The application of benzo(a)pyrene (BaP)-toxic equivalent factor to polycyclic aromatic hydrocarbons (PAH) concentrations can provide a more accurate risk assessment from environmental exposure to PAH. We hypothesized that BaP-equivalent toxicity determined following residential air monitoring among young urban children may vary by season. Residential indoor and outdoor air levels of PAH measured over two-weeks in a cohort of 5–6 year old children (n = 260) in New York City were normalized to the cancer and mutagen potency equivalent factor of BaP (BaP = 1). Data are presented as carcinogenic equivalents (BaP-TEQ) and mutagenic equivalents (BaP-MEQ) for the sum of 8 PAH (∑₈PAH; MW ³ 228) and individual PAH and compared across heating versus nonheating seasons. Results show that heating compared to nonheating season was associated significantly with higher (BaP-TEQ)_∑8PAH and (BaP-MEQ)_∑8PAH both indoors and outdoors (p < 0.001). Outdoor (BaP-TEQ)_∑8PAH and (BaP-MEQ)_∑8PAH were significantly higher than the corresponding indoor measures during the heating season (p < 0.01). These findings suggest that at levels encountered in New York City air, especially during the heating season, residential exposure to PAH may pose an increased risk of cancer and mutation.

This paper reports on validation experiments with the recently developed microAeth®, a pocket-sized device which is able to obtain real-time and personal measurements of black carbon (BC) aerosol. High reproducibility was observed when comparing the results from six new individual units during fixed-site monitoring out of a window (relative standard deviation [RSD] = 8% ± 5%, N = 1442). The results obtained from the microAeth devices agreed with those obtained from a full size rack mounted Aethalometer, based on both the 1-minute data (R = 0.92, slope = 1.01 ± 0.01, N = 1380) and 24-h average data. The 24-h average of real time data obtained from the microAeths was comparable to the BC concentration obtained from 24-h integrated PM2.5 filter deposits, as determined by multi-wavelength optical absorption (R = 0.98, slope = 0.92 ± 0.07, N = 12). Rapid environmental changes in relative humidity (RH) and temperature (T) can result in false positive and negative peaks in the real time BC concentrations, though averages > 1–2-hour are only minimally affected. An inlet with a diffusion drier based on Nafion® tubing was developed in order to use BC data with a high time resolution. The data shows that the diffusion drier greatly reduce the impacts from rapid changes in RH and T when the monitoring system is worn in close proximity to the body (e.g., in the vest pocket).