Exposure measurement, risk assessment and source identification for exposure of traffic assistants to particle-bound PAHs in Tianjin, China

To investigate the levels of exposure to particulate-bound polycyclic aromatic hydrocarbon （PAH） and to estimate the risk these levels pose to traffic assistants （TAs） in Tianjin （a rnegacity in North China）, a measurement campaign （33 all-day exposure samples, 25 occupational-exposure samples and 10 indoor samples） was conducted to characterize the TAs＇ exposure to PAHs, assess the cancer risk and identify the potential sources of exposure. The average total exposure concentration of 14 PAHs was approximately 2871 ＋ 928 ng/rn3 （on-duty）, and 1622 ＋ 457 ng/m3 （all-day）. The indoor PAHs level was 1257 ＋ 107 ng/m3. After 8000 Monte Carlo simulations, the cancer risk resulting from exposure to PAHs was found to be approximately 1.05 x 10-4. A multivariate analysis was applied to identify the potential sources, and the results showed that, in addition to vehicle exhaust, coal combustion and cooking fumes were also another two important contributors to personal PAH exposure. The diagnostic ratios of PAH compounds agree with the source apportionment results derived from principal component analysis.

Assessing the accuracy of patient report of the 5As (ask,assess,advise,assist,and arrange) for smoking cessation counseling

Objective:The 5As framework(ask,advise,assess,assist,arrange)is a recommended strat-egy for smoking cessation counseling in primary care.This study compares patient report with direct observation to assess the degree of recall bias for each of the 5As.Methods:Primary care visits by 107 adult smokers and 16 physicians were audio-recorded.Within 48 hours after the visit,patients completed a survey assessing whether or not smoking was discussed and items specific to each of the 5As.The audio recordings were evaluated to assess the presence of each A.The sensitivity,specificity,positive predictive value,and negative predictive value of patient report versus direct observation were computed.Results:The frequency of the 5As based on evaluation of the audio recording ranged from 13% (arrange)to 98% (ask).The sensitivity and specificity of patient report were 92% and not applicable for ask,90% and 50% for assess,94% and 33% for advise,90% and 50% for assist,and 85% and 67% for arrange follow-up.Positive predictive values ranged from 28% to 98%;negative predictive values ranged from 0% to 97% .Conclusion:Compared with the gold standard of direct observation,patient report of each of the 5As is reasonably sensitive but not specific.Patients overreport the occurrence of each of the 5As.