氮氧化物对文物的危害和变化规律

氮氧化物作为当前主要的空气污染物对文物的危害也越来越受到文物保护工作者的关注。本文介绍氮氧化物、由氮氧化物带来的二次污染物-光化学烟雾中的氧化剂(O_3和PAN)以及氮氧化物在气相或物体表面形成的气态HNO_3和酸雨中的液态HNO_3对各类文物的危害作用。API公司生产的200型NO_x分析仪对上海博物馆在龙吴路的库房和实验大楼周围环境中NO_x与时间、空间、气象等因素的关系进行了连续测定。结果表明:每天清晨6:00-9:00,傍晚15:00-17:30是NO_x的高峰时段;晴天NO_x浓度明显高于阴雨天气;此外,NO_x浓度与空间位置也密切相关。本结果为分析氮氧化物污染来源、选择文物进出或保护处理的适宜时段以及选择合适的检测位置提供参考。

The effects of nitrogen oxides on cultural materials and its atmospheric changes

Nitrogen oxides have become one of the main pollutants along with the growth of the city automobiles in recent years. The effects of nitrogen oxides on cultural materials are also much noticed by conservator. This paper introduced the harmful action of nitrogen oxides including nitrogen dioxide, nitric acid in gaseous state and secondary pollutants (Ozone and PAN) produced by nitrogen oxides etc. Also the pattern the concentration change of nitrogen oxides at the Laboratory surroundings in respect to sampling time, site and weather (sunny or rainy) have been studied by using NOx analyzer. The results showed that the peak concentration of nitrogen oxides is between 6:00 to 9:00 every morning and 15 :00 to 17:30 every evening. The analyses of the daily concentration change of NO2 to NO showed that the first peak of NO2 appeared between 6:00 to 8:00, the first peak of NO was postponed 1 hour later and appeared be- tween 7:00 to 9 : 00. The observations also showed that the NOx pollutants in sunny day is more serious than in rainy day, the concentration change is closely related to the site of sampling. In the paper the problem of where the NOx comes from and why the peak of NO appears lately has been discussed. This study will help the conservator to select the proper time to carry and treat cultural materials, and also to select proper sampling site.