Becklake M, Broder I, Chan-Yeung M, Dosman J A, Ernst P, Herbert F A, Kennedy S M, Warren P W
Department of Epidemiology and Biostatistics, McGill University, Montreal, Que.
CMAJ. 1996 Nov 15;155(10):1399-403.
To assess the appropriateness of the current Canadian standards for exposure to grain dust in the workplace.
The current permissible exposure limit of 10 mg of total grain dust per cubic metre of air (expressed as mg/m3) as an 8-hour time-weighted average exposure, or a lower permissible exposure limit.
Acute symptoms of grain-dust exposure, such as cough, phlegm production, wheezing and dyspnea, similar chronic symptoms, and spirometric deficits revealing obstructive or restrictive disease.
Articles published from 1924 to December 1993 were identified from Index Medicus and the bibliographies of pertinent articles. Subsequent articles published from 1994 (when the recommendations were approved by the Canadian Thoracic Society Standards Committee) to June 1996 were retrieved through a search of MEDLINE, and modification of the recommendations was not found to be necessary. Studies of interest were those that linked measurements of total grain dust levels to the development of acute and chronic respiratory symptoms and changes in lung function in exposed workers. Papers on the effects of grain dust on workers in feed mills were not included because other nutrients such as animal products may have been added to the grain. Unpublished reports (e.g., to Labour Canada) were included as sources of information.
A high value was placed on minimizing the biological harm that grain dust has on the lungs of grain workers.
BENEFITS, HARMS AND COSTS: A permissible exposure limit of 5 mg/m3 would control the short-term effects of exposure to grain dust on workers. Evidence is insufficient to determine what level is needed to prevent long-term effects. The economic implications of implementing a lower permissible exposure limit have not been evaluated.
The current Canadian standards for grain-dust exposure should be reviewed by Labour Canada and the grain industry. A permissible exposure level of 5 mg/m3 is recommended to control short-term effects. Further measurements that link the levels of exposure to respiratory health effects in workers across Canada should be collected to establish an exposure-response relation and possible regional differences in the effects of grain dust.
There has been no external review of these recommendations. However, the American Conference of Governmental Industrial Hygienists has recommended an 8-hour average exposure limit of 4 mg/m3 for wheat, oats and barley.
评估加拿大现行的工作场所谷物粉尘接触标准是否恰当。
目前每立方米空气中总谷物粉尘的允许接触限值为10毫克（以毫克/立方米表示），作为8小时时间加权平均接触量，或更低的允许接触限值。
谷物粉尘接触的急性症状，如咳嗽、咳痰、喘息和呼吸困难，类似的慢性症状，以及显示阻塞性或限制性疾病的肺功能测定缺陷。
从《医学索引》及相关文章的参考文献中识别出1924年至1993年12月发表的文章。通过检索MEDLINE获取了1994年（加拿大胸科学会标准委员会批准这些建议时）至1996年6月发表的后续文章，未发现有必要修改这些建议。相关研究是那些将总谷物粉尘水平测量与接触工人急性和慢性呼吸道症状及肺功能变化联系起来的研究。未纳入关于谷物粉尘对饲料厂工人影响的论文，因为谷物中可能添加了其他营养成分，如动物产品。未发表的报告（如提交给加拿大劳工部的报告）被纳入作为信息来源。
高度重视将谷物粉尘对谷物工人肺部造成的生物危害降至最低。
益处、危害和成本：5毫克/立方米的允许接触限值将控制谷物粉尘接触对工人的短期影响。尚无足够证据确定预防长期影响所需的水平。尚未评估实施更低允许接触限值的经济影响。
加拿大劳工部和谷物行业应审查现行的加拿大谷物粉尘接触标准。建议5毫克/立方米的允许接触水平以控制短期影响。应收集更多将加拿大各地工人的接触水平与呼吸道健康影响联系起来的测量数据，以建立接触-反应关系以及谷物粉尘影响可能存在的地区差异。
这些建议尚未经过外部审查。然而，美国政府工业卫生学家会议建议小麦、燕麦和大麦的8小时平均接触限值为4毫克/立方米。
