Assessment of polycyclic aromatic hydrocarbons in indoor dust from varying categories of rooms in Changchun city, northeast China

Abstract

Sixteen polycyclic aromatic hydrocarbons (PAHs) were isolated from indoor dust from various categories of rooms in Changchun city, northeast China, including dormitory, office, kitchen, and living rooms. PAH concentrations ranged from 33.9 to 196.4 μg g⁻¹ and 21.8 to 329.6 μg g⁻¹ during summer and winter, respectively, indicating that total PAH concentrations in indoor dust are much higher than those in other media from the urban environment, including soils and sediments. The percentage of five- to six-ring PAHs was high, indicating that PAHs found in indoor dust mainly originate from pyrolysis rather than a petrogenic source. Rooms were divided into three groups using cluster analysis on the basis of 16 PAH compositions, namely smoke-free homes, homes exposed to smoke and offices. Results showed that the source of PAHs in smoke-free residential homes is primarily the burning of fossil fuels. In addition to the burning of fossil fuels, biomass combustion and cooking contributed to PAHs in houses exposed to smoke (including kitchens). Motor vehicles are an additional source of PAHs in offices because of greater interactions with the outdoor environment. The results of health risk assessment showed that the cancer risk levels by dermal contact and ingestion are 10⁴- to 10⁵-fold higher than that by inhalation, suggesting that ingestion and dermal contact of carcinogenic PAHs in dust are more important exposure routes than inhalation of PAHs from air. Although the results showed high potential of PAH concentrations in indoor dust in Changchun for human health risk, caution should be taken to evaluate the risk of PAHs calculated by USEPA standard models with default parameters because habitation styles are different in various categories of rooms.

Appendix

The ILCR was calculated using the followed equations:

$$\begin{aligned} & {\text{ILCRS}}_{\text{Ingestion}} = \frac{{{\text{CS}} \times \left( {{\text{CSF}}_{\text{Ingestion}} \times \sqrt[3]{{\frac{\text{BW}}{70}}}} \right) \times {\text{IR}}_{\text{Ingestion}} \times {\text{EF}} \times {\text{ED}}}}{{{\text{BW}} \times {\text{AT}} \times 10^{6} }} \\ & {\text{ILCRS}}_{\text{Dermal}} = \frac{{{\text{CS}} \times \left( {{\text{CSF}}_{\text{Dermal}} \times \sqrt[3]{{\frac{\text{BW}}{70}}}} \right) \times {\text{SA}} \times {\text{AF}} \times {\text{ABS}} \times {\text{EF}} \times {\text{ED}}}}{{{\text{BW}} \times {\text{AT}} \times 10^{6} }} \\ & {\text{ILCRS}}_{\text{Inhalation}} = \frac{{{\text{CS}} \times \left( {{\text{CSF}}_{\text{Inhalation}} \times \sqrt[3]{{\frac{\text{BW}}{70}}}} \right) \times {\text{IR}}_{\text{Inhalation}} \times {\text{EF}} \times {\text{ED}}}}{{{\text{BW}} \times {\text{AT}} \times {\text{PEF}}}} \\ \end{aligned}$$

where CS is the sum of equal BaP concentrations based on toxic equivalents of BaP by the toxic equivalency factor (Nisbet and LaGoy 1992), CSF is carcinogenic slope factor (mg kg⁻¹ d⁻¹)⁻¹, BW is body weight (kg), AT is the average life span (years), EF is the exposure frequency (d year⁻¹), ED is the exposure duration (years), IR_Inhalation and IR_Ingestion are the inhalation rate (m³ d⁻¹) and soil intake rate (mg d⁻¹), respectively, SA is the dermal surface exposure (cm²), AF is the dermal adherence factor (mg cm⁻² h⁻¹), ABS is the dermal adsorption fraction, and PEF is the particle emission factor (m³ kg⁻¹). CSF_ingestion, CSF_Dermal, and CSF_Inhalation of BaP were addressed as 7.3, 25, and 3.85 (mg kg⁻¹ d⁻¹)⁻¹, respectively, as determined by the cancer-causing ability of BaP (Peng et al. 2011). Other parameters referred to in the model for children (1–6 years old) and adults (7–31 years old) were based on the Risk Assessment Guidance of the USEPA and related publications, shown in Table 3.

Table 3 Parameters used in the incremental lifetime cancer risk assessment (Wang et al. 2011)