Scarlett J F, Griffiths J M, Strachan D P, Anderson H R
Mid Surrey Health Authority, West Park Hospital, Epsom, Surrey.
Thorax. 1995 Jul;50(7):764-8. doi: 10.1136/thx.50.7.764.
There is concern that, despite the fall in air pollution levels since the 1950s, there may still be adverse effects at current levels. A study was carried out to investigate the association between air pollution and respiratory symptoms in 23 year old subjects in 1981.
Data on cough, phlegm, and wheeze were available on 11,552 members of the 1958 national birth cohort. Counties in the UK were ranked by annual average level of black smoke and sulphur dioxide (SO2), and then divided into five groups. The subject's county of residence determined their categorisation of pollution exposure. The association between air pollution exposure and respiratory symptoms was examined by logistic regression, adjusting for social class, sex, and smoking.
The ranges of the air pollution groups were 2.0-13.0, 13.1-18.7, 19.6-20.8, 21.0-25.8, and 26.1-55.1 micrograms/m3 for black smoke, and 7.0-36.4, 36.7-42.7, 43.0-50.5, 52.0-59.3, and 60.9-87.7 micrograms/m3 for SO2. The overall prevalences of cough, phlegm, wheezing since age 16, and wheezing in the past year were 13.3%, 10.3%, 9.4%, and 4.4%, respectively. Phlegm symptoms increased with increasing smoke levels with evidence of a plateau. Cough and wheeze were not associated with black smoke; no symptom was associated with SO2. In the subgroup with wheeze at ages 16-23 there was no effect of smoke level on phlegm.
Low ambient levels of black smoke were associated with decreased prevalence of phlegm symptoms in young adults in the UK in 1981. The effect was evident below the current EC guideline of 34-51 micrograms/m3 annual black smoke. In 1991 the annual mean smoke level for each county ranged from 3.4 to 26.5 micrograms/m3, spanning all but the last exposure group used here. This is consistent with the existence of adverse and possibly chronic effects at current levels.
人们担心，尽管自20世纪50年代以来空气污染水平有所下降，但当前水平仍可能存在不利影响。1981年开展了一项研究，以调查23岁人群中空气污染与呼吸道症状之间的关联。
1958年全国出生队列的11552名成员提供了咳嗽、咳痰和喘息的数据。英国各县按黑烟和二氧化硫（SO₂）的年平均水平排名，然后分为五组。受试者的居住县决定了他们的污染暴露分类。通过逻辑回归分析空气污染暴露与呼吸道症状之间的关联，并对社会阶层、性别和吸烟情况进行了调整。
空气污染组黑烟的范围为2.0 - 13.0、13.1 - 18.7、19.6 - 20.8、21.0 - 25.8和26.1 - 55.1微克/立方米，SO₂的范围为7.0 - 36.4、36.7 - 42.7、43.0 - 50.5、52.0 - 59.3和60.9 - 87.7微克/立方米。自16岁起咳嗽、咳痰、喘息以及过去一年喘息的总体患病率分别为13.3%、10.3%、9.4%和4.4%。咳痰症状随烟雾水平升高而增加，并有达到平稳期的迹象。咳嗽和喘息与黑烟无关；没有症状与SO₂相关。在16 - 23岁有喘息症状的亚组中，烟雾水平对咳痰没有影响。
1981年英国低环境水平的黑烟与年轻成年人咳痰症状患病率降低有关。这种影响在当前欧盟34 - 51微克/立方米的年黑烟指导标准以下就很明显。1991年各县的年平均烟雾水平在3.4至26.5微克/立方米之间，涵盖了除这里使用的最后一个暴露组之外的所有组。这与当前水平存在不利且可能是慢性影响的情况一致。
