Formaldehyde Variation after Decoration in Anshun Public Places

Objective To understand the dynamic change of formaldehyde in the indoor air of new decorated public places and its influencing factors.

Methods The concentration of formaldehyde in the indoor air of 50 public places in Anshun City, which had been finished decorating, was monitored from January 2014 to October 2014; temperature, humidity and atmospheric pressure were recorded at the same time; the influence of various factors on the change of formaldehyde concentration was analyzed by using t test, chi-square test and Spearman rank correlation.

Results The change of formaldehyde in 4 months after decoration during winter time was not significant (P > 0.05). The concentration of formaldehyde increased gradually with the rise of temperature in 4 months after decoration in winter time, with a peak value in July (0.202 mg/m³), then it declined gradually; the qualified rate could reach to 72.5% in 10 months. The concentration of formaldehyde decorated in summer time was increasing, it was rising to the top (0.2511 mg/m³) in 2-3 months after decoration, and it was then decreasing; the qualified rate was 70% in 6 months. Through statistical analysis, the influence of temperature and humidity on the concentration of formaldehyde was statistically significant (P < 0.05). There was a significantly positive correlation of temperature with formaldehyde concentration tested by Spearman correlation analysis (χ²=0.867, P=0.007, P < 0.01). There was also a statistical significance on the humidity with formaldehyde concentration tested by chi-square analysis (χ²=5.20, P=5.20, P < 0.05).

Conclusions The concentration of formaldehyde in indoor air of new decorated public places could be influenced by the season. With the diffusion of formaldehyde varied with the change of temperature, humidity and time, the diffusion of formaldehyde was positively correlated with temperature.