经成为最受欢迎的礼物，它可以让客厅的空气变得清新，也可以在洗澡时增添一些柔和的情调。

But the US study found burning candles of any type in the home increases particles of pollution by 30 percent – and opening doors and windows does very little to help.

但是，这项美国研究发现，在室内燃烧任意种类的蜡烛都会增加30%的污染颗粒，而打开门窗也无济于事。

Frying and burning food have the same effect. So lighting a scented candle after burning the dinner might only make matters worse.

油炸和烧烤食物也会产生同样的影响。所以，做完晚饭后再点上一支香薰蜡烛只会让屋内空气变得更糟。

Lead author Dr Neil Klepeis, from San Diego State University, said he wants to help families reduce exposure to pollutants⁴, especially if there are children in the house.

这份研究报告的第一作者是圣地亚哥州立大学的尼尔•克雷派斯博士，他表示，自己想帮助人们减少家中的污染，尤其是那些家里有孩子的家庭。

Environmental scientist Professor Barbara Maher, from the University of Lancaster, was not surprised at the US team's findings.

兰卡斯特大学的环境科学家芭芭拉•马赫教授对这个美国研究团队的发现并不意外。

'My research team have directly measured the particles released by candles and found they contain carbon compounds and metals, the latter most probably from the industrial production process,' she said.

她说：“我的研究小组直接测量了蜡烛燃烧释放的颗粒，发现其中含有碳化合物以及金属，后者很可能来自（蜡烛的）工业生产过程。”

'This has made me change my own behaviour – I used to like to light a scented candle at home but now think it is a bad idea. We don't know exactly what harm these particles cause but they force the body to launch an inflammatory response to clear them. Indoor pollution is likely to be linked to the same health problems, from lung cancer to strokes, that we see from outdoor pollution.'

“这让我改变了自己的行为——过去，我喜欢在家里点一支香熏蜡烛，但是现在我发现这样做是不对的。我们不知道这些颗粒有什么确切的危害，但是为了清除这些颗粒，身体会产生炎症。室内污染引发的健康问题可能和室外污染差不多，比如肺癌、中风等。”

The US researchers scanned 300 family homes for pollution including fine particles between 0.5 and 2.5 micrometres in size – a range that includes dust, fungal spores⁵ and vehicle emissions⁶.

来自美国的研究人员对300个家庭房屋中0.5-2.5微米的细微颗粒进行了测试，这个范围内的细微颗粒包括灰尘、真菌孢子和机动车尾气。

Smoking at home was found to be the major source of airborne pollution. But burning candles and frying food with oil raised levels by almost a third.

研究发现，室内吸烟是主要的空气污染源。而燃烧蜡烛和油炸食物将空气中的污染水平提高了近1/3。

Air pollution expert Professor Ian Colbeck, from the University of Essex. said he believed the risk of health problems was the same for scented and unscented candles.

埃塞克斯大学的空气污染专家伊恩•科尔贝克教授称，香薰蜡烛和无味蜡烛引发健康问题的风险是相同的。

The US study, published in the journal PLOS ONE, concluded that indoor pollution was even worse for big families living in small houses.

这项美国研究已经发表在《公共科学图书馆•综合》期刊上，该研究认为，当一大家人生活在一所小房子里时，室内污染甚至会更严重。